Our Inverter Mini Split Resources: Mini Split Book on Our Website- www.acservicetech.com/mini-split-book Mini Split Paperback on Amazon- amzn.to/3ytHJSs Mini Split Paperback on TruTech Tools- www.trutechtools.com/BooksGuides?aff=8 Mini Split E-Book on Google- play.google.com/store/books/details?id=HN-iEAAAQBAJ Mini Split E-Book on Apple- books.apple.com/us/book/id6445178399 Our Single Speed and Two Speed Air Conditioning Resources: My Paperback and E-Book: www.acservicetech.com/the-book My Paperback: www.amazon.com/shop/acservicetech Read the book reviews on Amazon! Check out our new Articles at www.acservicetech.com/articles Support the Channel by purchasing tools through Tru Tech Tools! Use this link www.trutechtools.com/?Aff=8 Save 8% at checkout using code "acservicetech" My Service and Procedure Book- www.acservicetech.com/the-book Tool List- www.amazon.com/shop/acservicetech Support- www.patreon.com/acservicetech For those that are looking for the tools used in the videos: (Linked Below) UEI DL479 Multimeter with temp sensor amzn.to/2jtsUbJ Magnet Jumpers- amzn.to/2PyKPQZ Alligator Jumpers- amzn.to/2PxqJXn Fieldpiece ST4 Dual Temp Meter amzn.to/2wc1ME3 Fieldpiece Bead K Type Temp Sensor amzn.to/2DBwKfs Fieldpiece Wet Bulb Temp Sensor amzn.to/2RRI7Tw Fieldpiece TC24 Temp Clamp amzn.to/2qHLyjZ Yellow Jacket Refrigerant Gauge Set amzn.to/2aenwTq Refrigerant hoses with valves amzn.to/2aBumVI Yellow Jacket Gauge set & hoses amzn.to/2vLVkV9 Yellow Jacket 4 Port Manifold w Hoses amzn.to/2BkuGIq FieldpieceSMAN360 Digital Manifold Set amzn.to/2BdoaD4 FieldpieceSMAN460 Digital Manifold Set amzn.to/2nB4Fe6 Compact Ball Valve for Refrigerant Hose amzn.to/2KUisW8 QuickDisconnect 90 for refrigerant hose amzn.to/2MMtVcg JB 6 CFM Vacuum Pump amzn.to/2nqbvo8 Appion Blue 3/8" to 1/4" Vacuum Hose amzn.to/2uYlVyc Appion Red 3/8" to 1/4" Vacuum Hose amzn.to/2uYg6Ro Appion Valve Core Removal Tool amzn.to/2uYr8WL Yellow Jacket 1/4" by 1/4" hose amzn.to/2umtcod CPS Vacuum Micron Gauge amzn.to/2v1nM3O Supco Vacuum Micron Gauge amzn.to/2v1JRiA RectorSeal Bubble Gas Leak Detector amzn.to/2ckWACn UEI DL389 Multimeter amzn.to/2xAdaJf Air Acetylene Torch setup amzn.to/2aQalsb 15% Silver Brazing Rods amzn.to/2gVLyLc Nitrogen Regulator amzn.to/2bXdR5f Nitrogen Flow Meter amzn.to/2brvoBg Other tool links can be found in the video description section. Shop through Amazon! Your Purchases through Amazon provide a means for channels such as mine to earn advertising fees from all purchases after clicking through. Prices are the same as normal- www.amazon.com/shop/acservicetech
so before i do anything, i should shut off power to house right? so i dont get electrocuted? then open the panel display? I have a honeywell CT500 that goes blank every so often and now not generating cold air...i have a brand new AC unit too. it has no batteries, so that cant be the problem. i also reset the circuit breakers and the display panel of thermostat still goes blank and then re-appears. it does this every few minutes or so. is it a problem with the wire connection of thermostat? is it loose?
I recommend calling a tech but they would shut the power to the hvac system off and take the tstat face plate off and tighten the connections on both ends, in the thermostat and in the furnace or air handler. After that they will check for 24v to the thermostat and if they have it then it is a bad thermostat. It could also be one of the pins not aligning on the back of the thermostat.
Thank you for saving me a costly service visit! Your suggestion of tapping the R and G wires helped me confirm a bad thermostat! Thank you for taking the time to produce easy to follow instructional videos with detailed explanations that don’t require hvac training to understand!
Hi---It looks like you understood what he said about the red and green wire. Did he say the thermostat is bad if the fan DOES come on when touching the red and green wires together or if the fan DOESN'T come on? Thanks for your help. Jesus bless.
My man!!!!!!!! After I changed almost everything in the furnace, not works until I did the test G and R and the thermostat was bad . Now my furnace work like 7/11 store non stop. Thank you so much bro
For anyone who's control panel is working and whose unit is fine but doesn't seem to be sending data: If continuity from the screws to the copper is good, look at the AC unit's circuit board and check the fuse(should be purple or amber). I accidentally blew it somehow when moving the thermostat. Easy fix!
Great to Hear and in this trade, we all will always be learning! Keep it up because over time you will move up the ladder right past those that stop searching for answers and learning new things! Thanks
Thank you I’ve literally watched atleast 2 videos every day and I’ve become a better tech because of you thanks a lot I have to get better at gas furnaces and diagnosing electrical issues
Great video and a good explanation of why the industry moved away from the old mercury switch. Those switches would bounce those compressors on and off until the mercury settled. A five minute delay is a bit long but better safe than sorry.
I been seeing your videos for 2 years before I became a tech , and even now I always see them and learn dude . Ur a great teacher , I can only image how your helpers or family members who are intrested in the trade turns out to be man . Thanks and please always keep uploading more videos .
