Heat Pump Troubleshooting- Defrost Board Testing and Bypass for Cooling!

This HVAC Video is about how to Troubleshoot a Heat Pump Defrost Board and How you would bypass the board for Cooling and why you would not bypass it for Heating. I cover where to test for 24v, where the 24v is coming from, what wires you need to connect to get cooling on, when the reversing valve is powered, as well as other tips. Supervision is needed by a licensed HVAC Tech before doing this as Experience and Apprenticeship garners Wisdom and Safety.
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
Related Videos
• DEFROST Control Board ...
• Air Handler Control Bo...
• Heat Pump Thermostat W...
• Air Handler with Elect...
• HEAT SEQUENCER Operati...
• HVAC Thermal Limit Swi...
• Heat Pump Fan not Runn...
• Heat Pump Defrost Ther...
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
Our HVACR Educational Books, E-Books, Workbooks, Cards, Posters, and PowerPoints:
All Our Educational Products on Our Site: www.acservicetech.com/store
All Our Educational Products on Amazon: amzn.to/48pDd82
Mini Split Book and E-Book on Our Site- www.acservicetech.com/mini-sp...
Mini Split Paperback on Amazon- amzn.to/3ytHJSs
Mini Split Paperback on TruTech Tools- www.trutechtools.com/BooksGui...
Refrigerant Charging Book and E-Book: www.acservicetech.com/ac-book
Refrigerant Charging Paperback on Amazon: amzn.to/46xTeHf
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
Our HVACR Online Resources!
Our HVAC Calculators: www.acservicetech.com/hvac-ca...
Our Newest Articles: www.acservicetech.com/articles
Try our HVAC/R Quizzes! www.acservicetech.com/quizzes
Our Other Resources: www.acservicetech.com/resources
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
Tools Used in Our Videos!
Tool Links on Our Site: www.acservicetech.com/tools
Our Tool List on Amazon: www.amazon.com/shop/acservice...
Support the Channel by purchasing tools through TruTech Tools!
Use this link www.trutechtools.com/?aff=8
Save 8% at checkout using code "acservicetech"
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
Follow Us On Our Social Media & Podcasting Channels!
Patreon: / acservicetech
Facebook: / acservicetech
Instagram: / acservicetech
X: / acservicetech
LinkedIn: / ac-service-tech-llc
Tiktok: / acservicetech
Spotify: open.spotify.com/show/74KXLz5...
Apple Podcasts: podcasts.apple.com/us/podcast...
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
⚠️ Disclaimer:
Information in this video is intended for educational purposes only. Any work related to the topics in this video should be performed by licensed technicians or by apprentices under the supervision of licensed technicians. AC Service Tech LLC is not responsible for any possible damages or injuries caused by the use or misuse of any information provided.
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
#hvacr #hvacr #hvactrainingvideos #hvactraining #hvactraining101 #acservice #acservicetech #heatpump #explain #heatpumps #airhandler #wiring #thermostat

[@acservicetechchannel]

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) Here is the Link for the newer UEI DL479 Multimeter with temp sensor- amzn.to/2jtsUbJ Here is the Link for the newer UEI DL469 Multimeter- amzn.to/2jw4ePJ Here is the Link for the UEI DL389 Multimeter used in the video - amzn.to/2naJr9o Here is the link for the Irwin Wire Stripper/Cutter/Crimper amzn.to/2dGTj2V Here is the link to the Fieldpiece SDMN6 Dual Pressure Testing Manometer with Pump-amzn.to/2jyK5Ka Here is a link for the Supco Magnet Jumpers amzn.to/2gS4h6z Other tool links can be found in the video description section. ACSERVICETECH is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.

[@johncameron2930]

To

[@anthonyfernandez916]

acservicetech where The T1 and Y where those wire come from please help

[@acservicetechchannel]

Anthony, if the unit is not a Ruud, Rheem, Weathermaker then take your y from the air handler and connect this to one of the two wires coming from the safety pressure switches, then take the other wire coming from the safety pressure switches and attach to one of the reversing valve wires and one side of the contactor. Then connect the other side of the contactor and the other wire from the reversing valve and attach this to the c wire from the air handler. This way you keep the safety wires intact. This is just for cooling for a day or two until you get the defrost board back in or switching from use as a heat pump to ac only if the board is bad, thanks

[@anthonyfernandez916]

acservicetech thank you for answering my question been in the industry for one year

[@acservicetechchannel]

Glad to help Anthony!

