Heat pump heats with aux/emer only

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Old 02-19-15, 12:21 PM
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Heat pump heats with aux/emer only

Hey all. I have a Goodman split system (Heat pump with backup electrical heat) that covers the upstairs of the house. Our last couple of electric bills have been a good $150 or more than they should be. On a whim I disconnected the aux/emer leads on the thermostat on the downstairs unit (Goodman packaged unit) with no degradation. Tuesday night I did the same and the kids woke up the next morning to 63 degree temps.

With the aux/emer disconnected, the outdoor unit and the indoor blower does not run. With the aux/emer connected, the blower comes on and the get 120+ degree
heat from the vents.

1. Could this be a wiring issue? I replaced the thermstat in August and could my wiring be messed up? See before and after pics attached. Before is an old Janitrol, the new thermostat is a Honeywell TH8320U1008.
2. Does it make sense for the blower to come on with aux/emer heat, but not if the heat pump itself was not coming on? i.e. Is there an interlock that waits for the heat pump to come on and then the blower will come on?
3. Any other suggestions or troubleshooting?

I have a service call scheduled for Tuesday, but if I could resolve it first, I would love to. Thanks for the help!
 
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Old 02-19-15, 01:26 PM
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If the heat pump doesn't start up and run and the temperature differential is more than three degrees on the thermostat..... the back up will run.

It sounds like you need to see why the heatpump isn't running.
When you installed the Honeywell stat did you program it for heat pump operation with backup heat ?
 
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Old 02-19-15, 05:04 PM
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Most of the heat pumps I see will run with the set point well above the room temp. The only time they won't is if the stat is set for emergency or if there is an outdoor stat to shut them down below a certain outdoor temperature.

There is a five minute compressor delay built into the thermostat.
 
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Old 02-19-15, 05:22 PM
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I installed the same thermostat on both systems and set them up the same. They are set as heat pump with aux heat and the o/b (reversing valve) was set to energize to cool.
 
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Old 02-19-15, 05:38 PM
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With the aux/emer connected, the blower comes on and the get 120+ degree
heat from the vents.
Does the fan on top of the unit ever come on?

Swap the two stats. If the problem follows the stat, you have a bad stat.
 
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Old 02-20-15, 08:18 AM
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Good call Grady, I will swap them and report back.
 
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Old 02-20-15, 03:56 PM
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Sonofabit%&! Swapped thermostats between the upstairs and downstairs and the fault transferred between systems. Check, cancel the service call and order a new stat. Before I do that, how about I verify settings. The computer is too far away, I will just yank it off the wall and take it with me... That is when I noticed the Rc pin bent almost completely at 90 degrees and it wasn't dropping into the receptacle.

It is awful hard for 24vdc to jump an air gap! Problem solved guys, thanks for your time.
 
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Old 02-20-15, 03:58 PM
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If all problems were so easy to solve. Thanks for letting us know the outcome.
 
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Old 02-20-15, 06:41 PM
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Good call Grady, I will swap them and report back.
Even the blind squirrel finds a nut once in a while. Thanks.

Betcha next time you have a problem, one of the first things you'll do is to swap stats.
 
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