Pool Heat Pump Runs but Doesn't Heat

[BikerBill]

We have an AeroTemp model 155 heat pump for our swimming pool. It's about 5 years old and doesn't get used all that much. The other day I noticed the heat pump wasn't running at all. I reset the circuit breakers which had tripped. Now the heat pump powers up (panel lights up, fan runs) but does not heat at all. The exit air temp is the exact same temp as the ambient air.

Prior to this problem the pump worked fine, so I don't think I have a slow refrigerant leak. I'm guessing the compressor isn't turning on. The indicator light that signifies the unit is heating is illuminated. So it's trying! What could blow/burn out to cause the breakers to trip and then the compressor not run again? Start relay? Start capacitor? Compressor motor itself (please say no)? A sensor of some kind?

BTW, there are no trouble codes that display on the panel.

 

[BikerBill]

More Info

OK, so I tore into the heat pump this afternoon. On the printed circuit board there is a contactor that controls the compressor. One of the compressor motor wires (red) was badly burned and separated from the screw terminal on the contactor. I was thinking of cutting the burned part of the wire off and reconnecting it to the contactor but in the process of removing the wire the screw terminal just pulled out of the body of the contactor. There was obviously a lot of heat in that area. The two capacitors looked fine.

Of course, this contactor is obsolete (on a five year old heat pump). I seem to have located a suitable equivalent. My question is: if I just replace the failed contactor will that likely fix my problem or is the burned contactor and wire just a result of another (overcurrent) problem? What could that problem be?

 

[gtemkin]

Just a guess, but I'd say it was just another example slightly "loose" connections that eventually overheated. Doesn't hurt to really go extra tight on high current screw terminals.

 

[BikerBill]

Back in Business!!

I installed the new contactor and the heat pump seems to work fine. As you suggested I cranked pretty good on the high current terminals. Thanks for your help.