[@F33Nominal]

As old as this video is, I must say...it is still saving lives over here! My wife noticed the thermostat was out. Oh boy...here we go! Mind you, I am no AC service tech, but just a homeowner with a handy knowledge of the trades. Noticed a fuse blown in the air handler. Let's hope it was a one off and change it. POP again! Looks like we have to chase down an LV short. Pull the thermostat and removed the terminations hoping it was a bad thermostat. Used these wires to isolate the condensor LV wires and found the yellow wire to the condensor to be the faulty one. Tested both cables to the thermostat and the condensor and both are good! There goes the easy fix....now i am in the condensing unit. Found a circuit board and thought it was game over. I started to remove the thermostat wires one by one from the board (which I later identified as a defrost control board), and after blowing through several fuses, I found the yellow wire to blow the fuse everytime it was plugged into the spade terminal. Now I was done...my first assumption was that the defrost board was bad and now we are just going to have to ride out the night in Florida heat with temperatures inside at 80 degrees. My wife and daughter were sleeping so peacefully but sweating as the temperature was rising. As much as i wanted to do something about it, i felt as if my hands were now tied until i can replace the board, but getting through the night was being Did some research looking to buy a new board and stumbled across your video WITHOUT even thinking that bypassing was a temporary option. Although the system was different, the theory behind it all was the same. Needless to say, I was able to fix this for the night due to your in-depth and detailed explanation of what you were doing. We are now at 76 and dropping. To find a new board is the next move. Will my family suffer tonight? No! Thanks to you for the knowledge and direction you provided! Without it, my family would be miserable tonight. That is no longer the case and I thank you again for it!

i hear you man, i just found it now myself it is 2024 jan. but i wish this was a rheem unit, he was showing here. he said that the rheem unit functions different in cool mode that the other mfg, units. So, i am trying to figure out what the rheem units do in the heat mode now, my out door unit is NOT COMING in either heat or cool, but the indoor blower unit is running ok for now.

[@rodballen2331]

this is the best hvac channel ive seen so far.

[@acservicetechchannel]

Thanks so much Rod!

[@rodballen2331]

acservicetech im going to school for this and these videos help alot thanks

[@acservicetechchannel]

That's great to hear. I am a high school and adult HVACR teacher and I have had my business for some years now. This field has always treated me and my family very well. Those that ask questions and have initiative will go far.

[@jimmyjean6663]

I am so bless everytime I'm watching your video. You make me a better tech from your teaching.. i pray God for you to continue adding more knowledge to your brain, therefore you can always share to other people.. May God bless you as always...

[@jamesblack3429]

I've watched a lot of his videos and they are all on point and very thorough. He doesn't half ass things and take shortcuts. Done properly, great job bud.

[@acservicetechchannel]

Thanks a lot James!

[@MkShantrul]

I went to tech school for this but went straight into the building maintenance field not working with this everyday so when I do get a chance too I am not always real confident in myself watching your videos helps bring back things I forgot or things I never ran into yet that you only get in the field and repetition of doing this type of work thanks sir.

[@acservicetechchannel]

Thanks msmolik14!

[@neomacchio4692]

Also thank you! For now, thanks to your video I got my AC working in FL 90deg heat. It’s only going to get worse.

[@NDProps]

You just told me everything I needed to know to fix my unit. Thank you so much. Appreciate you.

[@acservicetechchannel]

You are so welcome

[@MannyFontes1968]

Dude, this video is on point with this bypass you did for cooling. Very thorough explanation and in detail...

[@acservicetechchannel]

Thanks Manny, this is just a temporary bypass. If you were to keep it like this for an extended period, make sure to include the pressure switches in series with the 24v hot to the contactor, thanks!

[@MannyFontes1968]

@@acservicetechchannel you're welcome and I need your help again. My neighbors unit is a complete Rheem system and it stopped cooling a few days ago and I tried doing the bypass but it didn't work like yours did. I did find that the reversing valve and the contacter was not getting the 24v from the defrost board but once I jumped it from the red wire to the contacter and disconnected the 24v side of the rev valve, the system started cooling. It worked for about an hour and half to cool the house to the set temp of 77, but it didn't start up again. I haven't looked at it again but i think it's the contacter that didn't close. I ended up reconnecting all the wires to how it was before and just jumped power to the contacter. Also, the common brown wire color coming from the thermostat doesn't work like it should when it gets to the defrost board. You have to switch it to the blue wire for it to work. This doesn't make sense to me since the schematics show the brown wire as the common. Sorry for the long story.