Another way I have done it. I used the pins on the back of the thermostat battery operated type. Call for blower the pins should ohm out. Same thing for calling for heat. Make sure you are connecting to the correct pins because they are not marked you have to reference how the pins plug into the back plate.
Thank you for the wonderful videos. I have an issue I am troubleshooting, if you can chime in. IFB sends 24v to the condenser every three minutes regardless of the indoor temperature reaching to the set temperature on the thermostat. Air handler and blower fan keeps running blowing warm air through vents after outdoor unit is off and until compressor engages again in three minutes. So the condenser fan and compressor are on for three minutes and off for three minutes. Subcooling on the unit checks out fine using liquid line pressure and temperature so not suspecting high or low pressure in the system. Contactor leads receive 24v every three minutes. I have checked the main and fan control board for damage or loose wires. This short cycling is not as bad but I think I have an issue I can figure out. Thank you in advance!
I had a call where the AH was running but the condenser was not. I had no voltage between C and Y at the control board outside or the AH. Pulled out the Tstat and jumped between R and Y and the system came on. Tstat was bad.
Awesome. Girl Power. You helped me figure it out. I GOT HEAT. I so refused to call service man. I knew if air conditioner worked and I tested just like you showed to boot the fan, then I knew it wasn't the furnace. I have where red wire could go either to RC or RH, it was at RC so I hooked red to RH and I got heat. Thank you
Even though you now have heat, that's not really the proper way to do that. You shouldn't have to constantly switch your live wire over every time you want to switch between heating and cooling. If you only have one red wire coming in from furnace control board, it should be hooked into the RH terminal, while a separate jumper wire should be connected between RH and RC.
So clearly explained and helpful. Thank you so much. Lets me know if I should call our utility that installed the energy saving thermostat or if it's time to call an AC tech without wasting his time or mine.
Do you know if having the capacitor changed on an exterior HVAC unit would cause the thermostat to behave differently on both heat and cool? For example, I had the heat set at 69, was cold this morning, so bumped it up to 70. Waited a few seconds, nothing. Bumped it up to 71, it started immediately. Room temp when finished was 70 though, measured by a refrigerator thermometer I had balanced on top of the thermostat. Another example, AC was set to 73, and I dropped it to 72. At 72 (the desired temp), unit kept running. End temp was 72, according to that refrigerator thermometer, but it normally would have shut off once the thermostat read 72, not kept running. There have been maybe 15 second delays for the unit to kick on after changing temps, though I swear I could hear the one in the basement kick on immediately when I was playing with it last night, just not the exterior unit. I've been playing around quite a bit with it, so I forget what's what. I just know the unit would kick on immediately with any temp adjustment, up or down, even if I switched directly from heat to cool or cool to heat right away. It's a forced air electric heat pump, if that matters. I almost wish he hadn't changed the capacitor because I liked the way the thermostat used to behave. I even went out and bought a new thermostat, the same one, $100, that I plan to install myself today, just so that they don't charge me $400 to install theirs when another place comes by tomorrow. Actually, that was the price they quoted to install mine. I don't want them telling me something else is wrong, if there isn't. Plus, I need to see how a brand new thermostat behaves so that I know what to tell them.
I know this is an old video but, I only have a red and white wire going to my thermostat. When I turn the heat on for my thermostat the boiler runs for a while and then shuts off. A couple minutes later it kicks back on and so on. It just keeps running like that no matter what the heat it set on. You can have it set to 60 and the temp will keep climbing...We've replaced the thermostat with the same one like three times and still get the same outcome. I just turned the boiler off and touched the red and white and turned the boiler on and it kicked on. I've had a couple people look at it and nobody has an answer.
Hi. The screen on my thermostat is blank. I replaced batteries, nothing. A couple days was back on. Now blank again…but, if I press the temperature up, it comes on (not the screen, the furnace). Also, if I turn fan on it comes on. Any ideas 💡. Thanks so much.
Thank you for this video, the logical path you have laid out, though not exactly the issue I had, it helped me draft my own plan and it helped me diagnose my issue. I was getting 24V at the thermostat, and at the circuit board at the air-handler in my basement. I can hear the thermostat click when I switch to AC or Heat. Heat came-on (this was summer and 80 F Day so I had to set the thermostat to 82 or something to get it to work, but it worked, the AC however did not. Knowing that I got 24V (my meter showed about 27v), so I knew volts should be going out to condenser outside. But the condenser did not start. I saw no 24V at the contactor. I pushed the contactor and it started, condenser and I held it there for a few minutes and family inside confirmed getting cold air, so I knew no issues with the condenser/ compressor. So basically the issue was between the wire that came out of air-handler to the condenser outside. I started following the 24V wires from the contactor to the wall, and I found the issue. I should have looked for this as soon as I found a mice nest in the condenser, they had chewed one of the 24V wires and thus contactor did not get the juice it needed to kick-in the condenser. Once I patched the wire, everything was working again. I have seen folks ask where to buy some of the electrical parts (Contactor, Transformer, Capacitor, etc.) I found these on-line, but you have to wait for a few days, alternatively if you need one quickly I was able to buy at Grainger that is not too far from me, and a GPS (General Plumbing Supply) they had some of the parts I needed as well. This is just an FYI.
Question about colors of wire and the location on what letter the colored wire is placed. On my thermostat there is not a yellow wire. Only red, green & blue. Red on R Green on G Blue on Y No wire on W When I check with the wire red & green my fan does turn on. If I understand correctly that means it’s my thermostat front that needs replacing. I may have screwed up the compressor by checking (R) and blue (Y). Is it the letter location that matters? Or, did I wreck something by checking Y & R because Y has the blue wire? My air conditioner is controlled thru the thermostat. The Rc is the AC? If so how come there is not a colored wired attached? Ii know that G is my fan and it turns on. As shared I tried R & Y and nothing happened; I don’t know where to check the AC unit either only having 3 wires versus 4.
