Diagnosing the stuck HVAC reversing valve
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- Опубликовано: 5 июн 2013
- I show the symptoms of a stuck reversing valve. This one is stuck partway and is bypassing from high side to low side.
This video is part of the heating and cooling series of training videos made to accompany my websites: www.graycoolingman.com and www.grayfurnaceman.com to pass on what I have learned in many years of service and repair. If you have suggestions or comments they are welcome.
If you are a homeowner looking to repair your own appliance, understand that the voltages can be lethal, the fuels are highly flammable and high pressures are used. Know your limits. 
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I just want to take a moment to thank you for doing what you do. I can't even imagine how many people you have helped. The real world knowledge that you give out for free is priceless. I've been in the field for 25 years but was a little weak with heat pumps. We don't really see many of them in Philly. Well, over the past 10 years they've been getting more popular with all of the condos being built. It's cheaper for them to drop heat pumps in than to run gas lines to each unit & set up the gas meters. I think they might be a little lazy too. It used to mostly be people who ran the gas bill up crazy high. But anyway, thanks man. You've helped me out a lot. This video is awesome. I used to feel overwhelmed when on a heat pump service call & hoped the unit was old enough to justify replacement. I can't say I love changing out a 4 way valve, but it's not as bad when you understand them more. It's actually simple now that I'm confident with them. I cut them out & use some couplings, 90s, & Stay Brite though. I've been using Stay Brite a lot since TX valves have become almost standard. I'm lazy & don't feel like doing a nitrogen purge. Thanks Bud 👍😉
Aren't you the Same guy who said this A.C. man couldn't satisfy a woman?
thanks. I had the same thing and everyone told me it was not the reversing valve and you told me I was right by watching your video. I love it when I can say I told you so lol
The best instructor on line...Period.
The troubleshoot of the RV give a lot of us techs fits, especially when the compressor has failed. As for replacing the RV with the compressor, I blow hot and cold on that one. Many locked rotor failures have no damage to the valve but when you have to tell a customer you have to do most of it all over, you kind of wish you had recommended replacement! Great comments.
GFM
Great video! I have found many a bad RV with the temperature differential method! Simple but effective! Thank you for sharing!
Modern college textbooks teach you to that, whenever a four-way reversing valve is suspected of leaking internally, place your temperature clamps across the low-side line (the indoor coil in the summer or the outdoor coil in the winter) and the permanent suction line between the reversing valve and the compressor.
There shouldn't be more than a 3°F difference between them.
Also, be sure to take the temperature readings at least 5" away from the valve body, in order to keep the valve body's temperature from affecting your readings. To prevent ambient temperature from affecting your temperature readings, insulate your leads for better accuracy.
We love Grayfurnaceman! 🥰🥰🥰
Whoosh! Whoosh! 😆
Enjoyed your vid sir, I'll forward to young contractor friends in the field. Very simple explanation. Beginning my 50th yr in TX. Blessings!
Wow! Thank you so much. Am new to the tech field and this is gonna help me a lot when I do a diagnosed on this type of units.
Thanks for the support.
GFM
I will be doing a vid on the sman. I used them and the testo as a teacher and I actually liked both of them with some reservations. It can be almost impossible to tell the difference between bad valves or a stuck part way valve in some cases. This one was easy because of the position of the slide.
GFM
Thanks. Appreciate your advice. Will kept you posted on the outcome.
Must have solid grasp of the mechanics of reversing valves on this. Luckily GFM has provided a whole playlist on heat pumps. Thanks!
Welcome
GFM
Very helpful and informative!
El jefe at it again - great video demonstration boss.
Always the best videos...Great refreshers and even greater teaching tools...Easy to understand without all the theory that sometimes, is simply, confusing....Is that an oxy moron?...Anyway, I love this mans videos and learn something every time I watch them....Thanks again to the Grayfurnaceman
Thanks for the support.
GFM
Thank you! Just went outside & hit mine with a stick! It's blowing cold air now!
Excellent video. Thank you!!
You are 💯 right same thing happen to me last week after that I realize that valve is bad…
Great video GFM !!! Nice new gauges also !! Take care, Brett
thanks so much for sharing all this Videos 👍😁 you Rock
Welcome
GFM
You're right! That's why I always recommend the customer pay for a new RV, too.
Very clear explanation. Thanks!