[@acservicetechchannel]

Rheem powers their reversing valve during heating instead of cooling. The one in the video was a carrier one, thanks

[@michaelcostello6991]

A wiring diagram would help a lot for newbies. If you had this on the video that you could reference while you work.

[@acservicetechchannel]

Thanks for letting me know Michael!

[@acservicedaytona386portora3]

Explained very well, You do a lot for us, thanx for all the videos, you got a lot on your plate,With work and school, and finding time to do videos..good job. I'm still happy with all that you do.

[@acservicetechchannel]

Thank you very much Robert!

[@cecillittle4737]

Thanks for the Video. I had 24 vols=ts on the control but not at the contacter. As soon as I touched and moved one of the wires going from the contacter, the contacter engaged and everything started working!!! I cleaned the stake-ons and am hoping for the best. Thx again Cecil from Florida

[@acservicetechchannel]

Thanks

[@borshardsd]

Great content. Beautifully timeless. Old or new videos from you guys its the same excellent delivery 👏

[@Pretzel114]

Nice one ACSERVICETECH. I hope I get a chance to work more on heat pumps so i can put this stuff to use. But till then at least I have the knowledge and can be ready. Thanks again

[@acservicetechchannel]

I am sure you will! Thanks

[@teklesenbetgebreamlak7365]

I WOULD Like to say thankyou lam new technicial to the industry but with your video lam getting more confidence now troubleshooting.

[@acservicetechchannel]

That is really great to hear! Thanks!

[@jimmyung3212]

You are the king of hvac channel!!!

[@acservicetechchannel]

I am glad you are enjoying each of the videos jimmy!

[@user-vb8jl6nf4k]

Totally agreed

[@pinero155]

Just wanted to say thank you for this very informative video, definitely saved me and I appreciate it thanks once again

[@bass3man2u34]

Thank you so much, you videos are great and easy to understand. thank you again so much for sharing your knowledge. you're awesome dude.

[@acservicetechchannel]

Thanks bass3man 2U!

[@jimmyjean6663]

Good teaching.. Sir, may God bless you with more knowledge as long as you live on this Earth... you help a lots of new tech out there without knowing. Jesus loves for that

[@acservicetechchannel]

May The Lord Bless You Too Jimmy!!!

[@musicjunkiesstudio]

Thank you . Your video really helped me. Thks for doing what you do.

[@acservicetechchannel]

You are so welcome

[@contextkey9913]

This was quite helpful. Thank you

[@maxxdanero]

Quality teaching!

[@alsur272]

Thank you for useful tutorial video ACSERVICETECH, good job!!! Could you add wiring schematic diagram in description of this video. It would be make even more sense.

[@eracismm]

I thought the same, great video Craig.....

[@ronmason5861]

Makin it simple. Thank you

[@jesuscastillo1083]

Why cut wires from reversing valve simply disconnect them from difrost board and attach direct to contractor?

[@divmart8378]

Esse rapaz é o melhor 👏👏👏👏

[@floridascratcher6190]

ameristar reversing valve works like rudd and rheme also. just fyi. great video and great instructions. i like every video you do

[@Froggability]

The de-ice I'm familiar with is so much simpler. On sensing Low temp, just lifts the neutral to: reversing valve, indoor fan, outdoor fan. Compressor continues running. Machine jumps into cooling, condensor melts ice, either for 20 min timer or till temp rises. Then switches back.

[@beemikeme]

Thanks for spending the time to make all of your videos. I have watched many of them. You are one heck of an EXCELLENT teacher clearly explaining everything you are doing! I have a heat pump that is not cooling. The low side pressure is about 50 psi and the high side is about 150 psi. Both lines get neither warm nor cold. The indoor fan, outdoor fan and compressor are all working. Do you think the defrost board is causing the lack of cooling? Thank you, Mike

[@acservicetechchannel]

Hey Mike it seems that 50 psi would be too low and that you are low on refrigerant. You would check in subcooling if you have a txv metering device and check in superheat if you have a system with a piston as the metering device. Check out "acservicetech superheat playlist" and "acservicetech subcooling playlist" thanks

[@SIX673]

great video, keep up the good work

[@acservicetechchannel]

Thanks David!