Thank you very much for your video. My system was keeping running when both inside and setting temperatures are matched, what is caused the problem inside the air-handler, need help?
My furnace wouldn't turn on, and I realized that the problem started after I had changed the thermostat batteries. Checked the thermostat wiring and thought that the excess dielectric grease that was on the male and female terminals was causing a problem, then realized that because of the awkward location where the thermostat was mounted, that the display portion of the thermostat hadn't fully seated all the pins. If you didn't look at it closely, you couldn't see it wasn't seated.all the way It allowed me to run the fan, but not run anything in auto, therefore no call from the thermostat. Motto: Make sure the face plate is fully and evenly seated.
Hello Craig. I was working in the field and ran across a thermostat that the voltage on the R and Y was 16 volts, it also showed 16 volts in the air handler and 16 volts in the condenser. Testing the Red with green, and Red with white both registered 27 volts. What could be causing the voltage drop? The contactor does not show any voltage on the coils, but when testing the coil for ohm it shows 12.8 ohm and it also has continuity. The contactor is not sucking in at all. What could be the problem? Thanks for your input.
A service guy came and told me the first stage heat pump does not work because he could not feel the heat when touching the tube. Do you have a video to check which heat pump has problems in the two-stage electric AC+furnace system?
If the heating works and ONLY the A/C won't work, what is the most likely culprit? The thermostats display is fine, as is heat. Do you have a video to diagnose A/C only? I think the fan is fine since heating is working.
Thermostatic expansion valve(TXV hvac)? I've learned that when they fail, that the heat can still work; they are designed to fail that way(generally speaking), so you'll still have heat if it were to happen in extreme cold season. Might not be of any help to you; just thought I'd suggest in case you're still in need, being it came to mind when I read your comment.
acservicetech I have a White Rodgers thermostat that is not working right. I have no control of the temp settings. I touch up or down arrow it goes to 90 by itself. Heat kicks on and run for maybe 2-3 minutes and drop to 62 and eventually cuts off. Is tstat bad? Please help me
Excellent tutorial. I asked a guy years ago how he knew the tstat was failed, he said, 'I jumped it' and I assumed but didn't know that meant (esp with multiple wires, and why). It makes sense if something is simply not turning on. If it starts/stops w/o hitting temp, I assume that is on furnace side?
So my AC and fan work yet my heat (propane) does not. I did the red and green as you instructed and the fan ran so could this be the reasoning behind my heat not working properly? Does this also cause short cycling?
First than everything thanks for the video well explained .. My friend I put the thermostat at 83 this morning and it shutoff all the sistem now it won't start. and nothing in the screen I put new batterys and nothing.
My Lennox Air Handler CBA 27 fan will not come on on circulationg "ON' setting since it was installed 3 years ago. Just running AC from my attic. Would like to circulate the fan all the time. I have even changed out the thermostat. Any thoughts?
Any idea what would cause the blower motor to blow harder once I removed the jumper wire to diagnose the thermostat. My blower kept blowing for about 20 seconds after I pulled the jumper wire and it blew harder than it did when thermostat was working
Is there a follow up video of what to do if this doesn’t work?.. I recently got a new condo.. I installed a “smart thermostat” by EcoBee. It worked fine for a few months but then suddenly stopped. I’ve flipped all breakers, I tried the things in this video.. what is weird is that since it is smart, it will send me notifications when it turns on about the temperature. I will be at work, and out of nowhere (nobody lives in my condo than myself and my cat) it will turn on for like 20 minutes and then go off again..
When you say fan, are you referring to air handler fan or compressor fan? My AC is not getting 24V at contactor to turn on compressor and compressor fan but air handler fan is working. I'm getting 24V b/w R and Y, R and G, R and W on thermostat. When thermostat calls for cool, G and Y goes from open to shorted (connected). So the thermostat is working fine, correct?
@@acservicetechchannel Sir pls i need your help. How do you check sub cooling on a mini split with no service valve on the liquid line. Thanks in advice
So if the minisplit is a vrf then we the manufacturer usually doesn't give us any charging guidelines for it. What I have found though is that in cooling mode when the temp was above 70 degrees, many systems operate at 0-5 degrees of superheat on the full speed emergency cool call. The only reason that they function like that is so the saturated state is arger and they use the accumulator to protect the compressor. In normal units, low superheat would be a big problem for the compressor. The manufacturers just want us to use the total weight method for checking the charge which is a complete recovery, pressure test, find and fix the leak, pressure test again, vacuum, break the vacuum with the total amount of refrigerant that the system says it needs per the rating plate plus additional line set length, thanks
I have a question if you don't mind answering it. I have a Honeywell thermostat, and it would blink like the thermostat was about to turn off completely. So I switched the coin cell battery and when I put the front plate back on to the back part mounted on the wall. I waited for it turn back on, and I put the cool air to auto and on 65. The fan never came on tho, and even when I bring it down to the lowest temp. It would still say "Cool On", but nothing. What could it be? Should I do what you did in the video? I did turn the breaker switch to Off, and then back On and it worked for a min then it shut off. Smh.
Sure is hot in here this summer but im going to miss these low electric bills once i do get the ac fixed one day. Big difference in 250+ per month and 30-40 per month!