Welcome
GFM
A partial charge may not have enough pressure to push the valve across. The electric solenoid starts the action but it's assisted all the way across with refrigerant gas pressure, thus the small cap tubes.
Thanks. I finally had to get my own. I used to use the school's.
GFM
It sounds like the valve actuator is leaking by. Check the power to the solenoid. If it is stable and the valve keeps moving, the valve has failed. I would use a clamp meter to be sure there is no problem with the solenoid. Hope this helps.
GFM
Thanks
GFM
Its a 1980s York Champion. The unit is used as a mule to test and do vids, so for now, it has been repiped as an air conditioner
GFM
Yes, they are great for accuracy, but still keep the analog ones for the dirty jobs!
GFM
Thanks. I'll try that tommorow and let you know thanks.
Very helpful!!
your an awsome old guy, ty for the vid n info
brilliant video. thanks!
+Gene Friedman Welcome
GFM
Worse part about a bad compressor on a heatpump once you replace it you may have something like this happening.
great information
Excellent video...
Nicholas CeeA Thanks
GFM
at 2:08 the pressure for the discharge line is 20.4 while for the suction line it shows 257.3
I guess its possible for the discharge to be blocked in the valve and to leak back into the suction. That would explain the high head. Thanks for the video!
patbhvac1 the part of the valve that is blocked, if anything, are the tiny capillary tubes only used to move the piston, not the bigger suction and discharge fittings...as for the "high" head pressures, we do not know[care] which refrigerant is in this system, which for 410a, normal may be a couple hundred psi.or more.
Where can i get the normal suction and discharge pressure for refrigerants. At least the acceptable ranges. Then i will get more from this video. For example i dont know if your discharge of 258psig is off scale and a clear indication of a restriction. It corresponds to a sat temp of 120F which i assume is much too high. Is there an internal relief valve operating in compressor to protect it at this high value ?
Agree, nice video Thanks!
That RV requires very little diagnosis at all.
The tricky ones are those losing say 10% gas. Infact a multiple of techs may check the machine without picking the fault. Or think the compressor is on its way out.
Temp differential is the best way to pick it generally
i like those old york heat pumps
hey nice video can you do another video on reversing valves
GFM, Good Stuff
thanks !!
hi Gray great video, today I was work on a Trane unit 410A with a reversing & was get the same temp on both condenser & evap line off the valve in cooling , I apply 24v to the sol coil (it was not wire correctly) & it will work for a few them do the same thing again, I'm thing of changing the sol. & the valve, as I think the sol coil is weak & dropping out but why is my temp the same on both lines ? is it not sliding back fully .
It is probably sticking part way. Then it will bypass.
GFM
So reversing valve receives 24 volts from Tstat to control heat and AC . Then it should move from defrost board in and out also? why is int not moving back to heat if defrost has been satisfied . Pressure differential? Why work way with Tstst but not on its own from defrost ? Thank you .
Very nice
Thanks for the support.
GFM
Will The reversing valve still operate/shift even if you are low on charge?
Thanks
You the man
excellent video
+Chad Tinsley Thanks for the support.
GFM
I got a reversing valve anomaly for you. I have a 2011 Trane XR15 3 ton, and a few minutes after it cycles off, the reversing valve starts to hiss and hot gas bypasses to the suction lines. It only does this a few minutes after shut down, and the hot gas bypass seems to stop after the system runs for a minute. Keep in mind the solenoid is cooling active, and it's not de energizing when the thermostat cycles the compressor off.
+Lincoln Hunt If I am correct, Trane does not de energize the valve upon startup. There is a delay. Have not seen the delay after shutdown, but it is probably normal.
GFM
It's just strange that hot gas starts leaking across the valve after the compressor shuts off
Good video...I don't think many who watched got it...if you know what I mean...I did...thanks....
I have a heat pump and the compressor draws low amps. The name plate says 12 amps and my amp meter reads 4 amps. Does this mean that my compressor is weak? I have good head pressure and suction pressure. The compressor is a scroll compressor from 2010. The air handler is a 2 ton with a fixed metering device and there was a 14 inch flex duct return but I added a return plenum and increased the return duct from 14 inch flex to 16 inch flex duct to reduce the noise in the ductwork. there is one return filter grille that is 20x20.
Which line are you clamping?
GFM
I believe its an E1CP024 Model. The model plate is un readable.
