Sir, thank you so much for producing this highly educational video! You have no idea the trouble I have been having these past two weeks trying to fully grasp this simple concept of how a combination gas valve works! I've read the five or six pages in my college text book (Refrigeration & Air Conditioning Technology, Ninth Edition, by Eugene Silberstein) numerous times; but I just couldn't get a clear understanding of it until I watched this video!
I had never touched a floor furnace until recently. A company I do so subcontracting for took over an apartment complex with over 40, 4 unit buildings. I am amazed these things are still in use! I told them I didn’t know anything about them but they assumed since I do HVAC troubleshooting for them I could figure it out. Thanks for this old video!
Had the identical unit and this was a big help in helping me understand the operation!! You the man!!!!! Heater back up and running! Thankls a million!!!
Gotta love these simple units with the steady pilot light lit all the time. For about 2 cents a day in fuel, it keeps draft up the chimney and reduces bugs wasps and the moisture levels.
GFM I think you left out an important part of the valve Solenoid. Thermostat is suppose to switch the heater on. Come across where not enough voltage on the micro thermostat and does not switch the valve on. Pilot is on but therm does not turn on valve.
I see this problem alot, on wall heaters were pilot is on and thermostat is not letting the gas flow. Checked at the thermostat, jumped and gas valve turns on just fine. I believe this is a problem with solenoid but I could be wrong. On a milivolt system
I guess I should rephrase my comment in a form of a question. When th pilot light is lit but the milivolt thermostat does not turn on gas valve. But thermostat is checked and working fine also on top of that wires being jumped at the Thermostat and then the Heater fires up just fine. I don't know what causes this problem. Is there 2 soleniod valves 1for the Thermopile and another for the main valve when switched at the Thermostat that turns on heater? Sorry for the dyslexic comments before this one.
For a long time I have wantes to know how the gas valve operated in a device unattached to the mains electricity supply and no battery. Wikipedia was useless, only explaining how thermocouples worked which I knew already. The thermocouple-operated miniature solenoid came as a surprise as I would have thought that the thermocouple would not be able to operate a solenoid under its own power, but it does. A great explanation and a great series. Thank you.
Really enjoyed your presentation. I work with them all the time. Never took one apart due to possible leaks and you can't rebuild them. So I just throw them out and get replacement.
This is a marvelous set of views of the inside. Thanks so much. Any additional explanation you can provide will be as useful I suspect. I direct people to your video.
Great video, thank you for taking the time to explain these type of gas valves. Although not used in modern furnaces, you still find these in gas operated hot water heaters.
I love your videos ever since I started in this field 7 years ago. I have a huge textbook which pairs nicely with your videos thanks so much for the teachings. im a maint. supervisor at an apartment complex and I recommend your videos to new techs to see the correct way of doing things and principles behind proper operation.
That is awesome! I have worked with these valve's for years but did not want to take one apart because they can be pretty expensive, also time. Thanks!
Thank you, GFM. This is exactly what I needed. I've been working on an older ventless gas fireplace log in my home and couldn't figure out the regulator system. You are a good teacher. -- Bob
The video is great, but it leaves out one important thing: the second solenoid, which was not shown and sits under the electric terminals, routes a small amount of pressurized gas to the bottom of the big diaphragm which effectively operates the main outlet valve (and also regulates the pressure). Gas pressure is used as the operating force for the main valve. This is important on "millivolt" versions of this valve, where a bigger 700 millivolt thermopile provides all the electricity to operate both solenoids. The thermopile would have to be very large to provide enough power to operate the main gas valve all by itself. 190055joe asked how 20 mv can operate the solenoid. The voltage does not "pull in" the solenoid, it just holds the solenoid in its fully-in position. That takes less current/voltage. The solenoid is "pulled in" when the Pilot button is pressed in by the person lighting the pilot.
Actually I did mention that it is pilot operated. I did not explain the operation of that part of the valve because this video is more about how the pilot safety works than how the gas is used to open the valve. Perhaps I should do one on how a pilot valve works. Thanks for the thoughts. GFM
That's the key part of the system that I was wondering about; this video cleared it up as the pull in current for any kind of useful solenoid would be far too high for a thermopile to drive, but since it's the human operator that supplies the force to pull it in, only a small amount of current is needed to maintain it above the drop out voltage of the solenoid coil. Your further description of a gas pressure operated relay completes the system, as the main gas actuation has to be done without human intervention.
It is a gas pressure regulator for the manifold. It is a flame safety control (thermocouple flame safety). It is a manual shut off valve. It is an electrically operated solenoid valve. Hope that helps.
question. I took apart a thermostat (KKTB type model), for a convection oven (gas stove burners and electric oven). has baking (BA), broil (BR) and C(convection?). when i turn the knob for oven the heat element won't go on (I never used the oven after years and this is like the first time I used the oven function - so it can be considered first time). the oven at first came on very high temperature and then after wouldn't come on again. i took it apart to diagnose what the problem could be. the oven part is mostly hardwired, thermostat -> relays -> heat element (bottom and/or top). when i took off the thermostat the parts inside imploded, i put it back together but it seems that the 2 leads (+ and -) going to thermostat to control whether on or off connection is made are always connected state. the springs holding the bracket regardless of whether they are pressed or depressed, a connection (continuity) is always present. this is the only logical way i could find to assemble it back yet it doesn't seem to be correct. there is two brackets, one braket moves kind of up and down to connect to the leads. the other has a spring attached which goes back to the first bracket. then there is the second half of the box which has a round metal piece which is connected to the thermostat sensor, this goes on top of the first bracket. any idea about this type of thermostat?
Great video! When I light my pilot the button doesn’t pop up quickly, rather it takes almost a minute to pop up high enough to move it to ON. Should I be concerned? 1977 Lennox (I have a video on my channel). There is no screw on the button or I would try to put a drop of oil where the screw goes. I don’t see a way to lube it...
Great explanation. This type of valve is on a lot of builder drop-in fireplace units. I was getting mixed up about where to check the thermocouple voltage, now I understand why there is no terminal for it, it's that copper line into the solenoid. Thanks! Unfortunately I still don't know why my fireplace won't light... I got voltages that now check out after cleaning the thermopile -- when it initially failed the voltage was too low and they were fithy. But it still won't light. The troubleshooting things says one other test beside the thermocouple -- to check a the continuity from a safety magnet to ground -- which I can't find. I guess I'll have to replace the whole valve assembly.
Thanks. That helps me understand why the regulator adjustment is so "insensitive", meaning that one screw rotation changes the pressure just a small amount. I guess the screw tensioning (or relaxing) that big weak spring centered on the diaphragm.
A while back I replaced the combination gas valve on our 1964 furnace. Thereafter, I noticed that the burners made a whistling sound (most likely from the gas orifices on the manifold). Eventually, using a water manometer, I dialed the manifold pressure down from 3.5" to 2.75", and the whistling was weaker. Fast forward to today, and using a digital manometer I fiddled with manifold gas pressure again. It would not go above 3.5", and would not go below about 2.66". At around 2.85" the whistling became quieter. Later today, while on our daily walk, my wife comments that the furnace always whistled!
Freaking brilliant explanation! I am wiring my millivolt gas fireplace to a WiFi module for Alexa to turn off/on cause the girlfriend is lazy. Needed to understand how to the valves worked and where I needed to set the transistor-controlled switch to give the 700mV to the main valve.