If I’m jumping power to check the heating operation I always add the fan into the jump beacause I don’t want any thermal overloads to burn out by turning the heater on without the fan running
Hi and thank you for your videos. I have tried extensively to troubleshoot my thermostat issues but to no avail. The electric furnace works, in so far that if I switch it off from heat to off. If I don't it will just continuously run. I am beginning to wonder if it is a wire issue between thermostat and furnace, as I have replaced the thermostat 4 times in past 5 years. (with same thermostat rth 221). However this year it is not responding to program or hold function. I have five wires coming out (red, white, green, black, and orange.) I don't have pump so orange not in use. I am not sure if relevant but the program and hold feature do work if I remove black wire, but there is no heat when operating with this configuration. Thanks
I have a blank screen on my thermostat. Outside unit, so no drain pan. Thermostat wired to house so batteries not needed. However, the screen comes on when I install batteries. But nothing else happens. But the two snowflake icons flash. This is a 3-year-old PRO1 t701 thermostat with a Comfortmaker unit. What would you recommend I check? It's a hot Saturday night in Texas and having a heat stroke in the past, I don't handle heat well.
The furnace is a TRANE TWV 025 B140A1 May 1994. The problem is no heat. The thermostat is an older mercury switch RHEEM. I would like to check the thermostat for continuity for heat. In the video you say to jumper red to white to check for heat , but how is this done if the green wire cannot now receive power so no fan, no way to check heat from the vents. Confused and would appreciate any advice. BTW cannot find any low voltage fuse for the transformer. ... supposed to be a 3.1 AMP... cannot locate. Shows on the legend, does not show on the schematic. Additional info. Installed a Honeywell non programmable thermostat as suggested by Honeywell. Could not correctly program and they were less than helpful. Re-installed the RHEEM mercury Thermostat. Same condition. Also replace Time delay fan manger.. Limit switch checks ok. This is why we suspect the T'Stat. Do you concur this may be the T'Stat ? Or? Baffled. Thanks.
The only way to get my heater to kick on is to change the fan selector from AUTO to ON. Then when the desired temp is reached I change it back. But then it wont kick on again when the temp drops. Should I just replace the thermostat?
Sesha Chary, I am very appreciative that you chose to Support the ongoing work of AC SERVICE TECH through Patreon! Feel Free to email me any questions you may have at info@acservicetech.com also let me know what questions you would like answered or shown in the quarterly Insider video, thanks!
I just have a red and white wire. I only have heat so that should explain it, right? My panel “works” meaning it can be set etc, however it has no impact on the furnace. If the heat is on it keeps staying on... and temp keeps rising. Any suggestions?
i put a new thermostat this summer honeywell RTH111 it work well , i try to turn on the heater today i hear the gas came on but the fan is not working or do i need to wait a little bit and the fan came on
If the furnace is trying to turn the heat on then it is receiving the signal from the thermostat. It is past that and in the furnace. It sounds like maybe with the power off the capacitor should be tested or at least a tech will start there if the blower motor is not coming on. This one would test with the power off. ---- ruclips.net/video/flbUtLMeSOQ/видео.html
My thermostat is set for 60 degrees at 3 am. The thermostat still runs at 68. Is the thermostat unrepairable? How long does a thermostat last? 10 years?
For residential home with local thermostat. Possibly a schedule for the cooling on the thermostat.. 1 yr later and no one could comment their best guess. Comments are greatly welcome
The ac with cold air keeps running after reached setpoint? If just fan is running blowing normal return space temp air, then blower probably has a schedule. Or the contacts themselves are bad in the thermostat and the unit shuts down late at night due to low pressure/ low limit with cold outside air. Then resets the next day
I have a rookie question for ya. I have two Lennox units in my house. The upstairs one is 2.5 tons and the downstairs is 2.0 tons. Why is it that the 2 ton outdoor unit is larger than the 2.5 ton outdoor unit? The 2 ton unit calls for 16 degrees subcool and the 2.5 calls for 6 degrees.
I just put in a new condensate pump. Pretty simple. Turn off the power, unplug the old little giant and remove. Install new little giant, plug in and power up. Problem is that after doing this I have no power to the thermostat. I jumped the fan but it doesn't run. It's a tempstar and I don't believe there is any reset switch. I have checked fuses and breakers and all are good. I filled the reservoir and the pump works. The pan is not switched for water. The fan just hums. I checked the capacitor and it shows 7.3. Any idea where to look next?
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Fieldpiece TC24 Temp Clamp amzn.to/2qHLyjZ
Yellow Jacket Refrigerant Gauge Set amzn.to/2aenwTq
Refrigerant hoses with valves amzn.to/2aBumVI
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so before i do anything, i should shut off power to house right? so i dont get electrocuted? then open the panel display? I have a honeywell CT500 that goes blank every so often and now not generating cold air...i have a brand new AC unit too. it has no batteries, so that cant be the problem. i also reset the circuit breakers and the display panel of thermostat still goes blank and then re-appears. it does this every few minutes or so. is it a problem with the wire connection of thermostat? is it loose?
I recommend calling a tech but they would shut the power to the hvac system off and take the tstat face plate off and tighten the connections on both ends, in the thermostat and in the furnace or air handler. After that they will check for 24v to the thermostat and if they have it then it is a bad thermostat. It could also be one of the pins not aligning on the back of the thermostat.
did u power off the thermostat? i see nothing on the panel at the beginning of vid.
How to replace thermostat for boiler heater
How to replace thermostat for boiler heater
Thank you for saving me a costly service visit! Your suggestion of tapping the R and G wires helped me confirm a bad thermostat! Thank you for taking the time to produce easy to follow instructional videos with detailed explanations that don’t require hvac training to understand!
Glad it helped!
Hi---It looks like you understood what he said about the red and green wire. Did he say the thermostat is bad if the fan DOES come on when touching the red and green wires together or if the fan DOESN'T come on? Thanks for your help. Jesus bless.
@@sandrarichardson2713 Hi! He said if the fan turns on when you jump the R and G, then the faceplate/thermostat is bad. Good luck!