GFM
Which model of champion? The only one i've seen is the Champion VI, ( AKA, the tombstone )
New unit time!!!
Im working on a heat pump today and using the standard service connections my pressures are within range for 410 but the compressor keeps overheating and cycling off i suspected the rv as it dose everything youve covered in this video EXCEPT quick equalize infact. I watched it during an off cycle and it attempted to equalize but never got close to equal anything i should check or look for ?
Are you sure your charge is correct?
GFM
grayfurnaceman i didnt have my pt chart so i couldnt confirm my super heat i did take the blanket of the compressor before i left and no call back today so im assuming that helped keep it cooler and not shut off but ill have to check that when i go back out
I have Lennox HP that has blown (shorted 3 R-valve coils (in cooling mode) in the last 2 months, cools great while it's working but the coils shorts out and causes the 24V circuit breaker to blow and then the AC will not work. What could cause the R-valve coil to go bad (short out)? I noticed in your video the R-valve is stuck however the coil is still functioning. Ever had an issue causing the coils to short out? Thank my making such goo videos.
First be sure your coil is seated in its mount. If it is loose, it will overdraw and damage the coil. If it is seated, my thought is the solenoid inside the valve is not moving as far as it should. Means a new valve.
GFM
Hi. You can't imagine how much you help me to be a better technician. If ever you have time to troubleshoot a TXV valve but, in the outside unit, that would help me too. Maybe you already did. If so, please tell me wich video. Thank you for your good work
it means ok?
i'm having the same problem with a 410a system, suction line after the reversing valve is hot, when cooling for cool, but both pressures are equalized at 190 psi, is it safe to say, the reserving valve is no good?
A compressor with bad valves will have equal pressures high and low while running
Dont judge me, I am somewhat of a "rookie" especially heat pumps. What are you jumpering from, to the valve?
Anything w/ 24vac
Sr I like your video too much are very interesting. If don't mind I would like to know in Heat Pump in cooling call why suction pressure line is High and discharge line the pressure is low even when the Thermostat and entirely 24 vol control system is ok.Thank you and Regard Sr
Sounds like a reversing valve problem.
GFM
I know this video is mostly for experts, but it makes me think I'm getting misdiagnosed on my heat pump hvac. My unit cools fine 95% of the time, but every once in awhile I'll try to cool from our day temp setting of 78 down to 72 and it will struggle to cool off one degree...or it will cool off good at first but then I'll wake up at night and it'll be 79 or so. It's not Summer heat related as most days it cools fine still. I'll play with turning the unit off & on for a few hours or two days...and the problem will usually go away for weeks or months.
Pump is good and Puron is full per repairman. He said there was some restriction in the coils & I need new coils. It did seem the system was not cooling properly when he was there. He also quoted for a host of code upgrades like over $100 for the 3 little cap locks on the freon inlets?!? $65 per pound for Puron also seems high.
I know you probably can't know for sure w/o gauging, but it seems if coils were bad the cooling would be bad 100% of the time...not 5%. Plus I stood over the compressor one hot day and it seemed cooler air was coming from the top this unit compared to my other unit.
Any chance you think this is the reversing valve sticking intermittently? Is that cost high? Thank you!
Maybe reversing valve is considered part of the coils system and he just wasn't giving that detailed info?
Probably not the reversing valve. Your tech is probably right about air flow. The coil may be freezing up. Look for frost on the large line.
GFM
Okay, thank you.
Also make sure that you are keeping up with your filters. Clogged filters cause airflow restrictions and will freeze up your coiks as well.
Think along simple lines first. You should never start a diagnosis without a clean evaporator and condenser coil. You would need hvac tools to measure that. An experienced tech would have indicators by just feeling the lines and temperature differences.
Checkout the heat pump playlist. There is another vid about reversing valve operation there. Hope it helps.
GFM
This might not be related to a reverse value issue but here is the problem I am having... I have a programmable stat that is set to 74 when I'm at work and 72 when I'm at home. Sometimes, I'll come home and it's 72 but the AC is still running and when I check the temp coming into the house it's around 61. Other times I come home and it's still at 74 and the temp coming into the house is around 71-73. I also notice the large suction line is barely cool and not sweating even around the 61 degree mark.
The only way I can fix this issue is shut off the ac, switch to heat mode for about 45-60 seconds, shut off the heat, and switch back to cool mode. This seems to work every time as the temp coming into the house cools down to around 57-58 and the large suction line is close to ice cube cold and sweating a good amount.