Good morning, I'm in Brazil and I'm having trouble finding the back cover diaphragm, "6:30 minutes in the video" Could you tell me a preferred store that sells online. thanks
Gas valves are high liability items. Therefore, the manufacturers will not sell any parts for them. Even if the control knob breaks, they will not supply the part. GFM
While pressing PILOT, eventually the solenoid keeps the pilot light valve open. So what then does the ON setting do? I'm trying to follow how the ON valve is first but the pilot light valve opens first ? Thanks
Do you use a sealant when putting the valve back together? I opened an old valve to a wall heater and freed up the stuck diaphragm. But didn't reuse because I didn't know if a sealant was needed?
Any advice on where the adjusting screw is for the pilot light flame on a Tiara II-B ? I replaced the Thermocouple Assy. with a new one from H+Home Tech. Tagged all wires, etc. and replaced as undone. Everything works, including the remote Themostat and control. However the pilot flame is 3" or 4"+ High and wide coming out of the pilot hood. Thx.
There is a pilot adjust slot head on top of the valve. Marked pilot. However, if the pilot is that high, you probably do not have an orifice installed in the pilot tube where it connects to the pilot assembly. GFM
thank you for your video.just wondering how the valve control the diagram shut on/off , the main gas stop supplying when the thermostat reach the set tepmture , how it work ?
The valve is a pilot operated one. A solenoid opens a small valve that allows the gas pressure to fill the diaphragm and open the main valve. Hope this helps. GFM
@grayfurnaceman thank you for your reply .Is that solenoid which hold the pilot? Gas keep coming in when the the pilot stay lit , is that mean the main gas keep pressure the thin diagram , but when we turn off the temp thermostat off , the pilot stay lit but the diagram shut off and the main gas stop. the millivolt drop when burner on (the thermostat on moment),millvolt back around 750 (the thermostat off), is this related?
I just installed a new pilot assembly W010-0790 ( it has both a thermocouple and thermopile ) on an old Napoleon fire place. It has a Robertshaw/Grayson gas valve. My problem is that my gas valve doesn't have a port to thread in the single copper wire from the thermocouple. I think my gas valve has a wire coming out of it that used to go to a separate thermocouple control ( probably held mercury ) that they no longer make. Can you tell me how I could get this hooked up ? Thanks in advance !! Jim ODonnell
the flow control adjustment that you shown in your video, is that for the pilot of the main gas flow control for the burner? I want to get a gas flow control valve that can have a wired thermostat that runs of a power pile. My existing heater is an old Coleman dual sided wall heater and it inconvenient to adjust the heat and a wired thermostat would solve that problem.
There are 2 flow controls on the gas valve. One is a set screw for the pilot adjustment and the other is a manifold pressure adjustment. Neither will work with a thermostat. However what you may have is a hydraulic valve that has a temp sensing bulb and an adjustment to change the gas flow to the burner. If it is a hydraulic valve there is no way to control except by adjusting the knob. GFM
@@grayfurnaceman I was planning on purchasing an entire Williams Monterey Plus gas valve, thermostat, stack senser, and pilot/power pile and removing my old gas valve to replace it with the Williams equipment. Thank you for your response!
I have a garage furnace with a White Rodgers combo valve. The TC is making over 25mV. I think I have a bad TC connection to the solenoid, open solenoid coil or stuck solenoid. Is it possible to test the pilot solenoid coil resistance with the TC disconnected? Black meter lead to valve body and red to the solenoid connection? Thanks if you can help
Hey really appreciate the video! I was just wondering if you could explain what it means when the pilot nob does not spring back when released (in the pilot setting). For example, the pilot lights as normally during start up procedure, however once I let go of pressure on the knob, it does not spring back to the closed position. If I slightly tug on the nob it then shuts off.. In the owners manual for the unit, it specifically mentions if this happens then to shut it off immediately and call for a qualified service/maintenance provider. I have shut the unit off, just wondering if this is typical of a specific problem? I am sort of assuming it will need a whole new combination gas valve?
I can’t figure this out anywhere. I’m using a patio heater with the Shaw pilot knob. I have been looking for an explanation as to how the knob assembly works. It’s supposed to turn easily from off to pilot, then you must press down to light the pilot and then it will continue to the full on position. You can manually hold the pilot knob down and turn it to on to ignite the burner of the thermocouple doesn’t work (it shuts off once you stop pushing the knob). I was fiddling with the knob and it seems as though it got reversed mechanically? Now I can’t turn it to the off position without pushing down on the knob, but it will turn right from off to on without pressing down. (The opposite of the proper mechanism behavior) I was trying to learn how that mechanism works to fix it but that wasn’t discussed here (or anywhere) have you heard of this happening?
Have old Warm Morning heater that I love. It has fan that is not used. It has the same on/off/pilot valve as pictured. Tan, push down for pilot turn to on when It has started. Easy to start. It periodically starts roaring when running, nothing consistent. From quiet to softish steady roar. I jump up, turn it to low and it often stops the roar and I quickly turn it back up and it works fine with roar gone. One time I had to turn off the gas at the pipe and right back on when just turning it down did not stop it. Since there is no motor running - just the gas coming through the lines... is it air coming through with the propane? Sound old tank is half full. Old regulator? Smell no leaks. Went through a spat of this happening around 4 am on cold mornings, but that seems to have quit. Out of the blue, it just did it again this (cold outside) evening. Help!!! No one seems to know what I am talking about. Thank for any help.
Do the solenoid ever go bad... if so, can it be replaced .... I’m thinking... yes, no????????? ...I’m working on a Honeywell V810A1210 gas valve and the price brand new is $365.00 .... haven’t tested yet( the thermocouple for DCmv) ... just want to cover my bases, as you know it’s a old furnace.....you showed in your video, the seloniod... trying to look for this part.... can you help me please....
Thanks so much for saving me the trouble of curious disassembly! I run an electronics lab and was curious as to how a ~30mV signal could hold a solenoid open without extra amplification circuitry. It's also nice to see the thermocouple solenoid come out so easily; a couple of additional pointers may have been helpful such as: can you simply take out the thermocouple solenoid while the gas is switched off? and can you generally purchase the thermocouple solenoids by themselves or must you purchase an entire combination valve?
Hi, i hear a clicking sound from gas valve when thermostat calls for heat. But the pilot is off. Does this clicking sound means that the gas valve is being energized and gas is going to burner even though the pilot is off? Thanks
The pilot safety valve is in series with the main gas valve. If either valve is closed, gas will not flow, either to the pilot or the main gas in virtually all gas valves. GFM
I have an old furnace. I tried to use this a few days ago. I turned the heater on via thermostat, and no warm air came out of the vent (but the fan was turning). I checked the pilot light and it was off. I re-lightened it (meaning gas was there). I turned the heater on again, with the same result. I checked the gas valve, TR and TH, 27V AC was there. Any suggestions?
I ‘ve seen a system that was around before thermocouples and ran the pilot tube from a small valve on the gas valve to the appliance. Can you find one do a video on?
Hi Mr. Gray: I have a ventless gas stove and I would like to convert the thermocouple to an external digital type. If it's possible, can you explain how that can be done?
The pilot solenoid is not replaceable on the gas valve. If the pilot safety was opening, it would not relight. I would be looking at the low voltage controls such as the thermostat or limit switch. GFM
does this valve works the same as those dual intermittent pilot gas valves that use with intermittent spark ignition module? i was working on a york RTU with two gas valves. the terminals on the gas valve were TR, TH/TR, TH. the TH/TR was connected to PV of ignition module. the TH was connected to MV of the module. the TR was connected to ground. if i were to measure from TH/TR to TR i should get 24vac to open the pilot gas correct? and if measured from TH to TR i should get 24vac to open main valve for burner correct? so does this mean this gas valve has two coils? one for pilot gas and one for main burner? thank you.
