Heating/cooling fan won't shut off unless temp manually moved.

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Old 11-24-15, 07:51 PM
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Heating/cooling fan won't shut off unless temp manually moved.

I know his may be an age old problem but I can't find a post describing my exact problem.
equipment - New Lennox Heat Pump unit.
Thermostat - White Rodgers heat pump thermostat (6 months old)

Problem example: Set point set at 69 degrees. Unit will come on normally with fan on, heat strips on and heat pump compressor energizes.

When inside heat reaches 69 degrees, thermostat clicks and heat strips turn off and outside compressor de-energizes but,,,,, fan continues to run and will run all night if temp stay at 69 or below. If temp falls below 69 set point, heat strips will again come on and compressor with energize again.
Cycle will continue with the same result,,,,, fan will not shut off.

** If I manually raise the temperature myself to 70 degrees, the fan will turn off. *** Process will repeat itself no matter what temp I set it at.

Fan is in Auto setting, Control is in Heat setting, not emergency setting.

You guys have any idea what my problem might be? I would suspect the thermostat but I had the same problem with the previously installed unit and another thermostat. Bad wiring / shorting out? If wiring were shorted, fan wouldn't shut off when I raise the temp manually.

I tried changing the batteries in thermostat as one guy suggested. Put in new thermostat? I could try that again, but hate to go through the expense and I have two of the same thermostats (upstairs and downstairs). Have to teach spouse to use yet another thermostat. Not what I really want to do! :NO NO NO:

ANY ideas would be helpful! Thanks!
 
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Old 11-24-15, 07:59 PM
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Try removing the thermostat when the fan is stuck on and see if it shuts off. You could swap the two thermostat since you have two of the same but I'm guessing when you pull the stat off.... the fan will stay running.

In that case you probably have a defective heat strip sequencer. It's a fancy name for a time delay fan and heat element relay.

The model number of the air handler would be helpful.
 
 

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