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dit 07-16-2010 12:31 PM

Worried about attic fan
Should it be running non-stop including all night? I am in NC and it is hot and very humid. But I don't recall it running constantly without a break.

I never paid much attention to it before, so I don't know if it has always done this in the summer or not. But last night I noticed it was still going and had not shut off even at 5AM (restless night).

Normal? Thermostat issue? Thoughts appreciated. Oh, and if it's not normal, who to call....HVAC or some other type of contractor? I had it replaced a few years ago, but can't remember who was involved.

NitroNate 07-16-2010 12:36 PM

yeah could be the thermostat connected to the fan. mine used to run more and more and then all the time during mid-summer until i went up there and re-adjusted it. it gets really hot here so i set it at about 110 degrees.

DexterII 07-16-2010 01:27 PM

It certainly is hot, and has stayed that way for a while, so very possible that nothing is wrong, but it's always best to check, and you can perform the initial diagnosis yourself.

There surely is a switch and/or a thermostat, someplace in the electrical circuit between your main panel and your fan, so the first thing that I would do is to go into the attic, and look for the switch or the thermostat, either on the fan itself, or in the wires leading to it. Ideally, you will want to do this early in the morning, when the temperature in the attic is at it's lowest, so that, assuming you find a thermostat, you can dial it up, and see if the fan shuts off. Then, just to ensure that the thermostat is not out of whack, you should take a regular household thermometer with you, to see if the readings are close. If you find only a swithch, or if the thermostat readings appear to be off, I suggest that you call your regular your heating and cooling guy, who can install a thermostat for you.

Just be careful that you do not spend too much time up there. The heat in an attic can overcome you quicker than you may think on these hot days of summer.

Yoyizit 07-16-2010 04:01 PM

If it doesn't shut off ever, or with an absolutely waterproof icebag on the housing [give it a few minutes] the 'stat contacts may be welded.

With power off see if you can gently open the 'stat contacts with a toothpick. A little magnet that provides hysteresis for the bimetallic switch will resist your force.

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