The safety valve operation is understood. When calling for heat, the large gas turn on is a little murky to understand. Electric from the same thermocouple?
If the valve is a millivolt controlled valve, it uses either the thermocouple or a thermopile to power main gas. The valve could also be powered from an outside power source. Either 24 volts or 120 volts. Hope this helps. GFM
grayfurnaceman Thank you. My 1962 model gas valve does not have any external power supply for the main valve operation. BUT we do have (2) two pilot lights. yes, two. one thru the gas valve for the primary valve and a SECOND pilot outside of the valve DIRECTLY to the pilot. Thank you once more, Only power comes from the therm..... whichever one we have.
Williams Enclosed Hearth Heater model number 5001911. Pilot stays lit and main burner not firing up. Attempted to purge the air out of the line via the pilot tube but found minimal gas pressure in line. I heard no gas flow when opening the shut off valve to purge. Replaced integral twin stage regulator out by propane tank. Pressure is audible now and enough to purge line. Pilot light stays lit with blue flame Millivolt reading 30mV on thermocouple. Pilot knob is set to "ON" position. Problem: Turning the control valve to maximum, gas valve not opening. After shutting off pilot light, 180+ seconds later the "click" can be heard of solenoid disengaging from magnet in gas valve. Question: How can the solenoid open and there be no gas coming out to the burners? I'll cut and paste this same question on some of your other videos in hopes of getting it noticed.
Your system is, I believe, a thermopile system. The thermocouple holds open the pilot solenoid. The thermopile operates the main solenoid. I would guess the thermopile is weak or there are loose connections. Hope this helps. GFM
Thanks for the video. What do you recommended if the knob will not turn while pressing down? Could it be grease caught in the valve (deep fat fryer). Thanks!
Actually, grease should make it easier to turn. These valves are designed so that the knob will break off if it gets too stiff to turn. Replace the valve. GFM
Very thorough videos. I installed a Williams Montery (wall furnace) that I bought used. Didn't work until I replaced the thermopile. (I disassembled everything except the burners and control to clean the furnace.) Then the pilot ignited just fine but the burners did not light. The troubleshooting guide said to replace the gas valve (Robertshaw 710-502) which I did. The furnace now works very well. I took apart the old valve to see what failed. Everything looked good. When I tested the various terminals for continuity, I had good results. There is a wire from (what I think is) the burner control solenoid over to the terminal block. I get continuity there too. Should there be continuity when the valve is not connected to a source of electricity? From your articles, I get the feeling that this is a short, leading to what some call a "stuck valve." Is that what it could be? I couldn't pull out the soleniod, but based on your article for "chain control," I suspect that it the problem. Please comment.
Emphasis on "hold". Except for certain limited applications, they will only hold a pilot valve open. Check out HVAC part suppliers on the internet looking for general replacement combination gas valve. GFM
Hi i have a pitco frialator fryer and it works fine but right before the temp starts to drop and wants to turn back on i smell gas than it turns on and the smell goes away and i thought that the combi valve is bad and replaced it but still have the same problem thanks for your videos.
Help! I have standing flame furnace with a 36c53-418 gas valve. The pilot keeps going out after 1-2 hours. I've changed thermocouple and high temp sensor. There is no flame roll-out. Earlier today I reignited the pilot, set gas valve to on, thermostat clicked and burners roared and fan forced air... the thermostat reached temp and burners shut down but noticed a flame sputter at base of burner tubes (where they meet perpendicular to gas tube going into furnace chamber) leading into furnace - pilot remained lit. I raised the temp on thermostat and furnace went on normally and again sputtering at base of tubes leading into furnace when thermostat reached temp - pilot still lit ( nice fanned flame hitting thermocouple). On the 3rd sequence the thermostat sent signal for heat and boom like a backfire the pilot went out and I can hear the gas hissing. Shut off furnace and gas line. Can this be a faulty gas valve 36c53-418. Cold n almost blowup in NJ
Thank for you this video, it was very informative. So if my flames on my propane deep fryer are not blue but yellow, which way should I turn the regulator? I was told they should be blue so they’re burning at a high enough temperature.
Turn the regulator Clockwise. There’s a reason why you’re not getting enough gas. A manometer should determine the w.c pressure. Should be 10-11 for LP and 3.5 for Natural gas.
thanks for video. I believe I have a combo gas valve. I foolishly took it apart and some of the oil(?) leaked from the thermocouple area. do you know what is the liquid in there? it looks like a light oil but I cant be sure.
A blank screen indicates no power to the thermostat or, in the case of a battery operated thermostat, dead batteries. The only case that I can think of where the gas valve can cause a blank screen is if there was a dead short in the valve. First, check power to the appliance. GFM
GFM,I am replacing my Honeywell vs820a1047 gas valve.The current (bad) valve is installed vertically.Is a vertical mount ok,or does the gas valve need to be horizontal?Feels like a stupid question,but,I cannot find a definitive answer.Thank you,Robert.
Wondering if you can recommend a replacement gas valve for a fireplace? Parts are discontinuedNat Gas 23,000 btuThermopile only need a Pilot Push Button … thanks
Honeywell VS821A1269 - it has Thermopile and Mercury switch - switch does not work and no replacement a tech told me to go Thermopile only but suggested a valve with no push button start ...
Great video. Thank you. Do you know a good source to find compatible replacement valves for a 30 year old fireplace? I’m having a hard find finding one for my fireplace.
@@grayfurnaceman Thank you very much for responding. I have not been able to find the owners manual on-line to look at the parts list and determine what valve it is. What I do know is that it is a Superior Fireplace insert, model GI-3821P (liquid propane). Any help is much appreciated.
@@grayfurnaceman I hired a fireplace specialist to clean the fireplace and he tested everything and told me the valve was leaking and cannot use the fireplace until the valve is replaced.
@@carlop445 If you can send some pics of the valve and let me know whether it is 24 volt or millivolt controlled, I may be able to help. Send to Grayfurnaceman@gmail.com GFM
This is exactly the system I have and even thought the thermal coupler was changed heater won’t stay ton for long time . I’ll hear a click and pilot is out. I can relight pilot light but when I turn to gas it goes out what to do ?
The reasons for that type of failure are numerous. Is the pilot covering the thermocouple at least 3/8"? Is there any draft hood spillage? Is the thermocouple tightened reasonably? GFM
Some furnaces I see, the combination valve still allow some gas to flow to the burners even when the thermostat is not calling for heat. (Smell gas). Is this normal or should the combination valve be replaced?
I have an old gravity furnace (1981) hydro flame model brc 10a in my RV. I wore out the thread of the solenoid receiving the thermocouple. Wonder if replacement solenoids are available out there. Thanks.
If the unit has a separate components as its gas control, it is probably best to replace the assembly with a combination control valve. Such as the Robertshaw 710-502. This valve is a millivolt controlled one. I don't know if yours is millivolt or 24 volt. Hope this helps. GFM
Hey... can you assist me..my Imperial fryer main burner wont shut off ...even if I adjust the thermostat......I've change thermostat, high limit switch, theromnpile .... and the pilot light is good ...
Great video! My furnace just stopped working. I saw its pilot was not lit. I am able to lit the pilot and start the furnace but, after heating the room when when burners go off pilot also goes off! I checked the thermocouple is generates about 23 millivolt. Any suggestion how to fix it?
If the pilot light goes out with the burner, you could have a dirty burner. Sometimes, when the burner goes out, it will pull the flame off the pilot. Also, there could be a problem with the primary air adjustment. GFM
Problem has gone worse. When I turn the thermostat to high temperature, pilot goes very very dim . Nothing else changes - burners don't lit, blower don't start. When I turn the thermostat back to low temperature setting, pilot flame become normal.
