If Thermostat is set to OFF can Fan still come on automaticly?


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Old 01-31-14, 08:10 AM
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If Thermostat is set to OFF can Fan still come on automaticly?

If the thermostat for the HVAC (Goodman Heat Pump) is set to the off position and the fan switch set to Auto, is it possible that the air handler fan could still be cycling on and off even though no heating or cooling is being called for ?
 
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Old 01-31-14, 08:40 AM
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Welcome to the forums.

It shouldn't be cycling unless there is an intermittent problem or the furnace itself is still hot from the burner recently shutting off.

Cycling how..... like on for a few seconds off for a few seconds. On for 15 minutes..... etc.
 
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Old 01-31-14, 12:44 PM
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Fan cycleing with unit off

HI thanks for your reply:
I'm actually trying to trace down a power usage in a closed up cabin that I can't get to for a few weeks. The electric bill keeps showing about 3KWH of use per day. Everything is turned off at the main panel except for two heat pumps that were turned off only at the thermostat.
Since nothing else is on and the power consumption is two low for the actual units to be running I was wondering if it could be the fan .
 
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Old 01-31-14, 08:59 PM
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Ahhh.... you should have said that from the start.

No..... the fans won't come on by themselves but what is using power is the crankcase heaters on the compressors. Since those are heat pumps the compressors are expected to run when it's cold. If the compressor wasn't heated it would not start because the compressor would be full of liquid freon and the oil would be very thick.
 
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Old 02-01-14, 08:29 AM
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Thanks’ you solved the mystery
I never even thought about the heaters. You definitely just made me a fan of diityourself.com.
 
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Old 02-01-14, 11:29 AM
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If I recall correctly, the average compressor crankcase heater draws about 60 watts, so doing the math, 2x60x24=2880 watts/day, which would pretty much match the 3 KWH per day you're noting.

To save that electricty, you could switch off the heatpumps at the breakers, but you'd need to turn the breakers back on for 24 hours before you intended to run the units, to allow the heaters to warm up the crankcases. The $10 a month you'd save on electricity could quickly be negated by damage to the compressors if you forgot to allow them to warm up before switching on the HVAC system.
 
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Old 02-02-14, 01:16 PM
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Thanks for the additional info and the heads up on the potential damage to the units if the heaters aren’t allowed to do their job. You guys gave me peace of mind and saved me a 500 mile trip.
 
 

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