Heat Pump Defrost Board Troubleshooting Tips

[@foxfamilyhvac]

This video focuses on the defrost cycle of a heat pump. It's function is to control the sequence of events to melt the ice off the coils of the outdoor unit when the system is in heating mode. I hope you like the video and can take something from it.

[@al1383]

I've had a ton of brand new defrost boards malfunction this season! Last one is 3 weeks out. Others must also be having to replace trane defrost boards. Bad part is when it goes bad it goes into defrost over and over. Every 5 minutes or so. Which causes high power bills. I like being a trane dealer, but this sucks ass!!!

[@saulsanchez9531]

where can i find that book ? i already looked on amazon and your page

[@alfonsobenitez8574]

Excellent explanation. No doubts you are a professional, i am a retired HVAC bussiness owner, 68 YO, i enjoyed very much watching your videos. Been doing A/C for over 16 years, and i sure can tell you that we never stop learning. Is important to be humble, i know of people in the business that think they know it all and end up making mistake, i take pictures of boards, and whatever is necessary to make my job easier. Thank you for the video. You always get thumbs up with me.

[@GotchaplumberGotchahvac]

Thank you ... always need a refresher from time-to-time.

[@miguelhernandez155]

That you so much you video resolved my heat pump problem it has ice built on the out side of the coil i removed carefully and now my heat pump is give me good Heat Miguel 12/25/21 Connecticut..

[@DayClanTribe]

Nice detailed informative video. I found this while searching how to do a manual defrost override. Nowhere did it mention this so I'll go ahead and state it there has to be a call for heat in order to start the manual defrost cycle.

[@dillonlexington]

Thank you for these educational/informative videos!

[@foxfamilyhvac]

For sure man. Thanks for watching

[@jesusdelgado2232]

Awesome video, I NEEDED this refresher.

[@foxfamilyhvac]

Awesome

[@SEANRMZ]

Thanks for tips, mine is frosting up. Now if I can put mine into cooling mode with cold air flowing from the inside, the reversing valve should be fine?

[@functionalvanconversion4284]

Awesome information! Trying to learn how these complex machines work 😊

[@TheWilferch]

Excellent tutorial valuable for saving... !!!! .......

[@foxfamilyhvac]

Thanks!

[@TheWilferch]

@@foxfamilyhvac ... easy for us viewers to say when seeing such excellence in presentation.....cheers !

[@renecuevas4128]

Wow the explanation was right on the money. Tnks

[@foxfamilyhvac]

Sweet!

[@hvaclifeatx7012]

Hey bud great video,,, question have you ever done a video on how to bypass defrost board for cooling??

[@foxfamilyhvac]

I will work on that for you. Thanks for the idea.

[@InsideOfMyOwnMind]

I'd always prefer someone who is open and straight forward about how things work servicing my unit. I'm really quite sure you're going to get a call from me when the time comes, most likely on a 118F day lol. That seems to be how it works.

[@foxfamilyhvac]

Lol. We'll get you taken care of for sure! Thanks 👍🏻

[@nakiapringley5391]

Great video brother 💯💯💯💯

[@DayClanTribe]

To initiate the defrost cycle I had to first unplug the hot pink lead which was the outdoor temperature sensor I believe and put a jumper on it. Then I had to Short the terminals called speed up which advanced the defrost cycle. You then remove the jumper on the "speed up" terminals once it starts and let it run. However my problem is that it goes back into normal heating mode only a few minutes later long before the ice has melted.

[@mjfollrd]

If the dft is continually closed in the summer will unit go into defrost and activate indoor auxiliary heat

[@rcinfla9017]

I think the primary reason for reversing valve defaulting to heat mode unenergized is to exercise the valve during the summer so it less likely to get stuck from just sitting in one place. It moves over fairly quickly so there is not likely much internal coil heating when cooling first comes on as it takes longer for refrigerant pressures to build up to full pressure in system. I believe the reversing solenoid just opens a capillary tube port to enable refrigerant pressure to do the real work to move the reversing valve.

[@officerkrupke4966]

Yes, a bad dft sensor that is stuck closed will shut down outdoor fan and turn on strip heater for ten minutes, probably causing high pressure switch, if installed, to shut down unit until pressure switch resets, than will cool for thirty minutes, go back into defrost and repeat, unless unit is equipped with a monitor that wont restart unit until fault is corrected. If you feel heat coming out vents, go to outdoor unit and check to see if you are in defrost mode by seeing if fan is off and testing to see if you have 24 volts on W2.

[@d.redenius5639]

Most heat pumps energize the reversing valve coil in cooling via the orange wire or "O" terminal. However, not all manufacturers energize the reversing valve in cooling. Rheem for example energizes the reversing valve in heating mode or with the "B" terminal. In that case some contractors use the blue wire for the reversing valve.

[@foxfamilyhvac]

Exactly. Yeah thsts why I try to say something like 90% of units or most units work this way. But yes you are right about Rheem /Ruud. Any others that you know of?

[@jkbrown5496]

There's plenty of heat content in the air below 40F. US manufacturers were slow to design for lower temperatures but it's neither a thermodynamic or technology limit. There are mini splits for operating down to -22F (Hyper Heat). Adaptive Demand Defrost was designed to reduce defrost cycles when the outside air is cold and dry via the ambient and coil temp comparison instead of relying on the defrost thermostat and run time after the DFT closed which took no account of the humidity in the outside air. Below 40F, you do lose efficiency from the 250-300% normally as the defrost cycles at 100% eff for electric heat add up. And while manufacturers are wising up, heat pumps only supplied 90F or so at the vent which "feels" cold blowing from a vent. I understand some have upped the supply temps.