I have a Superior direct vent gas fireplace, model # dt-600cmn. The pilot stays lit but go off whenever I turn the knob at the gas valve from Pilot to On. Thermopile reading is 374 to 380 millivolt, while the thermopile is reading about 80 millivolt. I unplugged both thermopile and thermocouple wires from the gas value but the pilot light still go off immediately when I turn the gas value to the On position. I would greatly appreciate if you can suggestion what else I can test to isolate where the problem is.
Open circuit voltage should 500 mv. Closed circuit should be 125 mv. You are a bit low. Is the flame blue and covering the thermopile? Are the connection tight? GFM
Hi Want ask a question why after light up the burners and reach the satisfied the temperature. The burner fire off and the pilot flame off all together. Thankyou
The answer to that question depends on whether you have an intermittent pilot or a standing pilot control system. If it is intermittent, it is normal for the pilot to go off when the thermostat is satisfied. If it is a standing pilot, and the pilot goes out, the control system shuts down and will not reignite without a manual relight of the pilot. Let me know which you have and I may be able to help. GFM
I put a voltmeter across the end of the thermocouple-the end that screws into solenoid. I put one lead on end of plug looking part that screws into solenoid assembly and other lead just on outside of copper that comes from thermocouple and got 0.1 ohms (nearly no resistance). I am curious how the thermocouple voltage is sensed/received by the solenoid. I also measured the resistance inside the solenoid (between end and side of solenoid cylinder and again got nearly no resistance. So my question is: where precisely is the voltage difference from the solenoid taken at end of thermocouple and where precisely is the voltage from the thermocouple received? It appears to me like magic because both the thermocouple opposite end seems shorted and also the solenoid housing seems shorted. I guess now I should heat the thermocouple and measure to find out where the voltage difference is on the the opposite thermocouple end is being generated.
The thermocouple is a junction of dissimilar metals that, when heated, produces a small current. Just use your voltmeter in DC volts across where you originally placed the ohmmeter. GFM
@@grayfurnaceman Thanks, yes I need to do that while heating the thermocouple end to see what the voltage is. The thing keeps going out on Fridays at restaurant...think when door is opened alot it increases likelihood of blowing out pilot light.
@@russ8001 If this is in a restaurant, you probably do not have a thermocouple problem. The exhaust and makeup air are probably not balanced. A vacuum in the kitchen will pull the flame out of the appliance. GFM
I have a head scratcher. I smell gas when my boiler lights up and it takes longer (30sec) to ignite than before. Weil Mclain boiler, steam over gas system. Lit pilot. Has a robertshaw 7000erhc-s7c vale. Says it has slow opening feature for soft ignition. Any ideas before I replace the valve? Looks like the one in your vid. No complaints otherwise and everything looks visually good. Thanks for good vids.
good video, thank you, just have a question, hope you still are around to respond, is it possible for debris to hold that big circular thin rubber vavle open, i constantly have a flow of gas from the out port as long as the pilot is on, or do you think that it has ruptured? also it didn't leak for the first 2 months of operation, and now makes a squeek sound when it closes
Your unit is probably millivolt. Be sure the terminals are tight and clean. The pilot should cover the thermopile and be all blue. Millivolt reading with the valve turned on should be 125 MV. GFM
@@grayfurnaceman thanks...i cleaned up the heat sensor and it fired up for about 2 seconds and then it shut down. So I turned the gas off and Ill get a professional out to fix it.
What is the most common reason that a gas valve pilot will light but won't pass gas to keep burners lit? Have run into this a few times - normally we just replace the valve.
This depends on the age, make and model of the unit. Some very old units have the gas valves directly controlled by the thermostat. Newer ones are controlled by the control board which is then controlled by the thermostat. GFM
Dear GFM, I have an old wall mounted Peerless gas furnace in an old garage on my property. I tried lighting it the other day after years of none service. The heater started to work after the pilot was lit. Once the main burner kicked in all was fine then the gas valve started burning from a leak around the control knob. We instantly turned of the supply. Are these combination valves repairable if it is just a stem seal that has gone bad. In this video the control knob is beige. It's the same valve as mine. Thanks.
10 years later and it is still a useful video.
This is one of the best videos explaining how a gas valve operates, period.
Thanks for the support.
GFM
Thank you for teaching . 🎉 there are not lot of people explaining this very well like you
Well done. It is always a pleasure listening to a dissertation from a tradesman who knows what he’s talking about.
Sir, thank you so much for producing this highly educational video! You have no idea the trouble I have been having these past two weeks trying to fully grasp this simple concept of how a combination gas valve works!
I've read the five or six pages in my college text book (Refrigeration & Air Conditioning Technology, Ninth Edition, by Eugene Silberstein) numerous times; but I just couldn't get a clear understanding of it until I watched this video!
Glad it helped.
GFM
I had never touched a floor furnace until recently. A company I do so subcontracting for took over an apartment complex with over 40, 4 unit buildings. I am amazed these things are still in use! I told them I didn’t know anything about them but they assumed since I do HVAC troubleshooting for them I could figure it out. Thanks for this old video!
Had the identical unit and this was a big help in helping me understand the operation!! You the man!!!!! Heater back up and running! Thankls a million!!!
Thanks for the great explanation of the combination valve. Nothing beats seeing things taken apart and explained.
Gotta love these simple units with the steady pilot light lit all the time. For about 2 cents a day in fuel, it keeps draft up the chimney and reduces bugs wasps and the moisture levels.
.60 a month.
You are the best instructor in HVAC . I wish you have an happy thanks giving to you and your family .God bless you .
+quang nguyen Thank you and the same to you.
GFM
GFM I think you left out an important part of the valve Solenoid. Thermostat is suppose to switch the heater on. Come across where not enough voltage on the micro thermostat and does not switch the valve on. Pilot is on but therm does not turn on valve.
What the heck are you saying?
GFM
I see this problem alot, on wall heaters were pilot is on and thermostat is not letting the gas flow. Checked at the thermostat, jumped and gas valve turns on just fine. I believe this is a problem with solenoid but I could be wrong. On a milivolt system
I guess I should rephrase my comment in a form of a question. When th pilot light is lit but the milivolt thermostat does not turn on gas valve. But thermostat is checked and working fine also on top of that wires being jumped at the Thermostat and then the Heater fires up just fine. I don't know what causes this problem. Is there 2 soleniod valves 1for the Thermopile and another for the main valve when switched at the Thermostat that turns on heater? Sorry for the dyslexic comments before this one.
For a long time I have wantes to know how the gas valve operated in a device unattached to the mains electricity supply and no battery. Wikipedia was useless, only explaining how thermocouples worked which I knew already. The thermocouple-operated miniature solenoid came as a surprise as I would have thought that the thermocouple would not be able to operate a solenoid under its own power, but it does. A great explanation and a great series. Thank you.
crazeygrazey
Really enjoyed your presentation. I work with them all the time. Never took one apart due to possible leaks and you can't rebuild them. So I just throw them out and get replacement.
This is a marvelous set of views of the inside. Thanks so much. Any additional explanation you can provide will be as useful I suspect. I direct people to your video.
The way you explained makes me easy to understand, thank you very much for the video.
Solid information. Thanks for posting your videos. I'm going to R&R the gas valve in my fireplace today. Watched your video on that, too.
+Mike Florey Welcome
GFM
Great video, thank you for taking the time to explain these type of gas valves. Although not used in modern furnaces, you still find these in gas operated hot water heaters.
Welcome
GFM
I love your videos ever since I started in this field 7 years ago. I have a huge textbook which pairs nicely with your videos thanks so much for the teachings. im a maint. supervisor at an apartment complex and I recommend your videos to new techs to see the correct way of doing things and principles behind proper operation.