[@danielallen8560]

David Barabin

[@ramonvenegas8535]

this channel is the best thanks for you explain

[@acservicetechchannel]

Thanks Ramon!

[@munawarsoomro6207]

PS thanks for awesome videos. Enjoying your eBook as well.

[@nissangtr5296]

God bless acservtech i will always be your fan

[@acservicetechchannel]

May the Lord Bless you too! Thanks Murtaza!

[@mr.fixdaplate]

Great video

[@acservicetechchannel]

Glad you enjoyed it

[@felipeballi7679]

great vid, took these instructions with me to a job and wow everything you pointed out i tried and it worked. also did as Bernie suggested and did not leak the hi and lo pressure switches, gotta have safeties. great job, great job

[@acservicetechchannel]

Yes keep the pressure switches in series with the 24v power going to the contactor thanks!

[@rocker8692]

good explanation

[@acservicetechchannel]

Thanks Chad!

[@felipeballi7679]

great vid. great job.

[@acservicetechchannel]

Thanks Felipe!

[@geojor]

just great, thanks ...

[@acservicetechchannel]

Glad to help!

[@soloch69]

Great video like always 🙌🏻🙌🏻🙌🏻🙌🏻

[@josephcaramelli1155]

thanks a million ,

[@padilla7019]

Very helpful video

[@acservicetechchannel]

Thanks Luis!

[@damionelliott2517]

This guy is a beast at HVAC!! I ran into a situation like this before and honestly I panicked 😱 but this video definitely is informative 👌🏼only wished you had run the unit so we could see it in operation.

[@hvacguy9319]

Thanks man

[@acservicetechchannel]

You're welcome!

[@toupsclassroomtoupsclassro9557]

nice video, but for a home owner just learning some ideas will need to watch a few times ty nice clean job............so for me, I would ck the voltage going into the transformer and coming out then i guess see if power is coming off the defrost board.............?? thanks again

[@robertmunguia250]

Good video!

[@acservicetechchannel]

Thanks Robert!

[@soulme8186]

thank you for your video I have a question about the high pressure wire connected to the contact could you please explain that more

[@michaelcostello6991]

kzbin.info/www/bejne/jqLLYn6Epb98p7M

[@danielogg5446]

thanks for all the great info. mine just runs and runs. the air is never cold in the summer and never warm in the winter. its a 10 yr old 5 ton heat pump. what should the temp be coming out of the register?

[@craigkachadorian3664]

Outstanding

[@acservicetechchannel]

Thanks Craig!

[@sal8575]

very thorough information! would it work the same if you attached one of the reversing valve wires with the yellow wires and the other reversing valve wire with the blue common wires?

[@acservicetechchannel]

Sure, that takes the board out of play, and then you are running cooling on most except ruud, rheem, weathermaker, thanks

[@foxmar2005]

❤thank you so much

[@5822huron]

brilliant

[@acservicetechchannel]

Thanks!

[@atomicwalnut1581]

Thank you for sharing this info! I'm not getting a change when testing resistance with T1 and Y, meter stays at 1. I'm also not getting the low voltage to my contactor. I'm not sure if it's the board or a pressure switch that's bad. Contactor tests out fine, but it will not energize to make.

[@acservicetechchannel]

You should disconnect the compressor and fan from the contactor for safety. Then put one probe on common and one probe on the 24v hot coming off the board and follow the 24v through each pressure switch and/or temp sensors until it comes back to the board, thanks

[@atomicwalnut1581]

@@acservicetechchannel Thank you! I really appreciate the info. I'll run through that tomorrow.

[@neomacchio4692]

I have the same issue. I don’t see T1 or Y anywhere on the defrost control board. I have 24v at Y, but no 24v at the contactor. I have narrowed the missing 24v down to where it connects to the Hot1 and Hot2 which is the Hot Gas Bypass switch. HGBP. The schematic does not show how the 24v should reach that point. 🤔 I’m stumped!!

[@viper22304]

Awesome video, Thanks for sharing. Could anyone please explain to me why the RED thermostat wire was not used? Is it because the 24v is coming from the thermostat, energizing the COMMON wire from the thermostat.

[@stevehayton746]

Could you please explain about 6:39 minutes into video you took hot wire off of contactor, which you said went down to a pressure switch. You also said had to go thru pressure switch in order to have power come into fan relay. I am a bit confused here since I cant see diagram for unit. What pressure switch are you talking about and how does this effect power coming to relay?

