Trane xe1000 and Honeywell RTH 7600


  #1  
Old 04-17-14, 10:26 AM
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Trane xe1000 and Honeywell RTH 7600

Hi everyone, great place here. A little background on me and the issue I have. I am retired Navy A-Ganger. I've worked on refrigeration systems, mostly R-12 tho. I own a marine engine repair business and I work on and understand electrical and do a lot of DIY projects.

Ok, I had a AC guy come check my unit out. I told him that when the unit goes into defrost mode, cold air blows, cooling the house down, then of course the heatpump has to run again now to heat the house up. He said the air handler didn't have a jumper installed to turn on aux heat during defrost (which he said all heat pumps are suppose to be wired to do this). So he did whatever he did and left. When I notice the unit in defrost mode, seems it's blowing cold air again.

After he repaired (whatever he did) I had to change thermostats from a Honeywell RTH6350 to a Honeywell RTH7600. Honeywell said the first tstat might be bad. The first tsat would run the unit a long time even after the tstat showed the house was 70, which is where it was set to. It would basically run and run and turn off whenever it decided to.

What I would like help with is reading this wiring diagram to see how the unit turns on the aux heat when it goes into defrost being controlled by the Honeywell tstat?
Specifics would be great and I can understand the technical info given. I assume the coil bottom sensor (CBS) is what turns the unit on/off to defrost but I can't really see how it does it? Or if that is incorrect please explain.

My tstat wiring is as follows:
unit - 7600 tstat
R - RC -jumped to R
W - E-jumped to Aux
Y - Y
G - G
O - O/B
C - not used
T - not used

diagram split because it was too small to read
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Also here is a pic of my original tstat.
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  #2  
Old 04-17-14, 11:46 AM
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Hey boat, CBS detects 28* and closes, starting the timer in DFC. If it is still below 28* after 30 mins. it goes in defrost mode. Relay opens, stopping fan and energizing X2, which starts the heaters.
 
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Old 04-17-14, 12:24 PM
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Thanks for the info!!
So this should be right; W from the tstat is jumpered to X2 in the air handler/heater. This energizes the heater in defrost mode as you pointed out, and also, when the tstat is switched to emer heat.

So as long as X2 and W are connected all should be good. AND also, the black wire from the DFC should be connected to X2 from the X2 connection on the DFC.

And this is strange. I was with the guy when he removed the cover from the outdoor unit, and a black wire was there he said wasn't used. I believe that was the black wire from the DFC going to X2.

My original tstat had W jumped to X2, and there was a black wire connected to that X2. He removed the black wire from the tstat and said it wasn't used?
Now I'm wondering if he screwed it all up. I'll have to go look at the wiring outside and in the air handler.

Thanks again
 
 

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