Now if I just shut off the ac but keep it in cool mode and then turn it back on after the 5 minute system delay, it doesn't solve the problem and 72 degree air continues to run into the house... Would this be a reverse value issue? I thought maybe low on refrigerant but I don't understand how it works just fine when I do the cool,heat, cool switch. If it was low, it shouldn't produce a temp difference of 57 degrees (15-16 degree difference) like nothing is wrong after I do my manual switch... thoughts? After I do this, the system seems to work fine throughout the evening and at night (I continually check the temps coming into the house every time the AC kicks back on the rest of the evening and it hits 58 every time). But something seems to not work right when the program goes to 74 and it can't get cold enough to recover back to 72.
I assume you do have a heat pump. There is no way to know for sure what is going on without actually looking at the unit. It might be a reversing valve not switching over completely but that would be quite unusual.
GFM
you had charging ports close to the compressor to determine the compressor was bad before condemning the RV? That would be tough to diagnose with 2 problems at the same time? was the valves out on the compressor?
A leaking by RV and bad valves in the compressor have the same symptoms.
The only way I know of to determine the difference is to energize the valve and see if it moves. Even this does not always work, as the pressure difference required for the valve to move may not be there in either case.
GFM
Well some reversing valves, dare i say almost all, use pressure to also move, not just the solenoid.
Grey man. I have a question. What do I look for if I have a reversing valve cycling in cool then after cycling on it goes into heat. And vice versa. Again it's calling for cooling but sometimes going into heat then back to cool when it wants to. Thanks
Best guess would be fault in wiring or bad pilot solenoid
If your discharge gas is leaking back into your true suction line your suction will rise and your discharge will drop. Since the refrigerant is going into the suction line and not the condenser you will not build any head pressure or as much as normal. Yes the suction line temp will rise. I have diagnosed over 30 stuck valves and they fail in two ways: The discharge line is leaking into the suction line. Your suction will rise and your head will drop. This looks like weak compressor valves. Typically the valve will stick in the middle and you will get little to no pressure change. This looks like a compressor that is not pumping at all. I am assuming that is 22 and you said you only had a small charge. I would say you have a clogged or stuck metering device or something.
patbhvac1 22, you'ass.u-me.' Such a huge pressure differential between several score and several hundred psi.? a whole pound of refrigerant at such a huge differential isn't gonna equalize THIS quickly over ANY metering device no matter HOW [stuck] open it is, unless you are dealing with my GMC's Pro Air, which two conflicting system charge stickers on the evap. box under the hood indicate that a pound of refrigerant is only 8oz.[lol] which BTW, swallowed 8 14oz. cans of 134a. before it was anywhere near happy to cool.
Man I love your videos and I love HVAC, there is so much to learn. Can I get some advice from you Mr.Grayfurnaceman? I went to school for HVAC, but I'm starting off doing commercial new construction, I don't mind learning it, but I really want to do service. I'm having trouble finding an hvac service apprentice position, everyone is looking for a minimum of 3 years of experience. How do you think I can get my foot in the door? I have been doing commercial new construction for about a year.
Familia Sanchez HVAC have you gotten your foot in the door yet
Steve Izzi Yes! I’m blessed to work for a company that does it all. I work on residential equipment to commercial/industrial equipment. Chillers, boilers, VAVs, FPTs, duct less mini splits, RTUs, Controls, and WSHPs. I’m definitely learning a lot, I love it!
I had a quick question. I think a reversing valve needs at least 50psi to move the internal works from side to side. Wasn't your suction pressure too low to cause the piston to shift? It looks like the small tubes get their pressure strictly from the suction tube in the middle right?
The reversing valve needs a large pressure difference to shift. Even if the suction pressure was 0#, it would shift if the head pressure was 100#. the small tubes get pressure from both head and suction. Hope this helps.
GFM
Thank you it does help
and how is it possible that the liquid can flow from higher pressure from the discharge line to lower pressure in the outdoor coil ?
bbal78 usually it goes through some metering device as a piston or TXV. in this case, the [metering] device becomes the reversing valve, hence the larger than 2-3 deg. temp. differences when a [good] compressor makes a differential.