[@neomacchio4692]

I performed this and my AC works!! TY! However, my external unit FAN doesn’t ever turn off, even when I turn off “cool” on the thermostat. Did I wire the fan wrong?

[@aicilopon26]

Would it be good to connect your pressure switch in series with your contactor in case that the pressure drops it would stop the contactor?

[@wannis100]

HiFirst of all, I want to say you work is greatly appreciated. I have been listening to your videos all the time and I have learned a lot. I want to ask you a question on Mitsubishi City Multi VRF system. I was at one site location where company had install multiple City Multi VRF system with multiple BC controllers. At one particular room with three ceiling cassettes one thermostat during hot day when thermostat demand cooling, warm air blowing from cassettes. Apparently the company who installed it was not able to troubleshoot and some other technicians where not able to troubleshoot also. Do you have any idea what is happening? Or what would be the cause of this. Thank you.

[@actarusfleed6607]

The VRF is a garbage system. Every fitting and length of copper tubing has to be engineered right on the nose plus the fact that there are no isolating refrigeration valves make it worse as God forbid should you have a leak, the whole system charge will have to be recovered. You cannot isolate any section. What a shame. Sure there's no need for ductwork however, I prefer the KISS Method. Keep It Simple and Stupid.

[@somunnavuie9167]

Thank you very help full What wire I should use if my thermostat worked with batteries and I don’t have blue or commen wire coming from thermostat ?

[@acservicetechchannel]

You would still have a c coming from the indoor unit even if from your indoor unit to your tstat you don't have a common, thanks

[@somunnavuie9167]

acservicetech thanks

[@neomacchio4692]

What is T1 and Y that you pulled and tested? I don’t have those in my Frigidaire unit ET4BE.

[@sixtower]

can you bypass pressure switches to check by jumping T1 and Y

[@WayneKellen]

Great video. I've been trying to troubleshoot a system. Basically it heated great, but once switched to cool it short cycled. I thought the defrost board wasn't controlling something right. I connected the Y from thermostat to Low Pressure switch. From there I connected the reversing valve and contactor wires. Then common to contactor and reversing valve. I also moved the fan to the contactor. The contactor jumped crazy when I turned it on. I took the low pressure valve out of the loop and it ran without stopping. I checked pressures and got a constant 75 psig and 240 psig. Looks like the low pressure was doing its job. However, checking continuity on it, it switches at about 150 psig. Is that correct? I can't find a spec on that switch for a 410a system.

[@NeGBusa]

Are you getting power from the batteries from the thermostat to turn on the condenser

[@yewannahtay8949]

Pls explain with single line dwg so that we can understand easily.

[@munawarsoomro6207]

What if I have gas furnace and not dual fuel thermostat. Can I disable defrost like you show here and wire heat W to furance W. Or even not connect O in thermostat at all?

[@jdr5501]

The condenser fan motor relay on the defrost board is normally closed. It only opens on a call for defrost; therefore, there is no need to remove wires for condenser motor in this case. The 24 volts to board has no role in keeping motor relay closed.

[@acservicetechchannel]

This is true but as a precaution if the board is bad, I would go ahead and just take the board out of play if it is intermittently working or bad and this is the first time at this job site. I would only be doing this for a short while until I get the board to be sure and while it is in ac mode. Thank you very much for your comment!

[@edmeizter8921]

jdr5501 Qq

[@eman3208]

Hi service tech,Im trying to troubleshoot a Rheem and everything operates well in cool mode, but when i turn heat mode on the reversing valve energize but i dont get the 24 volts from yout and cc to energize the contactor and after a few minutes fan and heat strips come on and it keeps operating that way... any tips what should i be looking for? thanks in advance for your response.

[@aaronclark1599]

If I'm replacing a transformer in a carrier package unit that is missing, and is missing the wiring diagram, where would I hook the low voltage wires? The red goes to the R on the board, but what about the common wire? Does it go to common on the Board, or to the contacts? Thanks.