Carlton Joe Thanks for the support.
GFM
Thank you for helping me understand how a gas valve work.
I finally figured out whats wrong with my gas fireplace!!! Thanks to you. Couldn't find info on it anywhere
Glad you got it going.
GFM
That is awesome! I have worked with these valve's for years but did not want to take one apart because they can be pretty expensive, also time. Thanks!
Fantastic video, thank you very much. I always love knowing how things like this work.
The best explanation I have seen . Thank you.
We are learning about these in school and this helped me out allot thanks.
Welcome, good luck in the business.
GFM
Thank you, GFM. This is exactly what I needed. I've been working on an older ventless gas fireplace log in my home and couldn't figure out the regulator system. You are a good teacher. -- Bob
The video is great, but it leaves out one important thing: the second solenoid, which was not shown and sits under the electric terminals, routes a small amount of pressurized gas to the bottom of the big diaphragm which effectively operates the main outlet valve (and also regulates the pressure). Gas pressure is used as the operating force for the main valve. This is important on "millivolt" versions of this valve, where a bigger 700 millivolt thermopile provides all the electricity to operate both solenoids. The thermopile would have to be very large to provide enough power to operate the main gas valve all by itself.
190055joe asked how 20 mv can operate the solenoid. The voltage does not "pull in" the solenoid, it just holds the solenoid in its fully-in position. That takes less current/voltage. The solenoid is "pulled in" when the Pilot button is pressed in by the person lighting the pilot.
Actually I did mention that it is pilot operated. I did not explain the operation of that part of the valve because this video is more about how the pilot safety works than how the gas is used to open the valve. Perhaps I should do one on how a pilot valve works. Thanks for the thoughts.
GFM
That's the key part of the system that I was wondering about; this video cleared it up as the pull in current for any kind of useful solenoid would be far too high for a thermopile to drive, but since it's the human operator that supplies the force to pull it in, only a small amount of current is needed to maintain it above the drop out voltage of the solenoid coil. Your further description of a gas pressure operated relay completes the system, as the main gas actuation has to be done without human intervention.
Thank you Sir, I think you are absolutely wonderful, thank you for all your educational videos.
Welcome
GFM
It is a gas pressure regulator for the manifold. It is a flame safety control (thermocouple flame safety). It is a manual shut off valve. It is an electrically operated solenoid valve. Hope that helps.
question. I took apart a thermostat (KKTB type model), for a convection oven (gas stove burners and electric oven). has baking (BA), broil (BR) and C(convection?).
when i turn the knob for oven the heat element won't go on (I never used the oven after years and this is like the first time I used the oven function - so it can be considered first time). the oven at first came on very high temperature and then after wouldn't come on again.
i took it apart to diagnose what the problem could be.
the oven part is mostly hardwired, thermostat -> relays -> heat element (bottom and/or top).
when i took off the thermostat the parts inside imploded,
i put it back together but it seems that the 2 leads (+ and -) going to thermostat to control whether on or off connection is made are always connected state. the springs holding the bracket regardless of whether they are pressed or depressed, a connection (continuity) is always present. this is the only logical way i could find to assemble it back yet it doesn't seem to be correct.
there is two brackets, one braket moves kind of up and down to connect to the leads. the other has a spring attached which goes back to the first bracket.
then there is the second half of the box which has a round metal piece which is connected to the thermostat sensor, this goes on top of the first bracket.
any idea about this type of thermostat?
Great video, I always wondered what was inside of these.
thanks, video took out that intimidation factor and i replace the valve myself
Great video! When I light my pilot the button doesn’t pop up quickly, rather it takes almost a minute to pop up high enough to move it to ON. Should I be concerned? 1977 Lennox (I have a video on my channel). There is no screw on the button or I would try to put a drop of oil where the screw goes. I don’t see a way to lube it...
Great explanation. This type of valve is on a lot of builder drop-in fireplace units. I was getting mixed up about where to check the thermocouple voltage, now I understand why there is no terminal for it, it's that copper line into the solenoid. Thanks! Unfortunately I still don't know why my fireplace won't light... I got voltages that now check out after cleaning the thermopile -- when it initially failed the voltage was too low and they were fithy. But it still won't light. The troubleshooting things says one other test beside the thermocouple -- to check a the continuity from a safety magnet to ground -- which I can't find. I guess I'll have to replace the whole valve assembly.
Thanks. That helps me understand why the regulator adjustment is so "insensitive", meaning that one screw rotation changes the pressure just a small amount. I guess the screw tensioning (or relaxing) that big weak spring centered on the diaphragm.
A while back I replaced the combination gas valve on our 1964 furnace. Thereafter, I noticed that the burners made a whistling sound (most likely from the gas orifices on the manifold). Eventually, using a water manometer, I dialed the manifold pressure down from 3.5" to 2.75", and the whistling was weaker. Fast forward to today, and using a digital manometer I fiddled with manifold gas pressure again. It would not go above 3.5", and would not go below about 2.66". At around 2.85" the whistling became quieter. Later today, while on our daily walk, my wife comments that the furnace always whistled!
Gotta listen to the expert.
GFM
Freaking brilliant explanation! I am wiring my millivolt gas fireplace to a WiFi module for Alexa to turn off/on cause the girlfriend is lazy. Needed to understand how to the valves worked and where I needed to set the transistor-controlled switch to give the 700mV to the main valve.
Good morning, I'm in Brazil and I'm having trouble finding the back cover diaphragm, "6:30 minutes in the video" Could you tell me a preferred store that sells online.
thanks
Gas valves are high liability items. Therefore, the manufacturers will not sell any parts for them. Even if the control knob breaks, they will not supply the part.
GFM
@@grayfurnaceman thanks for the provision
Thank you for your showing, really helpful.
great video what would keep the pilot knob stuck at the pilot position. I won't turn on or off
The valves sometimes jam inside the valve. Means a new valve.
GFM
While pressing PILOT, eventually the solenoid keeps the pilot light valve open. So what then does the ON setting do? I'm trying to follow how the ON valve is first but the pilot light valve opens first ? Thanks
Do you use a sealant when putting the valve back together? I opened an old valve to a wall heater and freed up the stuck diaphragm. But didn't reuse because I didn't know if a sealant was needed?
Under no circumstances do I repair and reuse the combination gas valve. Its just not safe. This video is for explanation only.
GFM
very good video that explain this valve ! Thank you so much !
Any advice on where the adjusting screw is for the pilot light flame on a Tiara II-B ? I replaced the Thermocouple Assy. with a new one from H+Home Tech. Tagged all wires, etc. and replaced as undone. Everything works, including the remote Themostat and control. However the pilot flame is 3" or 4"+ High and wide coming out of the pilot hood. Thx.
There is a pilot adjust slot head on top of the valve. Marked pilot.
However, if the pilot is that high, you probably do not have an orifice installed in the pilot tube where it connects to the pilot assembly.
GFM
Awesome video, love the detail, I just learned all there is to know about it in 8 minutes, how great is that??? Thank you...
thank you for your video.just wondering how the valve control the diagram shut on/off , the main gas stop supplying when the thermostat reach the set tepmture , how it work ?
The valve is a pilot operated one. A solenoid opens a small valve that allows the gas pressure to fill the diaphragm and open the main valve. Hope this helps.
GFM
@grayfurnaceman thank you for your reply .Is that solenoid which hold the pilot? Gas keep coming in when the the pilot stay lit , is that mean the main gas keep pressure the thin diagram , but when we turn off the temp thermostat off , the pilot stay lit but the diagram shut off and the main gas stop. the millivolt drop when burner on (the thermostat on moment),millvolt back around 750 (the thermostat off), is this related?