Thanks for the video. I have 3 ton trane HP XL15i installed 2008 and and electric furnace strips for backup indoor. Have fixed a few things myself, but gave up with multiple problems recently. my new hvac guy friend of a friend who works for carrier after sales determined 3 way valve stuck in AC mode. tried knocking it no luck. I had frozen coils in furnace this summer once due to renos dust in filter. wonder if that might have caused it. HP otherwise clean and working well up til now. he said its a $2500 job to replace the valve and tricky due to gas removal and welding bacause coils right behind it. and he doesnt do that so i lose the HP for heat for now. Is there any fix for this besides replacing the valve? thanks
The problem here is not so much the valve replacement. It is indeed tricky to do but I like replacing them. Great challenge.
The filter problem had no effect on the reversing valve.
Here is the real problem. Your unit is probably R-22. It is very expensive. Could be between $700 and $1,000 for the refrigerant.
That said, I would expect that $1,500 would be the top price.
GFM
@@grayfurnaceman no I have r410. Was fairly new at the time I bought the hp. My guy said I might be able to get a deal on a new r410 hp as 410 to be phased out in 2023. What do you estimate the cost of the valve + labor would be for the 3 way and is the 410 not reusable? He also said repair would probably be done in the shop.
@@grayfurnaceman I guess I was wondering if there's any way to recover a stuck valve understanding it's a sealed system I guess
@@soneeeee4440 Stuck means stuck.
If I was doing the job, I would figure 7 hours labor for diagnosis and repairs. About $650 in parts and recovery equipment.
I would never remove an appliance to work on it in the shop. I would repair in situ.
I make it a practice to never reuse refrigerant, but it can be done.
GFM
20 psig is -5F on suction. Is this normal for outside evaporator in heat mode for R22 ?
The suction pressure depends on outdoor temp. As a ball park number, about 15F below outdoor temp.
GFM
Very similar to bad valves on a recip.
The difference is very hard to determine. The choice on whether to replace the unit is up to the customer. Mine is to give him all the info.
GFM
What about section line to hight over 300 psi Little freezing ? Txv locker ? Can you have any Videos for ?
You are going to have to rephrase. I don't understand.
GFM
Maybe you can help me. Swapped out a dead compressor to run into similar issue. The suction on the valve gets hot when on ac but when I switch to heat mode the return becomes ambient. Not cold or hot. Also, the service port suction line gets hot on heating and cool on cooling. So it's acting like the valve is moving but not all the way. Is there any way the accumulator can get restricted causing these symptoms?
My thoughts are the same as yours. Stuck partway. This is probably what caused the compressor failure.
GFM
@@grayfurnaceman thank you.
i have question,pls help me, this morning im charging the split type unit (r22) and the psi showed low side 55 and the high side show 70, while running the unit, it means (ok) somebody telling thats its ok, but im not satisfied as of now, pls give info, thanks alot,
High side should be much above 70#. Are you sure your gauges are connected correctly? Hi side should be 20 to 30# above ambient. Hope this helps.
GFM
Ok I have a Trane heat pump. The heat stopped working (outside unit only comes on for a few seconds sometimes) The heat strip and fan works. Tried the AC and it works. Could this be the reversing valve bad? Thanks for any help
It could be. There is quite a bit of troubleshoot before you can be sure. When you switch from heat to cool you should hear a swooshing sound from the outdoor unit. That would be the reversing valve changing position.
GFM
Ok thanks....it comes on in heat setting for maybe 30 seconds then shuts off and wont restart until it has sit for a while. It will come on in AC though. I dont know much about HVAC but I may check the solenoid, if it's not that I'll call someone.
I am having an issue hopefully you can help me with? I purchased a brand new Goodman 3.5 ton heat pump/ central unit for my home. Yesterday I finally got it all ready to go and I followed the initial startup procedures as instructed in the manual. The AC side worked fine but when I switched to heating I got nothing, the blower was working but the compressor did not kick in nor was I getting any heat.
Last week I attempted to hook it up but had the wrong type of thermostat wired in, this caused the transformer to short out and I had to replace that as well as I purchased the correct thermostat.
Do you have suggestions as to what might be the issue?
This is almost impossible to diagnose. Except to say you have wired it wrong.
GFM
@@electriccar3253 No the wiring to the thermostat is correct. I was just wondering if when the transformer got shorted out if maybe the capacitor to the reversing valve could have also gotten shorted?