[@ramongalaz6263]

I Have a York 5 ton package unit heat pump.Changed a bad circuit board.But know i get heat when thermostat is on cool and cool doesn't turn on.Maybe swapped wire or bad thermostat?Thank you.

maaaannn, its 2024 jan. and i am so happy i found this video. Thank you. I have a Rheem unit that is giving me hell. I can not figure out why i am NOT GETTING any heat. The unit in the heat mode gives no heat at all. The out door unit does not come on at all, (in heat or cool modes). My indoor fan run continually, but no heat. In emergency mode not heat also. The fan just keep running. The out door unit pc board is flashing on the top LED, but the bottom LED, is OFF. Dont know what that means. i am hoping that i can get some help from you sir, or anyone else, i am in orlando. It is cold now. I have no heat, i am old and cold, what a life!!!.i am not a ac man, but has gathered some good knowledge thru the yrs. The indoor unit seem to ok, it blows air out, not heated air. What can i checked? I need help. Please anyone. thnx again for this video. which it was a rheem still.

[@musclemoney4479]

I love your videos. Im subscribed. I had one question. Do you have to bypass the defrost board for Air conditioning everytime on those models if the defrost board goes bad? Even if it were cooling season and the tstat was set for cooling. Im trying to understand,i almost got it. I just dont understand why they would route the defrost board in cooling mode. Any input would be appreciated , thanks, keep up the great work.

[@MaMa-qh4dy]

In order for cooling to work on a heat pump, a properly functioning defrost control board is required. If the board is bad and you want to know how to bypass the bad board so that you have cooling, just do as Craig showed in the video.

[@papoloco34]

can you please do a full PM video in a heat pump unid...Thanks

[@acservicetechchannel]

Thank you for letting me know what you would like to see in new videos!

[@drummerdem50]

Great idea,would also like to see that.

[@hvaclifeatx7012]

Those that same concept works a American standard board?? Good video 👍🏻

[@mikeyangel1067]

What is the model of the HeatPump you are working on? Tnx

[@papoloco34]

can you please do a video in condensing unid and air handler installation and a video in how to read schematic diagrams...thank you

[@acservicetechchannel]

I do plan on making a reading of diagrams video, thanks! Check out the brazing with nitrogen playlist on the channel site. There I have a three part video of coil and outdoor unit install. Thanks

[@papoloco34]

I did already I've been watching your videos for the past two days all day long...and I still have like 100 more to watch...thank you and keep posting good videos.

[@acservicetechchannel]

Thanks Pedro and every one of your comments are appreciated. They also help the videos be found by others because of comment ranking on youtube so if you do enjoy them please keep up the comments even if they are a few words or thoughts on the subject. I also like to hear what you all would like to see coming up in the future as well! Thank you!

[@julito1959]

Pedro Rodriguez porque se congela el condensador en heat pump

[@toddiamhvact7386]

yes you could use emergency heat. You could also use heat pump for heat. Just have one contactor for the compressor and add one for the OFM making two motor controllers. Wire DFT in series with the contractors. When the DFT senses a low coil temperature it will essentially initiate defrost by cutting out the OFM. Of course this would only be a temporary fix because you would only be initiating and terminating defrost by temperature only but you would still be able to use heat pump for heat. Without the defrost board you would not be able to initiate defrost by time.

[@acservicetechchannel]

Todd, your thinking in the right direction, how do I get the customer heat if there is no secondary heat. My concerns. The dft is normally open. The dft would be closing constantly since the temp on the coil would be lower than 32 any time it were 40 degrees or lower and would close because the coil is absorbing heat from the cold ambient air. Most DFTs close at 27-32 degrees. To do what you mentioned you would also need a general purpose relay. Of course, anything could be made but a timer would be needed so the unit is not running in defrost mode so much putting cold air in the house. Thank you very very much for the thoughts and ideas! I do agree, just move to emergency heat temporarily. Thanks

[@toddiamhvact7386]

acservicetech Most DFT switches I have come across are NC but I know some are NO but like you said it depends on the manufacturer and what your unit schematic says.

[@acservicetechchannel]

Thanks for your comments Todd!

[@aircooledtx]

Why not take rv to contactor, then only have Y -common to make up??

[@acservicetechchannel]

I didn't want to confuse those who are working on ruud rheem and weathermaker as they will not be powered in cooling mode but for the other manufacturers you are absolutely right! Thanks

[@gmac280]

I just had to replace an outdoor condensing fan and the defrost board had to be bypassed in order to run the unit in ac mode. I just jumped out the fan relay and tied the outdoor fan right into the contactor and it ran fine and now it just shut off according to the homeowner. It"s a Payne unit. I'm guessing I have to power the reversing valve as well as you just did in the video. If so why did it run fine at first.