My man!!!!!!!! After I changed almost everything in the furnace, not works until I did the test G and R and the thermostat was bad . Now my furnace work like 7/11 store non stop. Thank you so much bro
The best instructor on RUclips... he makes it so easy to understand.
Thank you very much Dwayne Wallace! I am glad you appreciate the video!
For anyone who's control panel is working and whose unit is fine but doesn't seem to be sending data: If continuity from the screws to the copper is good, look at the AC unit's circuit board and check the fuse(should be purple or amber). I accidentally blew it somehow when moving the thermostat. Easy fix!
Thanks! You saved me so much time. Couldn’t figure out what my problem was!
I’m having intermittent thermostat issues. Going to replace it tomorrow am when the store opens. I appreciate the video, it confirmed what I had done.
Thanks for letting me know!
Awesome, I just completed tech school last fall and I'm working for an HVAC contractor! ALWAYS learning!
Great to Hear and in this trade, we all will always be learning! Keep it up because over time you will move up the ladder right past those that stop searching for answers and learning new things! Thanks
So they didn’t teach you this on the school 😮.
i enter youtube to look for thermostat problems, cause i got a service call for tomorrow, boom this video give me all i needed. ty
Looking at this video while doing a service call lmaooo
*Easy to assemble **Fastly.Cool*
Thank you I’ve literally watched atleast 2 videos every day and I’ve become a better tech because of you thanks a lot I have to get better at gas furnaces and diagnosing electrical issues
That is awesome to hear Will! Thanks for letting me know!
I just solved my problem with my 1950"s Lennox Furnace with this video. Thank you for all the great videos!
Thank you so much for helping me bring heat back to my home for my family!
The explanation and demonstration is so very clear and Very much appreciated, Thank You!
Great video and a good explanation of why the industry moved away from the old mercury switch. Those switches would bounce those compressors on and off until the mercury settled. A five minute delay is a bit long but better safe than sorry.
Yes if I need to turn it on quickly then I use the mag jumpers, otherwise I have time while doing other maintenance, Thanks
I been seeing your videos for 2 years before I became a tech , and even now I always see them and learn dude . Ur a great teacher , I can only image how your helpers or family members who are intrested in the trade turns out to be man . Thanks and please always keep uploading more videos .
Thank you very much Gabriel!
Another way I have done it. I used the pins on the back of the thermostat battery operated type. Call for blower the pins should ohm out. Same thing for calling for heat. Make sure you are connecting to the correct pins because they are not marked you have to reference how the pins plug into the back plate.
Thank you for the wonderful videos. I have an issue I am troubleshooting, if you can chime in. IFB sends 24v to the condenser every three minutes regardless of the indoor temperature reaching to the set temperature on the thermostat. Air handler and blower fan keeps running blowing warm air through vents after outdoor unit is off and until compressor engages again in three minutes. So the condenser fan and compressor are on for three minutes and off for three minutes. Subcooling on the unit checks out fine using liquid line pressure and temperature so not suspecting high or low pressure in the system. Contactor leads receive 24v every three minutes. I have checked the main and fan control board for damage or loose wires. This short cycling is not as bad but I think I have an issue I can figure out. Thank you in advance!
This video was a BIG help! Thanks for posting it!
I had a call where the AH was running but the condenser was not. I had no voltage between C and Y at the control board outside or the AH. Pulled out the Tstat and jumped between R and Y and the system came on. Tstat was bad.
Good Stuff, My pro TH8000 on Cool or fan, the heater turns on. This test should expose issue that I believe is 25 yr thermostat
Awesome. Girl Power. You helped me figure it out. I GOT HEAT. I so refused to call service man. I knew if air conditioner worked and I tested just like you showed to boot the fan, then I knew it wasn't the furnace. I have where red wire could go either to RC or RH, it was at RC so I hooked red to RH and I got heat. Thank you
I have RC and RH. How did you test the thermostat?
Even though you now have heat, that's not really the proper way to do that. You shouldn't have to constantly switch your live wire over every time you want to switch between heating and cooling. If you only have one red wire coming in from furnace control board, it should be hooked into the RH terminal, while a separate jumper wire should be connected between RH and RC.
Thank you, I was able to fix my AC problems using this video, thanks for taking the time
Awesome to hear, thanks!
This helped me out tremendously! Thanks alot
Thank you so much for a concise clear video on troubleshooting.
Thanks Josh!
So clearly explained and helpful. Thank you so much.
Lets me know if I should call our utility that installed the energy saving thermostat or if it's time to call an AC tech without wasting his time or mine.
That is great to hear, thanks
Do you know if having the capacitor changed on an exterior HVAC unit would cause the thermostat to behave differently on both heat and cool?
For example, I had the heat set at 69, was cold this morning, so bumped it up to 70. Waited a few seconds, nothing. Bumped it up to 71, it started immediately. Room temp when finished was 70 though, measured by a refrigerator thermometer I had balanced on top of the thermostat.
Another example, AC was set to 73, and I dropped it to 72. At 72 (the desired temp), unit kept running. End temp was 72, according to that refrigerator thermometer, but it normally would have shut off once the thermostat read 72, not kept running.
There have been maybe 15 second delays for the unit to kick on after changing temps, though I swear I could hear the one in the basement kick on immediately when I was playing with it last night, just not the exterior unit.
I've been playing around quite a bit with it, so I forget what's what. I just know the unit would kick on immediately with any temp adjustment, up or down, even if I switched directly from heat to cool or cool to heat right away. It's a forced air electric heat pump, if that matters. I almost wish he hadn't changed the capacitor because I liked the way the thermostat used to behave. I even went out and bought a new thermostat, the same one, $100, that I plan to install myself today, just so that they don't charge me $400 to install theirs when another place comes by tomorrow. Actually, that was the price they quoted to install mine. I don't want them telling me something else is wrong, if there isn't. Plus, I need to see how a brand new thermostat behaves so that I know what to tell them.
