No Power to the Thermostat

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  #1  
Old 11-23-15, 11:35 AM
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No Power to the Thermostat

I have a Payne Heat Pump, model ph13nr024-f. I noticed that my thermostat was blank last night and checked and there is no power coming in to the thermostat. After going through some of the basic normal troubleshooting steps I have found that I have power coming to the heat pump outside but no power coming back into the Air handler and up to the thermostat. I checked the condensation pump and it is working no blockage, fuses and breakers all good. I can not find anything on here that describes this particular issue. I have ordered a new control board (p/n HK32EA001) but I want to make sure there isn't something I can check first.
 
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Old 11-23-15, 01:11 PM
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There is a 120/24 vac transformer somewhere in the heat pump control. The t'stst operates on 24 vac. Look on the control board for a fuse for the 24 vac. It could be blown. Good luck.
 
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Old 11-24-15, 03:05 PM
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Thanks for the tip but the fuse is fine. There is power to the heat pump but no power coming from the outdoor unit back to the air handler
 
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Old 11-24-15, 03:46 PM
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There won't be any power coming from the heat pump to A/H. Check the R terminal to com in the A/H, should have 24V.

I looked at the board you ordered, that's the defrost board, won't have anything to with the stat having power.
 

Last edited by skaggsje; 11-24-15 at 03:51 PM. Reason: added info
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Old 11-27-15, 04:33 PM
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Thank you, I should have said vice versa, yeah I figured the defrost board out after the fact. I should have taken a little more time to research first but because it was holiday didn't want to be stuck without parts. I checked and the R and term and com and have 0. I guess it is just a process of elimination from here. Thank you again for the tip
 
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Old 11-27-15, 06:37 PM
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No power to Thermostat

Okay, someone should be able to help me, i'm going nuts. I am somewhat mechanically inclined but admittedly do not have a lot of experience with heat pumps. I used my multimeter and I have checked inside the air handler the limit switches, both seem to be good, the transformer 240 on one side 24 on the other, new fuse, capacitor checked out, thermostat itself works. I checked the fan and motor to make sure it would cut on and it seems fine. I do not know what i should look at. Do you think I should go ahead and just replace the relay, transformer, switches and the boards?
 
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Old 11-27-15, 06:49 PM
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Does the fan run when you jump R to G at the air handler?

If it does, try jumping R to G at the thermostat.

R - 24vac power
G - fan
Y - compressor
W - heat strip
C - 24 VAC common
O - reversing valve for cooling

Jumping R to C will pop the fuse.

G is often a grey wire at the air handler if you have pigtails.

What terminals were you measuring to prove voltage?
 
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Old 11-28-15, 05:56 AM
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If you have 24V on the output of the transformer, then you should have 24V at the thermostat. If not, check the wiring between the air handler and t-stat. Remove wire nuts and check for loose or broken splices, chewed up wire, etc.
 
 

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