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airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8165
Experience:  Furnace, A/C and heat pump specialist.
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I have a unit which is not running the heat pump and fan.

Customer Question

I have a unit which is not running the heat pump and fan. When resistive heat is enabled the blower comes on and resistive heat is powered up. How do I find out whether the power signal is sent to the heat pump?
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: Filter is clear. Thermostat is set to 78 heat. House is at 65.
JA: Do you plan on doing the work yourself?
Customer: yes
JA: Anything else we should know to help you best?
Customer: I just got the front panel in front of the fan off. Circuit breakers all appear to be good. the house does have alluminum wires.
Submitted: 9 months ago.
Category: HVAC
Customer: replied 9 months ago.
I am looking for a wiring diagram and schematic for the controller to the rheem rhll-hm4821ja
Expert:  airheatman replied 9 months ago.

1. Tell me what thermostat you have (Model will be inside front cover)

2. Does AC work?

3.Do you have a volt meter for troubleshooting

Expert:  airheatman replied 9 months ago.

On call for heat we should get 24 volts between Y and C as well as between B and C on call for heat at the thermostat.

Customer: replied 9 months ago.
The two schematics are insufficient to diagnose the problem. There is some intermittent command or connection between the thermostat and the final outdoor unit. I was hoping to get a schematic of the electronics in both the airhandler and the garage so I can track down whether an electronic relay has gone bad in the circuit path. I am an electrical engineer and can find my way around the schematic. The schematics provided are simpy wiring diagrams of how several wires connect between the thermostat, the air distribution system and the outdoor heat pump.
Expert:  airheatman replied 9 months ago.

The diagrams sent are strictly the wiring for what controls the heat pump at from the controller (Thermostat)/ If you would like schematics of the units themselves I will be happy to upload them for you.I will need model on outdoor

Expert:  airheatman replied 9 months ago.

Here is the one for the air handler showing where thermostat wires connect from thermostat.Please provide model on outdoor and I will upload wiring diagram for it.

Expert:  airheatman replied 9 months ago.

If outdoor is also Rheem it will be like this.

Red to R at thermostat and R outdoor

Brown to C at thermostat and C outdoor

Green to G at thermostat

All whites to W/W2 at thermostat and D outdoor

Yellow to Y at thermostat and Y outdoor

Blue to O/B at thermostat and B outdoor

Let me of any other questions.I am here to help y resolve this.

I will need model on outdoor to provide a schematic on that unit

Customer: replied 9 months ago.
The heat pump started after I reinstalled the cover over the electronics control unit last Sunday. When the cover was off, I lifted the lid to the electronics controller in the heat pump and it indicated that it was in stand by state (0).It worked, from what I am told by my sister who owns the house, that it stopped working sometime later in the evening. Based on what little information I know, the problem would appear to be the result of either an interlock safeing or ???. Possibly a thermostat problem or a broken wire between the thermostat and the heat pump. Based on the fact that it started briefly, I think it is an intermittent wire or interlock.
Expert:  airheatman replied 9 months ago.

One thing you may want to check is to see if maybe there is a float switch wired into the main condensate drain.It may be partially blocked and as water seeps out allowing it to close and let unit run until it backs up again. We can go from here.

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