wrote in message
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On Oct 22, 5:01 pm, "Douger" wrote:
"dss" wrote in message

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Douger,

If you get one that says it doesn't work with heat pumps or multi-
stage furnaces it should just need the three wires. They are also
usually cheaper. If you have a multi-stage you may be hosed.

I'll probably be doing the same thing for my daughter when she buys a
new house, so let us know how it turns out.

dss

I'm not following you.
Are you saying I only need to connect 3 of the wires?

Typically you have 4 wires:

hot wire, ie current source
heat on
A/C on
fan on/off, ie so you can have the blower run all the time or only
when heat or AC makes it go on.

Your problem is very strange, because per above, nothing from the
thermostat should have an effect on the inducer fan. That is
controlled by the furnace contoller/logic board. The thermostat justs
connects the hot wire to the heat wire to tell the furnace to fire
up. From there, the furnace controller starts the inducer, turns on
the gas, ignites it, starts the blower, etc. When the thermostat
opens, the furnace starts the shutdown sequence.

How long have you let it just sit there with the inducer running after the
furnace shuts off?

Well, I'm not sure.
When I initially tested the heat setting with the new thermostat,
I didn't notice the inducer running on until, oh, maybe 5 minutes after the
heat shut off.
I waited maybe another 5 minutes for the inducer to shut off on it's own
before I manually shut it down with the rocker switch on front of the
furnace.

Does it just keep running indefinitely?

Not sure. I know with the old thermostat the inducer would shut down at the
same time the fan blower shut down (or maybe just before the fan shut down),
either way, the inducer never ran on after the furnace shut down with the
old thermostat connected.

The only thing I can possibly think of is I think some thermostats
steal small amounts of power from the circuit to keep batteries
charged. I don't think most of them do that, but believe some do.
It could be that having that small current flow even when the heat
circuit is essentially open is somehow disrupting the controller in
the furnace. But that seems a long shot.

Might be time to get a HVAC pro.

I think you may be right.

I just don't like the idea of getting jacked to the tune of $75 for a
service call & $50/HR. , for what I **know** will be a simple fix. (well,
simple for the HVAC guy anyway).