DEFROST Control Board Wire Terminal Functions! Heat Pump Defrost Cycle Explanation!

[@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 a link to the UEI DL389 Multimeter used in the videos- amzn.to/2av8s3q 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 Here is the link for the Irwin Wire Stripper/Cutter/Crimper amzn.to/2dGTj2V 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.

[@kennethmowery702]

AC Service Tech LLC can you help me someone wired my unit completely wrong [e-mail]

[@lucdumouchel3864]

Keep teaching us. I've been doing this for many years and , I just keep learning. Thanks to share your knowledge

[@acservicetechchannel]

That's great to hear!

[@charliewingard6244]

Thanks!

[@PBS-nm1uu]

this is the greatest video i have seen and i have looked at a lot of them please keep it up, just found your video thanks a lot !!!!

[@acservicedaytona386portora3]

Again I enjoyed your video, your a great teacher I love watching them all.

[@acservicetechchannel]

Thank you very much Robert!

[@juancortes2140]

Thank you for your help

[@acservicetechchannel]

Happy to help

[@aaronclark1599]

Such a great class..

[@nathanmgg]

Danm I came here to see if you knew anything about the quiet shift function? During summertime whenever my ac turns off it makes a loud trumpet sound. I was wondering if this dip switch would fix it or if that would only work for the defrost

[@rocker8692]

Good explanation

[@jimbola77]

very nicely explained! thank you for sharing partner!!!!

[@acservicetechchannel]

Glad to help!

[@ryanshepherd581]

I'm getting ready to put this very board in and have a question on the setting for 30 60 90 120 switch. How do I know which way to change them to get desired time?

[@deloct]

Great video and well explained, thanks! Can you make a video on proper way of troubleshooting defrost boards? it will be very helpful to me as all of your videos. Please keep encouraging new techs to get better out there on the field. Thank you!

[@acservicetechchannel]

Thank you very much! I will have to see what I can do. Thank you for the video idea!

[@popsmccartney435]

Great video, thank you for sharing.

[@acservicetechchannel]

Glad to help!

[@nurfetalic205]

Greg great presentation in order to troubleshoot any heat pumps especially electrical components and Boards will be great help for any service tech to have some experience in electrical background that will speed up any troubleshooting and resolving all solving electrical problem as far as the boards switches contactors and other components related to the units I am master electrician by trade I work for a big company that have at least over 100 rooftop units ranging from 5 tonnes to 150 tonnes chillers water source heat pumps heat pumps vfds all kinds of units and on occasion HVAC technicians will ask me to help them out with the electrical troubleshooting on different units but I must say heating air conditioning is very complex field

[@acservicetechchannel]

Absolutely and it is constantly evolving, thanks very much Nurfet!

[@Tractorhap]

Excellent

[@acservicetechchannel]

Thank you so much 😀

[@keithhoward8651]

Great video. Thanks for the info

[@acservicetechchannel]

Glad to help!

[@papajoe3832]

Great video and excellent to see mentioning the Ruud and Rheem RV is de-energized in Cooling mode unlike most other manufacturers. What about Weathermaker and AmeriStar that I have also heard need the RV solenoid energized for Heat mode? The way I remember the four is WARR acronym. Thanks for sharing yur time and knowledge.

[@acservicetechchannel]

I believe Ameristar reversing valves are powered in heat mode though we do not see many of those around here at all. Carrier's Weathermaker may have some really old old units that were powered in reversing mode but I believe most are powered in cooling mode. Thanks for the thought on that subject!

[@DayClanTribe]

Papa Joe, I'm curious about your reference the acronym WARR. Please define?

[@juancortes2140]

God bless you

[@mjfollrd]

If the dft is constantly closed in the summer will unit still go into defrost activating auxiliary indoor heating ?

[@Pretzel114]

AWESOME VIDEO!!!!! This helped more than you know. One question, when the W2 is energized could that also turn on a second heat source, like gas or oil or is it just for the electric strips in the pump? Thanks again this was great.

[@acservicetechchannel]

Nice question! During defrost this is the only time you would ever have a furnace turning on while a heat pump is running in a dual fuel system. You would never wire the aux from a thermostat to a furnace but yes you can wire the w2 from the heat pump to the w on the furnace. Thanks

[@Pretzel114]

acservicetech Thanks for the reply acservicetech. Your videos help fill the gap in some of my brain holes lol! have a good one.

[@acservicetechchannel]

Ha ha, nice

[@ryanshepherd581]

On the 3 switches how do i set it to defrost every 30 minutes

[@geojor]

always good, thank you ...

[@acservicetechchannel]

I appreciate it!

[@hvacrjunky6119]

Another great video!

[@acservicetechchannel]

Thank you very much!

