No Fan On Chronotherm III

Hi Everyone, I have a question. I have a Honeywell Chronotherm III with a heatpump and a gas furnace for backup. The last couple of nights we have had sub-freezing weather here so the furnace has been active. I normally place the fan in the "on" position so the electronic air cleaner can do its job. The last two nights the fan has only come on when the furnace kicks in. If anyone has any ideas, I look forward to hearing them. Thanks in advance for your help.
MC
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Its not in the thermostat..
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Same set up that I have, Check the sub base wires and then reseat the tstat. Look for corrosion on the terminals that do the electrical connections on the tstat. Verify that it works or does not. Might be time to call someone. I agree it might not be in the tstat.
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I appreciate your help. If it isn't the thermostat, what else should I be looking for? The fan works fine when the heat kicks in, whether the tstat is in the on or auto position. Do you have any ideas on what the best and worst case scenarios would be? I assume dirty contacts would be a best case. ONce again thanks for all your help. I appreciate it.
Mike C.
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Well..lets see....
Its like this...
Heat pump with gas second stage..EVERY one I have EVER wired works like this..
Heat pump is running,...seconds stage is called for, the entire unit shuts down, and the gas unit fires, and when temp is reached or the timer expires, the unit starts again, and the heat pump will start back up when the gas unit is running, and all shut off when setpoint reached. This is due to the fossil fuel switch wiring... Now..since in a case like this, the thermostat is nothing but an off, and on switch, and with a gas furnace, there are two sets of controls for the fan...umm...sounds like ones not working. Also, since you have given no information to go on, it would be damn hard to tell you whats wrong, other than what you have been told. 99% of the time, its not the thermostat, altho Home Depot, and Lowes would love you to think otherwise.
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If what I suggested does not work then, it is time to call an expert. Not exactly my expertise....
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