[@acservicetechchannel]

The reversing valve would need 24v on it if it is a Payne for cooling, thanks!

[@matthewszikney9574]

Let's say I bought a new defrost board and I'm reversing the bypass. Does it matter which two orange wires coming from the reversing valve go to C and O on the deforst board?

[@sixtowerhvac9133]

Will this work to use a heat pump as a straight cool unit

[@bass3man2u34]

Can a heat pump system have both type of valve on one system. piston at condenser and TXV at blower? Thanks!

[@acservicetechchannel]

Yes that is correct, thanks and I just sent you a link to a video to discuss that

[@aicilopon26]

And my defrost board is bad but I can find the oem one, could I use a board from another manufacturer that has the same functionality just different locations for the components?

[@babak921]

I have 3 low voltage wires for heat pumps and want to ADDING 1 more wire what should I do ??? I can’t change the wire

[@simonac688.]

your-realy-patient...grae-vid...thanks

[@acservicetechchannel]

Thank you Bobby, glad you enjoyed the video!

[@terrym4616]

Looking at installing a heat pump and air handler with electric strip heating for back up. I am replacing a 15KW (no heat pump) strip heater air handler. Can I downsize to a 10KW heating strip as when needed it is only adding to the heat provided by the heat pump?

[@acservicetechchannel]

The heat pump won't be supplying heat at lower temps and since you already have the correct electrical supply, you may want to stay with the 15kw but basically a heat loss calculation on the building would determine your heating needs during winter, thanks

[@phototec]

I have a Lennox HP that has burned up 3 reversing valve coils in the last 3 months in cooling mode, the unit works and cools well until the coils short out and cause the 24v circuit to blow a fuse. Any idea of what the cause could be? Any chance the defrost board is bad and would that cause the r-valve coil to short out? Thanks for any guidance.

[@acservicetechchannel]

Usually the power for the reversing valve is not stopped at the defrost board but flows through it. Normally when coils burn up it is because they are either powered on all the time or are not pulling on a load such as they may not be the direct replacement from the manufacturer that would fit well on the reversing valve cylinder. Thanks

[@jeffwilson6088]

How do you run the wires for the high / low pressure switch after bypassing the defrost board ? Any help will be greatly appreciated. Thanx

[@builder229]

They should be in series with y. So that when one of those switches open it kills the call for cooling on the contractor

[@BillyN31]

Do you need to power the reversing valve it the board failed in cooling?

[@dckid571]

Can you help me understand im new to this trade but i have two questions... Is t1 common? And is t1 and y wired in series thats why you can check for resistance? Sorry if theyre dumb questions its just bugging me

[@acservicetechchannel]

Y goes through the safety sensors and then powers T1 on the board which initiated the timer. The sensors are just breaking the hot for safety and is not a common. With the power off you could check for resistance if the wires were disconnected off the board. The high pressure and high temp sensors wouldn't trip though unless the system was on and had a problem. Thanks

[@dckid571]

+acservicetech thank you so much! You truly are the best when it comes to explaining and your videos are helping me understand hvac faster than any of my previous trade school teachers. God bless and thank you again

[@acservicetechchannel]

Thats awesome to hear man! I just got done teaching my high school students and now my Adult night school students for the night. Figured I would check in on you all. May the Lord Bless you too!

[@TheStab7]

So what do you check for onRudd ?

[@catdaddy7582]

After checking all inputs and outputs, and bypassing the board, I am real sure the board is bad at my ex's house. all 24 volt inputs are good, switch circuit has continuity, temp sensor at 5kohms. Unit has been bypassed and operating normally for several hours. Here's the rub- it's a Diamond Air model d1336hcb I installed myself 7 years ago. (I believe the electrical storm got it- we had one the night it quit- got the thermostat, too.) The board at Budget HVAC is 225- that's godawful high for a defrost board. ONLY source I've found to date. Can I not use a cheap Goodman board or something else with the basic connections? and does it HAVE to be from a unit that reverses on heat (this one does), if I wire it to operate correctly? Got any suggestions? I have another quadplex besides this house with 6 units- I need your book! \

[@aaronshoyt]

Question. I have power going into my board, but no led lights are on and no power coming out to my contacts. Thats a bad board right? But why is there no led lights showing i have power when i do? Thanks

[@bernieclement3373]

Why leave the High pressure switch and LOC switch plugged into a dead defrost board. They should be in series with the yellow compressor 24v coil regardless how temporary this is.