Before jumpering the R and G, I would use a multi-meter and check for 24V A/C between the R and C.
Yes, sometimes there is no C to test from though, thanks Eric S!
@@acservicetechchannel Was just going to say, that method wouldn't do you any good for a thermostat with batteries..
Thanks - just tested mine and it was, indeed, the thermostat - fixed and back to cool for $25.
Awesome, thanks!
I know this is an old video but, I only have a red and white wire going to my thermostat. When I turn the heat on for my thermostat the boiler runs for a while and then shuts off. A couple minutes later it kicks back on and so on. It just keeps running like that no matter what the heat it set on. You can have it set to 60 and the temp will keep climbing...We've replaced the thermostat with the same one like three times and still get the same outcome. I just turned the boiler off and touched the red and white and turned the boiler on and it kicked on. I've had a couple people look at it and nobody has an answer.
Hi. The screen on my thermostat is blank. I replaced batteries, nothing. A couple days was back on. Now blank again…but, if I press the temperature up, it comes on (not the screen, the furnace). Also, if I turn fan on it comes on. Any ideas 💡. Thanks so much.
Great video! It is to the point and easy to understand. Thanks!
Thanks Josh!
Thank you for this video, the logical path you have laid out, though not exactly the issue I had, it helped me draft my own plan and it helped me diagnose my issue. I was getting 24V at the thermostat, and at the circuit board at the air-handler in my basement. I can hear the thermostat click when I switch to AC or Heat. Heat came-on (this was summer and 80 F Day so I had to set the thermostat to 82 or something to get it to work, but it worked, the AC however did not. Knowing that I got 24V (my meter showed about 27v), so I knew volts should be going out to condenser outside. But the condenser did not start. I saw no 24V at the contactor. I pushed the contactor and it started, condenser and I held it there for a few minutes and family inside confirmed getting cold air, so I knew no issues with the condenser/ compressor. So basically the issue was between the wire that came out of air-handler to the condenser outside. I started following the 24V wires from the contactor to the wall, and I found the issue. I should have looked for this as soon as I found a mice nest in the condenser, they had chewed one of the 24V wires and thus contactor did not get the juice it needed to kick-in the condenser. Once I patched the wire, everything was working again.
I have seen folks ask where to buy some of the electrical parts (Contactor, Transformer, Capacitor, etc.) I found these on-line, but you have to wait for a few days, alternatively if you need one quickly I was able to buy at Grainger that is not too far from me, and a GPS (General Plumbing Supply) they had some of the parts I needed as well. This is just an FYI.
Glad to hear, thanks!
Thank you for sharing your knowledge brother ! You’re a great Teacher and Tech!
Thanks a lot Darin!
Outstanding. Great work
Thank you very much!
Question about colors of wire and the location on what letter the colored wire is placed.
On my thermostat there is not a yellow wire. Only red, green & blue.
Red on R
Green on G
Blue on Y
No wire on W
When I check with the wire red & green my fan does turn on. If I understand correctly that means it’s my thermostat front that needs replacing.
I may have screwed up the compressor by checking (R) and blue (Y). Is it the letter location that matters? Or, did I wreck something by checking Y & R because Y has the blue wire?
My air conditioner is controlled thru the thermostat. The Rc is the AC? If so how come there is not a colored wired attached?
Ii know that G is my fan and it turns on.
As shared I tried R & Y and nothing happened;
I don’t know where to check the AC unit either only having 3 wires versus 4.
Thank you very much for your video. My system was keeping running when both inside and setting temperatures are matched, what is caused the problem inside the air-handler, need help?
I have a 2 wire Carrier edge thermostat- any way to test that?
My furnace wouldn't turn on, and I realized that the problem started after I had changed the thermostat batteries. Checked the thermostat wiring and thought that the excess dielectric grease that was on the male and female terminals was causing a problem, then realized that because of the awkward location where the thermostat
was mounted, that the display portion of the thermostat hadn't fully seated all the pins. If you didn't look at it closely, you couldn't see it wasn't seated.all the way It allowed me to run the fan, but not run anything in auto, therefore no call from the thermostat. Motto: Make sure the face plate is fully and evenly seated.
Hello Craig. I was working in the field and ran across a thermostat that the voltage on the R and Y was 16 volts, it also showed 16 volts in the air handler and 16 volts in the condenser. Testing the Red with green, and Red with white both registered 27 volts. What could be causing the voltage drop? The contactor does not show any voltage on the coils, but when testing the coil for ohm it shows 12.8 ohm and it also has continuity. The contactor is not sucking in at all. What could be the problem? Thanks for your input.
A service guy came and told me the first stage heat pump does not work because he could not feel the heat when touching the tube. Do you have a video to check which heat pump has problems in the two-stage electric AC+furnace system?
If the heating works and ONLY the A/C won't work, what is the most likely culprit? The thermostats display is fine, as is heat. Do you have a video to diagnose A/C only? I think the fan is fine since heating is working.
Thermostatic expansion valve(TXV hvac)? I've learned that when they fail, that the heat can still work; they are designed to fail that way(generally speaking), so you'll still have heat if it were to happen in extreme cold season.
Might not be of any help to you; just thought I'd suggest in case you're still in need, being it came to mind when I read your comment.
Thanks Helps a lot.
Glad it helped
Awesome video. Good teaching tool ...please keep up the good work ...
