Intertherm Heat pump issue? need help!! model T3Q

Questions about repairs and parts for Nordyne furnaces, air conditioners and heat pumps for manufactured homes including Intertherm, Mac and Miller brands. Click here for Nordyne parts.

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Willc
Posts: 65
Joined: Sat Apr 14, 2007 6:29 pm
Location: Albemarle NC

Mon Mar 09, 2009 7:13 pm

I came home and my thermostat was flashing no ac power and found I had a blown transformer. I have a 220 air handler with strip heat. I have tested the heat pump by pushing in the contactor test button it comes on. I replaced the transformer and the t stat still said no AC power after a long time I hit the reset button on the t stat :oops: and reprogrammed it. When the heat pump tries to come on it shut down everything and goes back to flashing no AC power!!! I was luck it did not take out the transformer again. The heat pump has a new start capictor and the cont actor has little pitting.

Am I looking at a bad board?

The airhandler seems to work fine
Starting over remodel junkie


tritontr
Posts: 58
Joined: Thu Dec 18, 2008 11:56 am
Location: Alabama

Tue Mar 10, 2009 4:22 pm

Have you just installed the programable t-stat or has it been installed for awhile and everything has been working fine in the heat/cool and emergency heat mode? The reason I ask is that it sounds like you have a short somewhere in your 24v side of the system. If you just installed the stat you have to make sure that your C (common) wire that attaches to your t-stat,Air handler,and then goes to the outside unit does not mistakenly get connected to the other side of the 24v circuit. Look at your wiring (not just the color) and make sure that the wire on C terminal of your t-stat is the same wire on the C terminal of your air handler and goes to the C terminal on the outside unit and you have only this wire on your C terminals.. The wire I am referring to is the field installed low voltage wire. If the wiring looks ok check where it enters the airhandler and outside unit and see if some insulation has been worn away that causes the other wires not the C (common) wire to touch metal.

a123

Tue Mar 10, 2009 5:48 pm

this is Willc havving log in issues
the t stat is the same one that has been on the unit

tritontr
Posts: 58
Joined: Thu Dec 18, 2008 11:56 am
Location: Alabama

Wed Mar 11, 2009 8:31 am

If your wiring looks ok and your air-handler runs fine in the fan only and emergency heat mode and you have never had to reset a breaker then heres where it gets tricky. You would have to have a meter a set of jumpers,and a lot of knowledge on the wiring diagram to pinpoint the problem. The possibilities are a bad contactor coil, defrost board, reversing valve solenoid(if 24V) or any other device in the LV-24V circuit. Some of these devices have both high and low voltage going to them so where you put your meter probes and hands can be dangerous. I would call out a tech because some of the items you can just disconnect the wires and test but a tech would install a fuse link in the system while he was testing to keep from shorting out another transformer. Also it can get quite expensive by parts changing without a clear indication that the part is bad. This is where the services of a licensed tech would save you money.

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