I just installed a new pilot assembly W010-0790 ( it has both a thermocouple and thermopile ) on an old Napoleon fire place. It has a Robertshaw/Grayson gas valve. My problem is that my gas valve doesn't have a port to thread in the single copper wire from the thermocouple. I think my gas valve has a wire coming out of it that used to go to a separate thermocouple control ( probably held mercury ) that they no longer make. Can you tell me how I could get this hooked up ? Thanks in advance !! Jim ODonnell
the flow control adjustment that you shown in your video, is that for the pilot of the main gas flow control for the burner? I want to get a gas flow control valve that can have a wired thermostat that runs of a power pile. My existing heater is an old Coleman dual sided wall heater and it inconvenient to adjust the heat and a wired thermostat would solve that problem.
There are 2 flow controls on the gas valve. One is a set screw for the pilot adjustment and the other is a manifold pressure adjustment. Neither will work with a thermostat. However what you may have is a hydraulic valve that has a temp sensing bulb and an adjustment to change the gas flow to the burner. If it is a hydraulic valve there is no way to control except by adjusting the knob.
GFM
@@grayfurnaceman I was planning on purchasing an entire Williams Monterey Plus gas valve, thermostat, stack senser, and pilot/power pile and removing my old gas valve to replace it with the Williams equipment. Thank you for your response!
I have a garage furnace with a White Rodgers combo valve. The TC is making over 25mV. I think I have a bad TC connection to the solenoid, open solenoid coil or stuck solenoid. Is it possible to test the pilot solenoid coil resistance with the TC disconnected? Black meter lead to valve body and red to the solenoid connection? Thanks if you can help
What happens when the button is released? Pilot goes out? Stays lit?
GFM
Hey really appreciate the video! I was just wondering if you could explain what it means when the pilot nob does not spring back when released (in the pilot setting). For example, the pilot lights as normally during start up procedure, however once I let go of pressure on the knob, it does not spring back to the closed position. If I slightly tug on the nob it then shuts off.. In the owners manual for the unit, it specifically mentions if this happens then to shut it off immediately and call for a qualified service/maintenance provider. I have shut the unit off, just wondering if this is typical of a specific problem? I am sort of assuming it will need a whole new combination gas valve?
If the knob does not pop back up when released, it is now a safety hazard. It must be replaced.
GFM
I can’t figure this out anywhere. I’m using a patio heater with the Shaw pilot knob. I have been looking for an explanation as to how the knob assembly works. It’s supposed to turn easily from off to pilot, then you must press down to light the pilot and then it will continue to the full on position. You can manually hold the pilot knob down and turn it to on to ignite the burner of the thermocouple doesn’t work (it shuts off once you stop pushing the knob).
I was fiddling with the knob and it seems as though it got reversed mechanically? Now I can’t turn it to the off position without pushing down on the knob, but it will turn right from off to on without pressing down. (The opposite of the proper mechanism behavior) I was trying to learn how that mechanism works to fix it but that wasn’t discussed here (or anywhere) have you heard of this happening?
I probably cannot be of help here. The only thing I know is that if the knob gets stiff, you are pretty much stuck with replacing the valve.
GFM
Have old Warm Morning heater that I love. It has fan that is not used. It has the same on/off/pilot valve as pictured. Tan, push down for pilot turn to on when It has started. Easy to start. It periodically starts roaring when running, nothing consistent. From quiet to softish steady roar. I jump up, turn it to low and it often stops the roar and I quickly turn it back up and it works fine with roar gone. One time I had to turn off the gas at the pipe and right back on when just turning it down did not stop it. Since there is no motor running - just the gas coming through the lines... is it air coming through with the propane? Sound old tank is half full. Old regulator? Smell no leaks. Went through a spat of this happening around 4 am on cold mornings, but that seems to have quit. Out of the blue, it just did it again this (cold outside) evening. Help!!! No one seems to know what I am talking about. Thank for any help.
Great video can you do a video explaining the terminals on the gas valve and what they do exactly? Thanks
NICE DRILL OLD MAN
Do the solenoid ever go bad... if so, can it be replaced .... I’m thinking... yes, no????????? ...I’m working on a Honeywell V810A1210 gas valve and the price brand new is $365.00 .... haven’t tested yet( the thermocouple for DCmv) ... just want to cover my bases, as you know it’s a old furnace.....you showed in your video, the seloniod... trying to look for this part.... can you help me please....
Thanks so much for saving me the trouble of curious disassembly! I run an electronics lab and was curious as to how a ~30mV signal could hold a solenoid open without extra amplification circuitry. It's also nice to see the thermocouple solenoid come out so easily; a couple of additional pointers may have been helpful such as: can you simply take out the thermocouple solenoid while the gas is switched off? and can you generally purchase the thermocouple solenoids by themselves or must you purchase an entire combination valve?
Hi, i hear a clicking sound from gas valve when thermostat calls for heat. But the pilot is off. Does this clicking sound means that the gas valve is being energized and gas is going to burner even though the pilot is off? Thanks
The pilot safety valve is in series with the main gas valve. If either valve is closed, gas will not flow, either to the pilot or the main gas in virtually all gas valves.
GFM
I have an old furnace. I tried to use this a few days ago. I turned the heater on via thermostat, and no warm air came out of the vent (but the fan was turning). I checked the pilot light and it was off. I re-lightened it (meaning gas was there). I turned the heater on again, with the same result. I checked the gas valve, TR and TH, 27V AC was there. Any suggestions?
Using your info, the gas valve has failed.
GFM
I ‘ve seen a system that was around before thermocouples and ran the pilot tube from a small valve on the gas valve to the appliance. Can you find one do a video on?
There were some like that made before wwII. Can you say kaboom?
GFM
@@grayfurnaceman How does that valve turn off?
I can imagine the issues because bad pilot would lead to the furnace not igniting and potentially filling the area with gas.
@@andystitt3887 Could certainly do that.
GFM
Hi Mr. Gray: I have a ventless gas stove and I would like to convert the thermocouple to an external digital type. If it's possible, can you explain how that can be done?
I have this gas valve but with an ignition system pfg8. Keeps cutting on an off can it be the valve ? Should I change the pilot solenoid first ?
The pilot solenoid is not replaceable on the gas valve.
If the pilot safety was opening, it would not relight.
I would be looking at the low voltage controls such as the thermostat or limit switch.
GFM
does this valve works the same as those dual intermittent pilot gas valves that use with intermittent spark ignition module? i was working on a york RTU with two gas valves. the terminals on the gas valve were TR, TH/TR, TH. the TH/TR was connected to PV of ignition module. the TH was connected to MV of the module. the TR was connected to ground. if i were to measure from TH/TR to TR i should get 24vac to open the pilot gas correct? and if measured from TH to TR i should get 24vac to open main valve for burner correct? so does this mean this gas valve has two coils? one for pilot gas and one for main burner? thank you.
The safety valve operation is understood. When calling for heat, the large gas
turn on is a little murky to understand. Electric from the same thermocouple?
If the valve is a millivolt controlled valve, it uses either the thermocouple or a thermopile to power main gas.
The valve could also be powered from an outside power source. Either 24 volts or 120 volts. Hope this helps.
GFM
grayfurnaceman Thank you. My 1962 model gas valve does not have any external power supply for the main valve operation. BUT we do have (2) two pilot lights. yes, two. one thru the gas valve for the primary valve and a SECOND
pilot outside of the valve DIRECTLY to the pilot. Thank you once more,
Only power comes from the therm..... whichever one we have.