Hey thanks for taking the time to answer and yes I realize it's difficult to diagnose without seeing it. Normally I would just pay someone to come out but I broke my back at work and am currently waiting for a judge to OK my disability. They say it can take up 24 months, hows a person supposed to live?
I hear you on the disability. I have relatives on it and its pretty ugly.
There should not be a capacitor in the reversing valve circuit. When you say you get nothing, does the indoor fan come on? Outdoor unit?
GFM
@@grayfurnaceman - its just the outdoor unit, heat and cool, no indoor fan just the fan (blower) on the outside unit. When I have it on AC I hear the compressor kick on and the big exhaust fan comes on and the blower comes on. When I switch to heat the only thing on is the blower and it's blowing cold air.
Do you have power to Y at the outdoor unit?
GFM
Toast R-v, so pilot we assume is working but sleds not moving ?
The pistons are not moving.
GFM
how come the pressure going into the compressor from the suction line to the compressor is much higher ( 260 psi) than the pressure coming out of the compressor in the discharge line ( 20.4 psi ) ?
Actually, the discharge is is the small line on the bottom of the valve. Remember, of the 3 lines on top of the valve, the middle is suction, of the other 2 lines one will be discharge in heat and one will be discharge in cool. Hope this helps.
GFM
customer called on heat pump not cooling due to roofer making a hole on the refrigerant line. Repaired line ,pressure test, vacuum system added refrigerant and started up unit and added refrigerant by weight to mfg. specs. and Low side pressures stayed at 20 PSI and High pres. is equalize. What is my next step to find out if its the compressor or reversing valve that is damaged.Thanks
It is very hard to tell the difference between a rev valve problem and a compressor with bad valves. You can try removing the refrigerant and adding nitrogen into the high side, then before the unit equalizes, energize the valve. Not easy to accomplish but I would try.
GFM
What's the theory on why the line to the outdoor coil was cooling a bit?
The valve is stuck partially shifted so gasses travel both ways.
GFM
I have freed up stuck RVs before by energizing and denergizing the solenoid or by tapping with the rubber handle of my screwdriver. But that sometimes is not a permanent fix. Have you ever used Supco 88 oil or Renew oil to lube the valve and free it up? I've read really positive reviews on that stuff.
I can't say I have used it. I am skeptical.
GFM
I am skeptical myself!
I had the whoosh but still experienced, hot true suction in heat mode. And true suction freezes in cool mode
Sounds like a valve leaking by.
GFM
why isn't the pressure in the suction line lower than the discharge line , shouldn't the pressure decrease as it go through the evaporator coils ?
bbal78 this is a heat pump and works both directions thanks to act. of a [working] reversing valve. Oh wait, it's stuck.
Last night my ac stopped limbo g cool air. Called a tech to come out today and he ran all his tests and said that I need a new unit or atm east s new condenser. He did nite that the valve did not make the swoosh sound even though the solenoid did move. I’m now more convinced that it’s a bad valve since the compressor does turn on and I’m getting nothing as far as cooling. Now, is there a way to change that valve?
The valve is replaceable. It is an expensive part to replace. Second only to the compressor. Depending on the age of the unit (generally about 15 years), it may not be worth the repair.
GFM
Uh oh I think mine may be bad. No swoosh and it keeps freezing over. I have to manually put it on AC to defrost it then go back to heat.
yup,i double checked,and still showed 70 psi in high side its that rigth?
No. You could have a reversing valve stuck partway. I would check its operation.
GFM
How about when your high pressure switch trips suction pressure at 126 discharge pressure at most 475 runs for 5 to 7 mins and trips I figured it is a bad high pressure switch because the rv was replaced a couple years ago.. it’s 410a and I even saw the pressure switch open at 430psi discharge pressure. Should I suspect the rv or change the switch ? I unfortunately didn’t check the temp difference of the 4 way valve because I figured it is fairly new..
The switch does not appear tone the problem. Your head is too high. Possible part way stuck valve?
