[jaystone10]

Need some help please, I have moved into a house that is about 10-year-old. The A/C seemed to work fine but I have tried the heat and it’s not working right. Here what it’s doing. When I turn the thermostat to 72 the heat pump will turn on outside. I go upstairs and removed to furnace cover and can feel the heat off the coils. But after maybe 10 minutes the outside unit turns off and the aux turns on. Now when the thermostats get to the set temp the heat turns off but the blower fan won't. I can get the fan to stop blowing by turning the temp down by 1 degree. I have two units and both act the same. Anyone have an idea what to check also both Thermostat have the check light flashing.

E1RE036S06G
E1RE042S06G
F2RP036H06G
F2RP042H06G
Robertshaw thermostat 9620
Robertshaw thermostat 9620

 

[Bitters]

Sounds like it's going into defrost mode.

 

[jaystone10]

It not the defrost mode. I can manually set the defrost on one unit but not the other by shorting the test pins on the defrost board plus the either unit builds up ice.

 

[beenthere]

Are both units doing this, or only 1.

Could be defrost. But sounds a bit more like a safety is shutting down the outdoor unit.

 

[jaystone10]

Both.

 

[beenthere]

May be a thermostat issue.

Next time it happens. Turn the breaker to the air handler off. Wait a few seconds, turn it back on. See if heat pump starts again in 5 minutes.

 

[jaystone10]

I've removed the brown and red wire from the thermostat and jumped them together and the heat pump turned on but shut off after some time. Found this on the defrost board.

 

[sktn77a]

There appears to be some burning under those 4 blue resistors but that doesn't necessarily mean anything is wrong (resistors do get hot).

 

[Technow]

I've removed the brown and red wire from the thermostat and jumped them together and the heat pump turned on but shut off after some time. Found this on the defrost board.

When you jumped the heatpump at the thermostat, did you also turn the indoor fan on?

 

[HVACDave]

Does it always move to aux after 10 mins every time? I would suspect there might be something in the thermostat set up if that is the case. eg.. it will run on heat pump for 10 mins and if demand isn't satisfied it will energize aux heat till cycle complete.

 

[HVACDave]

The thermostat manual indicated that the differential was adjustable for both first and second stage heating. Do you know what that differential is set at?

 

[jaystone10]

I set the differential to 2 degree on both units default is 1. Heat turned on today I went outside and both units were off. I turned both breakers outside off then back on and waited 5-6 minutes and neither turned back on.

 

[beenthere]

Should have turned the breakers to the inside units off, and then back on. Not the outside unit breakers.