@@tedlahm5740 It appears to have a millivolt control.
GFM
Hi, is there a way to get a replacement solenoid for a gas valve?
No. The valve parts are not replaceable.
GFM
Thank you Gary. 🙏🏾❤️
been wondering about this valve... thanks!
Williams Enclosed Hearth Heater model number 5001911. Pilot stays lit and main burner not firing up. Attempted to purge the air out of the line via the pilot tube but found minimal gas pressure in line. I heard no gas flow when opening the shut off valve to purge.
Replaced integral twin stage regulator out by propane tank. Pressure is audible now and enough to purge line.
Pilot light stays lit with blue flame
Millivolt reading 30mV on thermocouple.
Pilot knob is set to "ON" position.
Problem: Turning the control valve to maximum, gas valve not opening.
After shutting off pilot light, 180+ seconds later the "click" can be heard of solenoid disengaging from magnet in gas valve.
Question: How can the solenoid open and there be no gas coming out to the burners? I'll cut and paste this same question on some of your other videos in hopes of getting it noticed.
Your system is, I believe, a thermopile system. The thermocouple holds open the pilot solenoid. The thermopile operates the main solenoid. I would guess the thermopile is weak or there are loose connections. Hope this helps.
GFM
Thanks for the video. What do you recommended if the knob will not turn while pressing down? Could it be grease caught in the valve (deep fat fryer). Thanks!
Actually, grease should make it easier to turn. These valves are designed so that the knob will break off if it gets too stiff to turn. Replace the valve.
GFM
Ok thank you!!
Thanks for your efforts. Very helpful ! Keep it up !
Welcome
GFM
Very thorough videos. I installed a Williams Montery (wall furnace) that I bought used. Didn't work until I replaced the thermopile. (I disassembled everything except the burners and control to clean the furnace.) Then the pilot ignited just fine but the burners did not light. The troubleshooting guide said to replace the gas valve (Robertshaw 710-502) which I did. The furnace now works very well. I took apart the old valve to see what failed. Everything looked good. When I tested the various terminals for continuity, I had good results. There is a wire from (what I think is) the burner control solenoid over to the terminal block. I get continuity there too. Should there be continuity when the valve is not connected to a source of electricity? From your articles, I get the feeling that this is a short, leading to what some call a "stuck valve." Is that what it could be? I couldn't pull out the soleniod, but based on your article for "chain control," I suspect that it the problem. Please comment.
Emphasis on "hold". Except for certain limited applications, they will only hold a pilot valve open. Check out HVAC part suppliers on the internet looking for general replacement combination gas valve.
GFM
There should be a cap with a screwdriver slot with the words "pilot adjust" near. The adjustment is under the cap.
GFM
Hi i have a pitco frialator fryer and it works fine but right before the temp starts to drop and wants to turn back on i smell gas than it turns on and the smell goes away and i thought that the combi valve is bad and replaced it but still have the same problem thanks for your videos.
Help! I have standing flame furnace with a 36c53-418 gas valve. The pilot keeps going out after 1-2 hours. I've changed thermocouple and high temp sensor. There is no flame roll-out. Earlier today I reignited the pilot, set gas valve to on, thermostat clicked and burners roared and fan forced air... the thermostat reached temp and burners shut down but noticed a flame sputter at base of burner tubes (where they meet perpendicular to gas tube going into furnace chamber) leading into furnace - pilot remained lit. I raised the temp on thermostat and furnace went on normally and again sputtering at base of tubes leading into furnace when thermostat reached temp - pilot still lit ( nice fanned flame hitting thermocouple). On the 3rd sequence the thermostat sent signal for heat and boom like a backfire the pilot went out and I can hear the gas hissing. Shut off furnace and gas line. Can this be a faulty gas valve 36c53-418. Cold n almost blowup in NJ
The first thing I would do is clean and readjust burners.
GFM
My gas fireplace has a Couple and a thermopile. Why does it have both of these components?
The thermocouple is for flame safety.
The thermopile is to power the gas valve.
GFM
Thank for you this video, it was very informative. So if my flames on my propane deep fryer are not blue but yellow, which way should I turn the regulator? I was told they should be blue so they’re burning at a high enough temperature.
Turn the regulator Clockwise. There’s a reason why you’re not getting enough gas. A manometer should determine the w.c pressure. Should be 10-11 for LP and 3.5 for Natural gas.
So if the pilot won’t stay lit after replacing thermocouple?
If there is no ECO in the thermocouple circuit, and the thermocouple is clean and tight, you have a gas valve problem.
GFM
thanks for video. I believe I have a combo gas valve. I foolishly took it apart and some of the oil(?) leaked from the thermocouple area. do you know what is the liquid in there? it looks like a light oil but I cant be sure.
Its probably a hydraulic valve. I don't know what type of oil it is.
GFM
If this valve is bad will it prevent a digital thermostat from operating ? I have a blank screen
A blank screen indicates no power to the thermostat or, in the case of a battery operated thermostat, dead batteries.
The only case that I can think of where the gas valve can cause a blank screen is if there was a dead short in the valve.
First, check power to the appliance.
GFM
@@grayfurnaceman will do !!!
GFM,I am replacing my Honeywell vs820a1047 gas valve.The current (bad) valve is installed vertically.Is a vertical mount ok,or does the gas valve need to be horizontal?Feels like a stupid question,but,I cannot find a definitive answer.Thank you,Robert.
The answer is located in the install instructions of the valve.
GFM
Wondering if you can recommend a replacement gas valve for a fireplace? Parts are discontinuedNat Gas 23,000 btuThermopile only need a Pilot Push Button … thanks
Give me the make and model of the valve.
GFM
Honeywell VS821A1269 - it has Thermopile and Mercury switch - switch does not work and no replacement a tech told me to go Thermopile only but suggested a valve with no push button start ...
@@warnerdundas3919 I would also recommend a thermopile system. The pushbutton start may be impracticable.
GFM
Fireplace is sealed in
Can you provide a manufacture name - I can’t seem to get any help form vendors
the pilot flame on our 1964 furnace used about $6 worth of gas in one year. Hardly an energy hog.
Would an auto shutoff device turn off gas if there a pressure surge?
Gas valves are designed for a maximum of 1/2" WC of pressure. So it may or may not shut it down.
GFM
@@grayfurnaceman So blowouts are possible in which case the gas keeps flowing out.
@@andystitt3887 Potentially, the diaphragms in the gas valve may be damaged which would allow gas to pass thru the valve.
GFM
Great video. Thank you. Do you know a good source to find compatible replacement valves for a 30 year old fireplace? I’m having a hard find finding one for my fireplace.
If you can give me a make and model of the valve, I may be able to help.
GFM
@@grayfurnaceman
Thank you very much for responding. I have not been able to find the owners manual on-line to look at the parts list and determine what valve it is. What I do know is that it is a Superior Fireplace insert, model GI-3821P (liquid propane). Any help is much appreciated.
@@carlop445 First, how do you know the valve has failed?
GFM
@@grayfurnaceman
I hired a fireplace specialist to clean the fireplace and he tested everything and told me the valve was leaking and cannot use the fireplace until the valve is replaced.
@@carlop445 If you can send some pics of the valve and let me know whether it is 24 volt or millivolt controlled, I may be able to help. Send to Grayfurnaceman@gmail.com
GFM
This is exactly the system I have and even thought the thermal coupler was changed heater won’t stay ton for long time . I’ll hear a click and pilot is out. I can relight pilot light but when I turn to gas it goes out what to do ?
The reasons for that type of failure are numerous. Is the pilot covering the thermocouple at least 3/8"? Is there any draft hood spillage? Is the thermocouple tightened reasonably?