GFM
grayfurnaceman thanks for the response
grayfurnaceman I just know high pressure cut out is around 610 and cut in about 500 I’ve seen several carrier units (with piston) having a hot gas discharge of up to 480 490 but never tripping a switch. That’s why I figured this one was different. I thought suction pressure being 125 ish is ok and it would be much higher with high pressure gas flowing straight back to the compressor
@@grayfurnaceman
Just found your channel and video from years ago. Hopefully you remember and I can ask a question. You said in the video you had no way to determine if the compressor was bad without changing it. I saw a video once where the tech pinch off the discharge line before the reversing valve and watched his compressor amps to climb if it the the compressor was salt salt that’s not what I thought to be good. With that testing arrangement I guess it’s sucking back was left in coils. Do you sir agree with this method Thanks
that is a nice gauge and temp probe set who makes that ?
fieldpiece
It looks like he has the Testo set
the other day i ran across a Trane heat pump ..... making odd ticking noise at outdoor unit .... sounded like turn signal and unit did not go into heat mode . Any ideas ?
Jack Wright Little info here. However, could be a rev valve solenoid. Although Trane uses a rev valve energized in cool. I would start disconnecting thermostat wires. Hope this helps.
GFM
Id check power from the defrost control board to the valve. It has to be one of the 2
How can you tell the difference between a bad reversing valve or compressor?
If the compressor will not run due to winding failure, you may not be able to tell the difference.
GFM
Will a stuck reversing valve cause the coil to burn up, if so would this happen in a time period of less than an hour
You will have to explain what you mean by "burn up" the coil.
GFM
@@grayfurnaceman shorted
My heat pump acts funny in ac mode. I have a lennox heat pump 14hpx series. Every few hours it blows warm air even in ac mode. Air is hot enough It will actually raise temp of rooms from 80 to 85. I looked at outdoor unit and when this happens the outside unit fan blows cool air from top.
I then change setting in my thermostat (honeywell focus pro th6000). I make fan to 'on' from 'auto' and set the system to cool till 'cool on' sign comes on.
Any insight will be appreciated.
vikaschopra1973 The system must be energizing the reversing valve. Possible a wiring problem at the thermostat that is energizing the valve when it goes to 2d stage?
GFM
Sometimes a bad reversing valve will have an intermittent problem. You have to make sure to have 24v to the valve. Its possible the compressor is dropping out, but if the condenser discharge is colder than outdoor temp i doubt it. It could be your tstat not energizing the "o" terminal also. You need to call a tech
grayfurnaceman Thanks.
scott shoemaker Thanks
Good video you should get rid of that garbage field piece digital manifold and get testos 550's
Hi, I have a mini split unit, cooling works great, blows great, when I switch to the heat pump, nothing happens inside and outside... can you help me trouble shoot this problem?
It has plenty of refrigerant, no leaks, remote program is fine.
Do you have fan inside and out?
GFM
Yes, both fans work when cooking, but nothing happens when heat is on.
@@Valor4Christ I would be looking for a problem in the low voltage controls. Does the unit use a wireless thermostat?
GFM
grayfurnaceman mean to say “both fans work great while cooling”
grayfurnaceman I will look into the low voltage controls and get back to you.
Most likely the problem is that the Teflon in the valve broke and got the valve stuck in that position and at the same time it is blocking the discharge gas resulting in High discharge pressure and High suction pressure. There is no other way a stuck valve will give you such High pressures. If you also add service ports on the other ends other than the middle suction line, the pressures should be way lower than the pressure reading taken from the discharge line as is now. The fast equalization at shutdown will also take place because the suction is not fully blocked in this particular case. I have taken apart many valve and witnessed this problem.
Probably true. As you have seen from taking apart these valves, they can fail in any position. Thanks for the thoughts.
GFM
Something I'm missing here? Why the high head pressure when much of the discharge is going right into the suction line? In my experience the pressure differences would be small, not super-high head pressure? Symptoms of a worn out compressor is high suction and low head pressures, stuck reversing valves are similar. Please clear this up for me. I'm thinking that the reversing valve is bad, but stuck in AC, but you also have a restriction. Like I said, the pressures shown on your gauges don't add up to a stuck reversing valve, at least this has never happened to me. If have a 15-40psi differential with low current, the real job is to diagnose weather it's the r-valve or compressor. [or both]!
In this case, the piston is stuck in the partially shifted position. The discharge is restricted by the piston. I have had this a couple of times.
GFM
High head pressure in video of 258 psig = 120F would you ever get this high value if reversing valve was not restricted ? Great video but raises many unanswered questions for novices :(
What should suction and discharge pressures be for following cases (acceptable ranges)
1)low charge as in video and reversing valve working fine
2)fully charged and reversing valve working fine