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Honeywell Thermostat E/AUX Connection

Posted by davidpj (My Page) on
Mon, Nov 12, 12 at 13:25


I'm replacing a Honeywell VisonPRO 8320U1008 with a Honeywell VisionPRO TH8321U1097 on my 2H/1C heat pump and I discovered that the E and Aux terminals are now combined into a single E/AUX terminal on the new thermostat. The thermostat that's being replaced has a black wire on E and a white wire on Aux.

I'm thinking of attaching both wires to the single terminal, or, leaving off the black Emergency heat wire.

The thermostat is in a basement zone off the main system. I don't think I'll ever have the need for aux or emergency heat in the basement.

Can you please suggest how best to configure this new thermostat for proper aux and emergency heat? Thanks.

Follow-Up Postings:

RE: Honeywell Thermostat E/AUX Connection

Almost impossible to answer without knowing what's connected at the other end.
While often aux and emergency were the same heat source, the second stage, sometimes had a bypass to operate the aux if there was a system problem or you manually switched to emergency to bypass the first stage.

It may work putting wires together in conjunction with some advanced installer settings on the stat, but wiring and operation would need to be known on the system end.

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