[@larrycavanaugh7410]

Hi great video I was wondering if you could tell me why my Inverter single zone ductless mini split would go in defrost mode +7° Thank you

[@acservicetechchannel]

Heat pumps may run in defrost any time the outdoor temp is 40 degrees or less because the refrigerant in the outdoor coil is below 32 degrees F

[@MaMa-qh4dy]

Before I condemn the defrost board part number Trane CNT 02941. Split unit heat pump. Two defrost temp. sensors (ambient and coil). Defrost is auto "demand". Condenser ices-up. I short out force-defrost pins, unit enters defrost mode, OD fan cuts out, but ONLY 5VAC to reversing valve. Should be 24VAC in order to switch-over refrigerant direction. Reversing valve coil Ohm checks good. Both sets of sensor pins on defrost board show proper voltage at 5.5VDC. Both outdoor temp. sensors ohm out good relative to outdoor ambient temp. LED flashing normal. I had to melt the ice by shorting out force-defrost pins and temporarily jumpering R-O wires at condenser which sends 24VAC directly through defrost board to activate reversing valve. So, reversing valve is not automatically receiving proper voltage during defrost cycle. Any suggestions for other tests prior to condemning defrost board? Thanks.

[@MaMa-qh4dy]

I just replaced the board and all is fine. I think that I covered all of the possible tests that can be conducted in the field as described in my first message. On the solder-side of the bad board, I did notice blackening on one single solder connection indicating "burn."

[@SombraLocs]

Can you make a video on troubleshooting the main control board on a gas furnace? Is there a way to actually troubleshoot a control board? Or do you have to use process of elimination?

[@acservicetechchannel]

You nailed it. Since you know the sequence of operation of what it is supposed to do and the control board does not do it when you are applying 24v control voltage then the board is bad. There are no mainstream tests for control boards. They are to do a function when control voltage is applied. If not and you are measuring for voltage coming off of the board and it is not there then the board is bad. This is another reason why sequence of operation is so important on heat pumps, HSI furnaces, and spark ignition furnaces. Great question!

[@SombraLocs]

acservicetech Thanks!

[@Rangerscott77]

Would a bad defrost board keep the outside unit coming on at all? Inside unit working just fine. New capacitor amd contactor. Getting 230 volts from cutoff and 24v from tstat wires. Have to push in the contactor for compressor and fan to turn on. Both sound normal when they kick on.

[@MarcusHamilton-vk1tt]

You’re the best

[@sudeshputran69]

Super

[@acservicetechchannel]

Thanks

[@uruiamnot]

I was 2 minutes into the video before I saw the exploded capacitor!! Show and tell now.

[@acservicetechchannel]

I don't remember what made this board fail but just had it around so I figured I would explain with it, thanks

[@EnjoyCalculus]

What happens if the DFT closes in 30 minutes and you have the dip switches set to 90 minutes?

[@ThaVerse]

How can you tell if the low pressure switch has been actuated?

[@harrypezzi9901]

I like this

[@acservicetechchannel]

Thanks Harry!

[@jonathansanow1728]

So going off of your videos if I have 24v coming through my wire to the t1 terminal but do not have my 24v going to the contractor I have a bad board. Am I following correct.

[@acservicetechchannel]

During the call for cooling or for 1st stage heat, if you have 24v going through your safety switches back to T1 and the board never sends 24v off of t2 after a five minute delay then you may have a bad board but make sure you check your wiring diagram first to make sure that all of the wires are where they should be first. Thanks

[@jimmyung3212]

great video thanks.

[@acservicetechchannel]

Man you are really going for it and learning as much info as possible, that's great! What kind of HVACR experience do you have to date?

[@jimmyung3212]

I am just a freshman in HVACR.

[@jimmyung3212]

I mean my first year as a tech.

[@acservicetechchannel]

Well good luck, it seems that you are sucking up as much information as possible. The ones who are hungry and determined will be the valuable tech's later. Initiative is a funny thing!

[@DayClanTribe]

Thanks so much for another great video with superb insight to manufacturer's detailed internal settings. One question I have regarding a typical defrost cycle: According to my unit literature the aux heat is optional during defrost cycle and if so I imagine the indoor blower runs as part of necessary evap required and wouldn't that blast cold air indoors? ...or is the relative load so high no fan is required which I can't imagine being possible?

[@acservicetechchannel]

Yes your indoor unit would not know that you are running in defrost other than that w wire heading in from the outdoor unit. Actually the fan needs to be so that the refrigerant has heat to absorb and when elec resistance comes on, that actually provides more heat for the refrigerant to absorb and some heat to keep the temp in the house from falling, thanks Tie Dye!

[@koreymayo8884]

I thought default is usually 30 minutes defrost not 90?

[@notanewbie1718]

What if hp starts in heat mode, runs 3-4 minutes then shuts down and goes into 5 minute delay. After delay, hp starts and runs 3-4 minutes and then shuts down again on 5 minute delay. And continues to do this. A sensor wouldn't cause this problem would it? What might be the problem? Bad board or something else?

[@Multianonymous73]

Pressure switch

[@ParabellumX]

A Rude Rheem gains power when it's in heat. 🤣

[@juancortes2140]

Thank you for your help

[@acservicetechchannel]

Always welcome