Can't stop fan from running on Honeywell Thermostadt

unc99 · Jun 28, 2015

We bought a house with a Honeywell thermostadt, and the fan keeps coming on without explanation (at least as I can figure out). We have tried setting the fan to "auto", yet it will still come on at times when the AC is not running. We have even tried turning the system "off" and yet the fan will still come on at times even with the system off. See attached two pictures which show that both "on" and "auto" are active under the "Fan" heading. When the "on" is lit up, we have not found anything that will make it turn off.

The thermostadt has scheduling control options, and i have spent a lot of time trying to see if perhaps the fan is scheduled to come on but I don't think this is the case. As noted in the pictures, I have switched the thermostadt to "permanent hold" so the scheduling is not applicable, but still cannot stop the fan from coming on.

When the fan is running and the "on" is lit up under the "Fan" heading, the only thing I have been able to do to stop it is to flip the breaker and remove all power to the air handler.

Any advice would be welcome. Thanks

HVAC_Marc · Jun 28, 2015

what else is the thermostat connected to? lots of other things will cause the fan to turn on and off.

timebuilder · Jun 28, 2015

I believe this will require a tech to go into the setup program.

BaldLoonie · Jun 28, 2015

No, it's in the temperature programming. Each time period can have a choice of auto, circ and on fan. The homeowner just needs to get into the scheduling and look at every period for one not set at auto.

timebuilder · Jun 28, 2015

I thought he said that he'd already looked at scheduling....

kdean1 · Jun 28, 2015

Do you have the manual for the thermostat? If not, you can find it online. Check each scheduled period to make sure it is not set for fan on. Some Honeywell thermostats have a "circ" mode to run the fan occassionally between cycles.

PS there is no letter D in thermostat.

BaldLoonie · Jun 28, 2015

Since it says ON and AUTO both, still say to check scheduling.

timebuilder · Jun 28, 2015

The vision pro will say auto when not calling, and will add ON when the call starts.

He should probably download the manual as mentioned above, and make sure each daily schedule says "auto".

buford · Jun 29, 2015

Might even be some add on fresh air intake system for ventilation. They were or may still be required in our state.

doug1111 · Jun 29, 2015

If you took the T/S off the wall does the fan stay running????

unc99 · Jul 7, 2015

Thanks to all for the responses. As many suspected, it was the scheduling. I turned all of the scheduling options to "auto" which solved the problem. I had thought that when I turned the temp setting to "permanent hold" that it bypassed the scheduling, but the scheduling was still turning the fan on. Thanks again.

Can't stop fan from running on Honeywell Thermostadt

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