Furnace fan operation


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Old 07-23-14, 05:21 PM
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Furnace fan operation

Carrier Infinity 96 furnace less than five years old with basic Carrier programmable thermostat. The builder said I should always leave the fan setting On (Off is the auto fan setting). Should fan always be left on?

My knowledge of forced air furnace operation is very limited, but it seems to me that the furnace is kicking in and blowing an awful lot of the time even with both heat and AC turned off...is this normal behavior? I just don't think I should notice the furnace operating in the summer months like I do on the winter.
 
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Old 07-23-14, 06:38 PM
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You would get high humidity problems if you had the fan to the On position in my area but I would refer you to someone that lives further north since I have never been north of Dallas. Perhaps PJ, Grady or Gunguy can offer some advice.
 
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Old 07-23-14, 06:48 PM
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The only reason to run FAN ONLY is if you have major temperature differences in your house and you were trying to equalize them. Like Houston mentioned.... running it continuous in the summer definitely raises the humidity level.

the furnace is kicking in and blowing an awful lot of the time even with both heat and AC turned off
If you have the thermostat set to FAN ON it should be running 24 hours a day. If you have it in auto mode then it should only blow when heat or A/C is called for.

So...I'm questioning the "kicking in" part.
 
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Old 07-23-14, 07:12 PM
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Thanks for the reply guys. I have tried this previously, but now that I know it shouldn't kick in until called for I'm going to monitor the fan in auto fan mode with both heat and AC turned off, and post back tomorrow with result.

Just a thought, the thermostat has winter times and temps programmed into it, but with heat/AC turned off the program schedule shouldn't set off the blower throughout the day, correct?
 
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Old 07-23-14, 07:21 PM
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but with heat/AC turned off the program schedule shouldn't set off the blower throughout the day, correct?
That is correct.

Just had a thought..... do you have an automatic humidifier that may be forcing the blower on ?
 
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Old 07-23-14, 07:48 PM
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There is a "Healthy Climate Solutions" humidifier attached to the furnace. My digital hygrometer is reading around 50% R.H. upstairs and the dial on the humidifier downstairs is set at 35%.
 
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Old 07-23-14, 07:58 PM
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If you find out that when heat and A/C are turned off and you still have the blower coming on..... see if you can turn off or disable the humidifier.
 
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Old 07-23-14, 08:10 PM
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Ok thanks, I'll see what happens and post back later.
 
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Old 07-25-14, 08:06 PM
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With everything off, the blower stills turns on periodically. I'm not sure how to disable the humidifier itself, and I don't want to start disconnecting wires...maybe you can provide a little direction before I get myself into trouble.
 
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Old 07-25-14, 08:14 PM
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I don't know what model your humidifier is so I can't give you exact information but try turning the humidistat knob to the lowest setting.
 
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Old 07-28-14, 07:23 PM
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I turned the humidifier down to the lowest setting, and the blower is still turning on periodically throughout the day (and night).
 
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Old 07-28-14, 07:56 PM
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AirCyclerŽ g2 - Furnace Fan Timer with optional Damper and Exhaust Fan | AirCycler

Do you see an air cycler installed anywhere around your furnace?

Name:  AirCycler-g2.JPG
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Old 07-28-14, 09:20 PM
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I don't see an air cycler - I've attached a picture.

[ATTACH=CONFIG]35479[/ATTACH]
 
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Old 07-29-14, 10:25 AM
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If you had one it would interrupt the G signal from the stat and you might be able to see this at the low voltage connections in the furnace.
 
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Old 07-29-14, 10:52 AM
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Just a basic humidifier from what I can tell. Any chance my thermostat on the main floor is faulty, maybe worth trying to replace that?
 
 

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