[@foxfamilyhvac]

That's great information JK. It sounds like you have the experience to have seen the temps get really low outside and still have the heat pump work well enough to heat the building. Thanks for letting us know!

[@danielgarbuzov8106]

My heat pump goes into defrost mode at night, but it takes about 10 or 15 min to get warm air blowing again out of the ducts, is that normal or are the auxiliary heating coils suppose to heat the air immediately? It's not that cold here, rite at freezing, but when the defrost mode kicks in the house cools down quite a bit, up from 72 down to 68, and it's like that all night.

[@tserevenad]

I am getting 24v at the reversing valve, yet the 220 breaker pulled and the honeywell 5000 is set to system off. I can't get the compressor to run.

[@Ray-wr2wr]

meaning on the heat pump no need for Y wire ? only orange O terminal

[@foxfamilyhvac]

Thanks for watching. Hope this video helps you in the classroom and out in the field!

[@countryside8122]

Mine froze up a couple times in a snowstorm. However the unit automatically defrosted itself. It does take a little while.

[@timrowe234]

Good video! Thanks

[@sincityhvacr]

thank you greg great video

[@foxfamilyhvac]

Thanks Vegas!

[@paulgugger8987]

Heat pump blowing cold air. I reset it by putting it on AC and switching breaker off and on several times. when I switched back to heat it works for a while and starts blowing cold air again.

[@stephensmith3184]

What if heat pump reached call,condenser kicked off as normal and air handler and heat strip stay running continuously?

[@stephensmith3184]

Already replaced sequencer and need advice! 🙏Please advice!

[@The1realro]

Any answers brother ?

[@wildcardab]

We have a 3-stage heating system, heat pump + propane. I'm hearing what sounds like the defrost cycle kicking in and running for an hour+ on days where the heat pump never kicks on because it's too cold out. Sounds like from your video the defrost cycle shouldn't kick on when the heat pump hasn't run. What could be causing this? How could I troubleshoot?

[@caru3257]

heat pump + propane is two stage unless you have a heat strip. heat strip not a great idea. it should not run defrost if the heat pump has not run.

[@jemilsense3972]

how to quiet a TXV DURING DEFROST sounds like air brakes. Is there a way to quiet it or wire it so the heat scripts come on instead of that air brake sound?

[@foxfamilyhvac]

No, sorry. It's a necessary function. No way around the noise except relocating your Outdoor unit to a spot better tolerated.

[@petesingh292]

How would you charge Freon in winter months?

[@foxfamilyhvac]

A whole other video Pete. But this is a great blog about it. Thanks 👍🏻 www.hvac.com/blog/how-to-charge-a-heat-pump-in-the-winter/#:~:text=Because%20the%20outdoor%20coil%20operates,down%20to%2020%C2%B0F.

[@d.redenius5639]

What I do is first determine what type of metering device is being used. I will then energize the unit in cooling mode. I will take a plastic warp and wrap the condenser to raise the head pressure to simulate a higher ambient temperature. For R22 I will raise the head pressure to 225 psi. For 410a I will raise the head pressure to 375 psi to simulate a 95F ambient temperature. I will never cover the fan shroud, only the coils. Once my head pressure stabilizes to that pressure, I will then measure my superheat or subcooling to determine if I'm properly charged for a 95F day. If my superheat or subcooling doesn't match, I will then know I'm not charged properly. You can also follow the manufacturer's documentation (usually stamped on the back of the control door compartment) which will tell you what your superheat or subcooling should be in heating and cooling mode. You will need to find your ambient temperature and find it in the chart provided. Take a measurement and compare.

[@4thlinegooner582]

There is a 3rd port usually center and a little above where the other 2 are, some call it the true suction port.

[@juanaguilar2453]

Good video.

[@jhhvacplumbing1944]

Good job foxy

[@foxfamilyhvac]

Thanks bud!

[@arthurwilliams4160]

Thanks

[@NorCal-refrigeration]

We are almost to all heat pumps on new construction in CA. The power grid is going to get whacked good. Electric heat only and electric cars.

[@jkbrown5496]

Only when it's very cold or very hot and the fair weather electricity producers using wind and solar disappear from the grid.

[@foxfamilyhvac]

Yep. That is the way it's going. Gonna get get crazy for sure.

[@paulgugger8987]

Newsom is a Communist POS!

[@Mikecianfrocco]

Airflow is backwards on the tam9 diagram 🤫

[@foxfamilyhvac]

Yep. You are absolutely correct 😁 Can't believe I did that! Thanks

[@petesingh292]

How would charge Freon in winter months?

[@Greenenvelopeaire]

U dont

[@d.redenius5639]

What I do is first determine what type of metering device is being used. I will then energize the unit in cooling mode. I will take a plastic warp and wrap the condenser to raise the head pressure to simulate a higher ambient temperature. For R22 I will raise the head pressure to 225 psi. For 410a I will raise the head pressure to 375 psi to simulate a 95F ambient temperature. I will never cover the fan shroud, only the coils. Once my head pressure stabilizes to that pressure, I will then measure my superheat or subcooling to determine if I'm properly charged for a 95F day. If my superheat or subcooling doesn't match, I will then know I'm not charged properly. You can also follow the manufacturer's documentation (usually stamped on the back of the control door compartment) which will tell you what your superheat or subcooling should be in heating and cooling mode. You will need to find your ambient temperature and find it in the chart provided. Take a measurement and compare.

[@petesingh292]

Thanks for quick response guys

[@DayClanTribe]

Weigh it in. then recheck in summer.

[@shloomyshloms]

most defrost boards can be easily repaired for less than $50

[@doggyd96]

Very helpful