[@acservicetechchannel]

Ha, I'm glad you caught that. I mean't to do that in the video and I see I did not. I will put a note in the video during that section. Thank's alot Bernie. It's been a long week. Teaching HVACR daytime, night time, as well as night service calls, and weekend installs! Thanks

[@edselectricwired]

electric furnace wired

[@davepedersen6984]

Doesn't look like this unit has an outdoor thermostat. Would an ODT have any effect on strictly cooling? Or would it change this bypass method?

[@acservicetechchannel]

The odt sensor would just affect it for heating mode, not cooling mode, thanks!

[@aaronclark1599]

What if I don't have 24 volts on my thermostat wire from common to Yellow?

[@corywade4702]

Would a trane defrost board cause the Compressor not to kick on while the fans running I keep hearing a clicking already tested the capacitor ~

[@acservicetechchannel]

Usually the defrost board is needed in order for the compressor and fan to both turn on by powering the contactor. Then the defrost board relay just controls if the fan is on, thanks

[@jeffwilson6088]

What if your not getting omws from T1 to common ?

[@douglaskahane141]

I would have wired the high and low pressure switches in series with contactor

[@acservicetechchannel]

Yeah youtube took the annotation notes out on Dec 13th that had to do with that, thanks!

[@sandhusonu1067]

hey i installed two payne heatpumps both stopped working at same time the board is ok contractor power up and outdoor fan works compressor doent start at all even if i manually push contactor then also i have checked for grounded compressor and ohm resistance everthing is fine still it didnt work if i start manually it runs for 5 seconds thats all and if i tale red hot wire out it still runs the fan

[@acservicetechchannel]

Do you have power going to the compressor? For instance, sometimes there is a substance of ants or cobwebs on the actual contacts of the contactor. Is the capacitor good? Do you here a humm like the compressor is trying to turn on?

[@pascualangulo1]

👍

[@mgoblueguy]

Do you have any videos about controlling my lp gas furnace blower only while using my outdoor wood boiler, while maintaining the ability to allow the gas furnace to operate normally in case of low water temperature? I want to be able to feel comfortable knowing my house won’t be cold if I go away for a weekend without having to adjust bunch of things.

[@acservicetechchannel]

I don't have any videos on that but when I have installed them in the past, I put an additional thermostat in for the wood boiler heat circulator relay and another relay in the boiler to turn the circulator on or in a furnace to turn the blower on. Then the homeowner would simply put the boiler thermostat 10 or 15 degrees lower than the wood boiler thermostat, thanks

[@mgoblueguy]

AC Service Tech LLC , I have lp gas forced air though. If I had an indoor boiler this problem would be easy for me. What I can’t get figured out is this, with the two stat setup as provided with the Central Boiler manual, it would allow the gas to back up my OWB but my furnace blower would run constantly so long as the boiler stat was calling for heat, which it would be. I could pull 120v from the fused side of the furnace circuit for a line voltage stat with the switched side going to a low temp cutoff in my OWB supply and then to a parallel tap on the board for the blower. I’m confident this would achieve the end result I want, however, I really don’t want a second stat, and I haven’t found an economical option for that low temp cutoff. I would be happier with a 2-stage t-stat IF it would work for me. I’m just not able to verify whether that would work. Other than the defrost portion of a 2-stage stat, it seems that in heat pump stage all that happens is the blower is on or off when 1st stage is calling for heat. If it doesn’t keep up, the 2nd stage kicks in allowing the furnace to operate as it normally would, but I’m not confident that the fan wouldn’t still run constantly as with the two 24v stat setup. In a nutshell, I want a worry free automatic system that takes no special measures on my part and something my wife can not have to bother with.

[@mgoblueguy]

Can you confirm whether the 2-stage thermostat would work for me or not?

[@acservicetechchannel]

I wired about ten outdoor boilers to do what you are looking to do and always used a separate 24v transformer along with a second thermostat. You can't have two separate 24v transformers in a thermostat that are both for heat, thanks

[@mgoblueguy]

AC Service Tech LLC , Thanks for the confirmation. Was there any need for a low temperature cutout to prevent the blower from running or not?

[@woodenboatclassroom7172]

I have a 3 ton Freirich ductlass with three indoor units one is 18 thousand btu and two 9. Problem is the two 9

[@acservicetechchannel]

Is it a communication problem with those two units or refrigerant leaks?