Thank you very much!
acservicetech I have a White Rodgers thermostat that is not working right. I have no control of the temp settings. I touch up or down arrow it goes to 90 by itself. Heat kicks on and run for maybe 2-3 minutes and drop to 62 and eventually cuts off. Is tstat bad? Please help me
Do you have anything that shows what wires should be connected at the furnace from the thermostat to the fan motor ?
What’s wrong when the thermostat works on fan only ? When put on auto the ac and the heat don’t work. It does nothing, no sounds or anything
If you need heat in an emergency, would you have to connect the three wires (r g w) altogether? Or will just jumping the r & w work?
Excellent tutorial. I asked a guy years ago how he knew the tstat was failed, he said, 'I jumped it' and I assumed but didn't know that meant (esp with multiple wires, and why). It makes sense if something is simply not turning on. If it starts/stops w/o hitting temp, I assume that is on furnace side?
Thanks
No problem
So my AC and fan work yet my heat (propane) does not. I did the red and green as you instructed and the fan ran so could this be the reasoning behind my heat not working properly? Does this also cause short cycling?
If I wanted to check the heat I guess I would have to jump the Red and White?
First than everything thanks for the video well explained .. My friend I put the thermostat at 83 this morning and it shutoff all the sistem now it won't start. and nothing in the screen I put new batterys and nothing.
Did you check to see if you have 24v on the indoor unit from r to c? It is possible the power at the indoor unit is off or fuse is blown, thanks
Yes I do the thermostat was the problem. I buy another one of the same i just put the new in it problem solved..thank you very much for your help.🙏🙏👍👍
My Lennox Air Handler CBA 27 fan will not come on on circulationg "ON' setting since it was installed 3 years ago. Just running AC from my attic. Would like to circulate the fan all the time. I have even changed out the thermostat. Any thoughts?
Again another great video...
Thanks Robert!
I appreciate this video man. I'm relatively new to the trade so thermostats always scared me lol
Any idea what would cause the blower motor to blow harder once I removed the jumper wire to diagnose the thermostat. My blower kept blowing for about 20 seconds after I pulled the jumper wire and it blew harder than it did when thermostat was working
Is there a follow up video of what to do if this doesn’t work?.. I recently got a new condo.. I installed a “smart thermostat” by EcoBee. It worked fine for a few months but then suddenly stopped. I’ve flipped all breakers, I tried the things in this video.. what is weird is that since it is smart, it will send me notifications when it turns on about the temperature. I will be at work, and out of nowhere (nobody lives in my condo than myself and my cat) it will turn on for like 20 minutes and then go off again..
very practical video, thank you ...
Thanks Pei Broker!
Do you have a video if the fan Doesn’t come on, where to look next?
When you say fan, are you referring to air handler fan or compressor fan? My AC is not getting 24V at contactor to turn on compressor and compressor fan but air handler fan is working. I'm getting 24V b/w R and Y, R and G, R and W on thermostat. When thermostat calls for cool, G and Y goes from open to shorted (connected). So the thermostat is working fine, correct?
Believe or not sir, you are the best
Ha ha, thank you very much Chick. I am glad you enjoy the videos!
@@acservicetechchannel Sir pls i need your help. How do you check sub cooling on a mini split with no service valve on the liquid line. Thanks in advice
So if the minisplit is a vrf then we the manufacturer usually doesn't give us any charging guidelines for it. What I have found though is that in cooling mode when the temp was above 70 degrees, many systems operate at 0-5 degrees of superheat on the full speed emergency cool call. The only reason that they function like that is so the saturated state is arger and they use the accumulator to protect the compressor. In normal units, low superheat would be a big problem for the compressor. The manufacturers just want us to use the total weight method for checking the charge which is a complete recovery, pressure test, find and fix the leak, pressure test again, vacuum, break the vacuum with the total amount of refrigerant that the system says it needs per the rating plate plus additional line set length, thanks
@@acservicetechchannel great
I have a question if you don't mind answering it. I have a Honeywell thermostat, and it would blink like the thermostat was about to turn off completely. So I switched the coin cell battery and when I put the front plate back on to the back part mounted on the wall. I waited for it turn back on, and I put the cool air to auto and on 65. The fan never came on tho, and even when I bring it down to the lowest temp. It would still say "Cool On", but nothing. What could it be? Should I do what you did in the video?
I did turn the breaker switch to Off, and then back On and it worked for a min then it shut off. Smh.
Very helpful,,,thanks
Sure is hot in here this summer but im going to miss these low electric bills once i do get the ac fixed one day. Big difference in 250+ per month and 30-40 per month!
Last night was only night 3 for me.. running the fan on myself wasn’t so bad even though it was 86 in here (Florida)
Thank you! Info helped diagnose the thermostat.
Glad to help Andrew!
I learned alot. Thank-you!
thanks this video helped us at our home
Thanks Mike!
If I’m jumping power to check the heating operation I always add the fan into the jump beacause I don’t want any thermal overloads to burn out by turning the heater on without the fan running
Hi and thank you for your videos. I have tried extensively to troubleshoot my thermostat issues but to no avail. The electric furnace works, in so far that if I switch it off from heat to off. If I don't it will just continuously run. I am beginning to wonder if it is a wire issue between thermostat and furnace, as I have replaced the thermostat 4 times in past 5 years. (with same thermostat rth 221). However this year it is not responding to program or hold function. I have five wires coming out (red, white, green, black, and orange.) I don't have pump so orange not in use. I am not sure if relevant but the program and hold feature do work if I remove black wire, but there is no heat when operating with this configuration. Thanks
Thanks very useful ❤️🙏
Thanks a lot
I have a blank screen on my thermostat. Outside unit, so no drain pan. Thermostat wired to house so batteries not needed. However, the screen comes on when I install batteries. But nothing else happens. But the two snowflake icons flash. This is a 3-year-old PRO1 t701 thermostat with a Comfortmaker unit. What would you recommend I check? It's a hot Saturday night in Texas and having a heat stroke in the past, I don't handle heat well.
