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JackBP 12-15-2010 11:03 PM

No Aux heat with American Std HP/Trane AH and Honeywell IAQ FREEZING!!!!
1 Attachment(s)
Hello all. hope you are in a nice warm house without this kind of trouble. I have a problem with our heating system, because the aux heat does not come on and the heat pump can't do it all when its 20 degrees here with a 20 mph breeze.
American std heat pump unit: 2A6H3018-060
Trane air handler: 2TEC3F36B1000AA
Thermostat: Honeywell VisionPro IAQ TH9421C1004 with EIM
and the outdoor temp sensor.

Attached schematic is the way the system is wired.

We had a tech come by from our original contractor 'Cliff's', but the guy had not worked with honeywell stuff before, and some other guys from cliffs had put in the thermostat, EIM and temp sensor.

1. is the system wired properly? see attached or image on webpage:

2. are these IAQ settings right for this system?
0172-system type - 2 (heat pump)
0176 - heat or heat pump aux stages - 2
0200 - backup heat - 0 (electric heat)

I currently have the temp lockout such that the aux heat does not come on, just because when the t-stat tries to go to aux heat, it does, but the aux heat does not 'engage'.

the tech says that when he bypasses the EIM, he can get the aux heat to come on. he says it is an EIM problem, but the EIM is brand new. for troubleshooting the honeywell documentation only states that if the EIM onboard led blinks rapidly, and itermittently, then its functioning okay. Thats what it does.

any help is greatly appreciated.

beenthere 12-16-2010 05:45 AM

W2 should go to W1 of the air handler, and W3 should go to W2 and W3 of the air handler.

Your settings are correct. Make sure no wire insulation is under the screws of the EIM.

Put the stat into test mode, and see if it turns on the aux heat then.

If the heat still won;t come on then. Recheck all of your settings again. If they are all ok, you may have a bad EIM or stat. It has a 5 year warranty. Get a new one.

JackBP 12-17-2010 11:01 PM

update on schemayic and followup question
2 Attachment(s)
Attached is the revised schematic. I discovered labels on the connectors, and I've updated the schematic. Plus attached is the Trane schematic for the air handler.

Question: should a white wire going from the aux heat box (W1) go to W2/aux on the EIM AND to the heat pump unit outside?


beenthere 12-18-2010 03:50 AM

Yes, the W2 of the EIM and the white from the outdoor unit should both go to W1 of the air handler.

That way, when the unit goes into defrost, it brings on one of the strip heaters to prevent cold air from being blown out of the registers.

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