GFM
My do some, whit red flame why?
Some furnaces I see, the combination valve still allow some gas to flow to the burners even when the thermostat is not calling for heat. (Smell gas). Is this normal or should the combination valve be replaced?
papato3 Any flow through main gas when there is no call for heat, replace the valve.
GFM
I have an old gravity furnace (1981) hydro flame model brc 10a in my RV. I wore out the thread of the solenoid receiving the thermocouple. Wonder if replacement solenoids are available out there. Thanks.
If the unit has a separate components as its gas control, it is probably best to replace the assembly with a combination control valve. Such as the Robertshaw 710-502. This valve is a millivolt controlled one. I don't know if yours is millivolt or 24 volt. Hope this helps.
GFM
Its a 30 millivolt thermocouple
Hey... can you assist me..my Imperial fryer main burner wont shut off ...even if I adjust the thermostat......I've change thermostat, high limit switch, theromnpile .... and the pilot light is good ...
Sounds like you are down to the gas valve.
GFM
@@grayfurnaceman thank you sir... i figured it might be that ....what if the gas valve millivolt magnet is bad and need to be replaced ?
@@allandabiedeen Unless the magnet is a separate component, it is not replaceable. The entire valve must be replaced.
GFM
Great video! My furnace just stopped working. I saw its pilot was not lit. I am able to lit the pilot and start the furnace but, after heating the room when when burners go off pilot also goes off! I checked the thermocouple is generates about 23 millivolt. Any suggestion how to fix it?
If the pilot light goes out with the burner, you could have a dirty burner. Sometimes, when the burner goes out, it will pull the flame off the pilot. Also, there could be a problem with the primary air adjustment.
GFM
Problem has gone worse. When I turn the thermostat to high temperature, pilot goes very very dim . Nothing else changes - burners don't lit, blower don't start. When I turn the thermostat back to low temperature setting, pilot flame become normal.
@@eshala505 Is this propane?
GFM
It is gas
@@eshala505 Do any other gas appliances on the same gas line operate ok?
GFM
I have a Superior direct vent gas fireplace, model # dt-600cmn. The pilot stays lit but go off whenever I turn the knob at the gas valve from Pilot to On. Thermopile reading is 374 to 380 millivolt, while the thermopile is reading about 80 millivolt. I unplugged both thermopile and thermocouple wires from the gas value but the pilot light still go off immediately when I turn the gas value to the On position. I would greatly appreciate if you can suggestion what else I can test to isolate where the problem is.
Open circuit voltage should 500 mv. Closed circuit should be 125 mv. You are a bit low. Is the flame blue and covering the thermopile? Are the connection tight?
GFM
Hi
Want ask a question why after light up the burners and reach the satisfied the temperature.
The burner fire off and the pilot flame off all together.
Thankyou
The answer to that question depends on whether you have an intermittent pilot or a standing pilot control system.
If it is intermittent, it is normal for the pilot to go off when the thermostat is satisfied.
If it is a standing pilot, and the pilot goes out, the control system shuts down and will not reignite without a manual relight of the pilot.
Let me know which you have and I may be able to help.
GFM
It is the standing pilot
Ta
Pilot flame
?
Sometimes cleaning of the burners will help.
If it is a conversion burner, a slow closing gas valve may stop the problem.
GFM@@irenechan9389
I put a voltmeter across the end of the thermocouple-the end that screws into solenoid. I put one lead on end of plug looking part that screws into solenoid assembly and other lead just on outside of copper that comes from thermocouple and got 0.1 ohms (nearly no resistance). I am curious how the thermocouple voltage is sensed/received by the solenoid. I also measured the resistance inside the solenoid (between end and side of solenoid cylinder and again got nearly no resistance. So my question is: where precisely is the voltage difference from the solenoid taken at end of thermocouple and where precisely is the voltage from the thermocouple received? It appears to me like magic because both the thermocouple opposite end seems shorted and also the solenoid housing seems shorted. I guess now I should heat the thermocouple and measure to find out where the voltage difference is on the the opposite thermocouple end is being generated.
The thermocouple is a junction of dissimilar metals that, when heated, produces a small current.
Just use your voltmeter in DC volts across where you originally placed the ohmmeter.
GFM
@@grayfurnaceman Thanks, yes I need to do that while heating the thermocouple end to see what the voltage is. The thing keeps going out on Fridays at restaurant...think when door is opened alot it increases likelihood of blowing out pilot light.
@@russ8001 If this is in a restaurant, you probably do not have a thermocouple problem. The exhaust and makeup air are probably not balanced. A vacuum in the kitchen will pull the flame out of the appliance.
GFM
I have a head scratcher. I smell gas when my boiler lights up and it takes longer (30sec) to ignite than before. Weil Mclain boiler, steam over gas system. Lit pilot. Has a robertshaw 7000erhc-s7c vale. Says it has slow opening feature for soft ignition. Any ideas before I replace the valve? Looks like the one in your vid. No complaints otherwise and everything looks visually good. Thanks for good vids.
First, I would try cleaning the burners.
GFM
if the 24 volt transformer shorts ... can it kill the gas valve?
I guess it could but I have never seen it.
GFM
good video, thank you, just have a question, hope you still are around to respond, is it possible for debris to hold that big circular thin rubber vavle open, i constantly have a flow of gas from the out port as long as the pilot is on, or do you think that it has ruptured? also it didn't leak for the first 2 months of operation, and now makes a squeek sound when it closes
Replace the valve. I have never repaired one and do not recommend any repair of these valves.
GFM
Looks like I have the same unit on my gas fireplace..will ignite the pilot but will not move to the on position....is there a good replacement?
Your unit is probably millivolt. Be sure the terminals are tight and clean. The pilot should cover the thermopile and be all blue. Millivolt reading with the valve turned on should be 125 MV.
GFM
@@grayfurnaceman thanks...i cleaned up the heat sensor and it fired up for about 2 seconds and then it shut down. So I turned the gas off and Ill get a professional out to fix it.
Great video, do you know if I can buy the thermopile magnetic valve anywhere. Thanks
This is a great explanation. Many thanks
Welcome
GFM
What is the most common reason that a gas valve pilot will light but won't pass gas to keep burners lit? Have run into this a few times - normally we just replace the valve.
If it is a standing pilot, and 24 volt power is available to the valve, either the valve has failed or there is a supply problem.
GFM
Hello, what are the 4 functions of that combination gas valve, if you would be so kind????
What could be the problem? The furnace seems to work like normal. I just so happened to blow the pilot out and the gas continued to flow.
If the gas flows longer than 3 minutes after the pilot has been extinguished, the gas valve must be replaced. It is a safety hazard.
GFM
does the thermostat also control the gas valve? is there another valve somewhere in there control the gas to the burner?
This depends on the age, make and model of the unit. Some very old units have the gas valves directly controlled by the thermostat. Newer ones are controlled by the control board which is then controlled by the thermostat.
GFM
Dear GFM, I have an old wall mounted Peerless gas furnace in an old garage on my property. I tried lighting it the other day after years of none service. The heater started to work after the pilot was lit. Once the main burner kicked in all was fine then the gas valve started burning from a leak around the control knob. We instantly turned of the supply. Are these combination valves repairable if it is just a stem seal that has gone bad. In this video the control knob is beige. It's the same valve as mine. Thanks.
The valve must be replaced as a whole. No parts are available.
GFM
grayfurnaceman Thank you for the swift reply. Great channel by the way.
Thanks for the support.
GFM
Hi I am asking a newbie question. The two wires goes to the the terminals is 24 VAC right? Thanks
Yes.
GFM