You would need to check the 3 or 5 amp fuse in the outdoor unit after turning the power off. test from r to c with a multimeter for 24v, thanks!
The furnace is a TRANE TWV 025 B140A1 May 1994. The problem is no heat. The thermostat is an older mercury switch RHEEM. I would like to check the thermostat for continuity for heat. In the video you say to jumper red to white to check for heat , but how is this done if the green wire cannot now receive power so no fan, no way to check heat from the vents. Confused and would appreciate any advice. BTW cannot find any low voltage fuse for the transformer. ... supposed to be a 3.1 AMP... cannot locate. Shows on the legend, does not show on the schematic. Additional info. Installed a Honeywell non programmable thermostat as suggested by Honeywell. Could not correctly program and they were less than helpful. Re-installed the RHEEM mercury Thermostat. Same condition. Also replace Time delay fan manger.. Limit switch checks ok. This is why we suspect the T'Stat. Do you concur this may be the T'Stat ? Or? Baffled. Thanks.
Great video. Thanks for the help
Thanks Mike!
Thanks for the awesome video bud!!
Glad to help chingonyayo!
Do have to turn power off for to see if fan come in
Baahahaha turns out mine just had dead batteries with corrosion on one of the terminals! LOL
To the point and direct, great job keeping it simple!
Thank you very much, glad you enjoyed it! Here is the playlist for thermostats if interested----ruclips.net/p/PLxnHR5_D2ojzDfU1IjPpzdhi_mUGe3F7W
Great video... thanks
Thanks Charolito1312!
thank you very much SR. you are the man!!!
I am glad you enjoyed the video Luis!
Do you have a video on testing the thermostat wiring for shorts and or breaks?
Yes I do believe. Look through the "acservicetech Thermostat Troubleshooting Playlist" for the videos there, thanks
Thank you sir
Glad to help Vjn!
At 4:48 you said if the fan not come on do you mean fan blower or condenser fan?
Thanks for the question. I am referring to the blower motor only turning on. Thanks
The only way to get my heater to kick on is to change the fan selector from AUTO to ON. Then when the desired temp is reached I change it back. But then it wont kick on again when the temp drops. Should I just replace the thermostat?
Nice
Thanks
very educative thank you. regards
Thanks Sesha!
Sesha Chary, I am very appreciative that you chose to Support the ongoing work of AC SERVICE TECH through Patreon! Feel Free to email me any questions you may have at info@acservicetech.com also let me know what questions you would like answered or shown in the quarterly Insider video, thanks!
I just have a red and white wire. I only have heat so that should explain it, right? My panel “works” meaning it can be set etc, however it has no impact on the furnace. If the heat is on it keeps staying on... and temp keeps rising. Any suggestions?
Good video. But there are alot of different thermostats. This one is the easiest to work on.
Thanks Colt 45 zag!
@@acservicetechchannel thank you. I refer back to your videos just to refresh my mind sometimes. Always good in detail! 👍
How about if the batter is running low would that make it not read right
i put a new thermostat this summer honeywell RTH111 it work well , i try to turn on the heater today i hear the gas came on but the fan is not working or do i need to wait a little bit and the fan came on
If the furnace is trying to turn the heat on then it is receiving the signal from the thermostat. It is past that and in the furnace. It sounds like maybe with the power off the capacitor should be tested or at least a tech will start there if the blower motor is not coming on. This one would test with the power off. ---- ruclips.net/video/flbUtLMeSOQ/видео.html
My thermostat is set for 60 degrees at 3 am. The thermostat still runs at 68. Is the thermostat unrepairable? How long does a thermostat last? 10 years?
What causes the ac to keep running when thermostat temp reaches but it’ll cut off at night when outside temp cools down?
For residential home with local thermostat. Possibly a schedule for the cooling on the thermostat.. 1 yr later and no one could comment their best guess. Comments are greatly welcome
The ac with cold air keeps running after reached setpoint? If just fan is running blowing normal return space temp air, then blower probably has a schedule. Or the contacts themselves are bad in the thermostat and the unit shuts down late at night due to low pressure/ low limit with cold outside air. Then resets the next day
I have a rookie question for ya. I have two Lennox units in my house. The upstairs one is 2.5 tons and the downstairs is 2.0 tons. Why is it that the 2 ton outdoor unit is larger than the 2.5 ton outdoor unit? The 2 ton unit calls for 16 degrees subcool and the 2.5 calls for 6 degrees.
The 2 ton is likely a higher SEER rating than the 2.5 which means it is bigger to be more efficient in terms of heat exchange on the coils, thanks
Good
also If the reversing valve solenoid was beginning to short out would it fry the defrost board or the thermostat? its a lennox 13hpx-030-13
I just put in a new condensate pump. Pretty simple. Turn off the power, unplug the old little giant and remove. Install new little giant, plug in and power up. Problem is that after doing this I have no power to the thermostat. I jumped the fan but it doesn't run. It's a tempstar and I don't believe there is any reset switch. I have checked fuses and breakers and all are good. I filled the reservoir and the pump works. The pan is not switched for water. The fan just hums. I checked the capacitor and it shows 7.3. Any idea where to look next?
So if you jump the 24v wire to the g wire and it turns on (thermostat is set to auto not fan), that means the thermostat is bad ?
great info
Thanks Thul kiful jones!
The fan? The blower or condensor fan?
Super. An easy one!
Thanks NMranchhand!
I’m reading 24 volts between R&Y , R&W , but only 12 volts between R&G. Could it be a transformer issue? Or a short on the G ?
Thank you!!!
Thanks jimmy ung!