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posted
Not sure if this is the right place to post this but here goes:

The fan to the HVAC unit keeps turning itself off and on even though the thermostat on the wall is set to OFF (not HEAT or COOL) and the fan is set to AUTO (not ON). It does this more in the evenings/night than during the day. I asked the previous owner about it and he didn't know what I was talking about.

What is causing this and how can I stop it or is this somehow normal?

I don't know what brand the heater is though it is for propane and an electronic ignition. The thermostat on the wall is White Rodgers.

TIA.
 
Posts: 6052 | Registered: Feb 08, 2006Reply With QuoteReport This Post
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Last night, for example, it had a field night, so to speak. The fan would run, run, run, shut itself off for a few seconds, then "thump," it would start itself back up again, run for a few minutes, shut itself off for a couple of seconds, then "thump"... All night.
 
Posts: 6052 | Registered: Feb 08, 2006Reply With QuoteReport This Post
Picture of conrad
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Not sure if you have an outside compressor fan that is running, or if you are talking about the fan on the ac/furnace unit?

Either way, this would get me to call a repair person.
It may simply be a faulty thermostat, but compressors are EXPENSIVE as well as fan motors. Plus the possibility of a fire thrown into the mix. I would bite the bullet and call a pro.
 
Posts: 9446 | Location: Plains & Mountains | Registered: Jun 08, 2003Reply With QuoteReport This Post
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I think it's the fan on the unit itself, Conrad. It's just odd, like it's programmed to do it. Seems to start in the early evening though it has been running continuously today. Confusing.

Anyway, I called the service company and they will come out Tuesday afternoon.
 
Posts: 6052 | Registered: Feb 08, 2006Reply With QuoteReport This Post
Picture of conrad
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I think calling them is appropriate.
If you should want or NEED to shut it off in the meantime, there is often a fan power switch on the unit itself. All else fails, the breaker box or fuse box will have the AC/furnace switch that can be switched off.
 
Posts: 9446 | Location: Plains & Mountains | Registered: Jun 08, 2003Reply With QuoteReport This Post
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Wow, that is a brilliant idea, Conrad, the breaker box thing, I never thought of that. I am too frightened to try to open the unit to look for a fan switch but am comfortable hunting down the breaker box and flipping the switch there. The fan shut itself off and is back on again.

Anyway, thank you.
 
Posts: 6052 | Registered: Feb 08, 2006Reply With QuoteReport This Post
Picture of conrad
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Whoa! Did I hear you right?
After you shut off the breaker and left it off...the fan still came back on???

Could this possibly be a "whole house fan" in the attic that you are hearing??? exhausting hot air out of the attic, in other words?
 
Posts: 9446 | Location: Plains & Mountains | Registered: Jun 08, 2003Reply With QuoteReport This Post
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No, I haven't gone to the breaker yet. Actually, the fan is now off. Ran all morning and now is off. Maybe auto shut off at 1:00 PM? I WILL go to the breaker to find the unit but I haven't done that yet.

Oh, here it is, back on again. Geez. I haven't gone to the breaker yet.
 
Posts: 6052 | Registered: Feb 08, 2006Reply With QuoteReport This Post
Picture of conrad
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Oh...ok.
LOL!
 
Posts: 9446 | Location: Plains & Mountains | Registered: Jun 08, 2003Reply With QuoteReport This Post
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When I searched for your problem online someone said their problem was caused by a programmable thermostat (new house, they did not know what it was programmed for)that was overriding the off button. Do you have a programmable thermostat? I found the manual for ours (in new house) on the Internet.
 
Posts: 6750 | Location: North MN & Northern AR | Registered: Oct 01, 2002Reply With QuoteReport This Post
Picture of conrad
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That sounds like a reasonable guess, metwo.
All the programmable ones I am familiar with, will not operate, if the unit is actually OFF?
 
Posts: 9446 | Location: Plains & Mountains | Registered: Jun 08, 2003Reply With QuoteReport This Post
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So the HVAC fellow just left. He had never heard of a unit going on and off, etc. He didn't know what was wrong so he said the first thing we should do is change the thermostat. So, he did.

Fingers crossed, that is the fix.

If it isn't, I do know where the breaker is as I had blessed peace (turned the darn thing off) yesterday.
 
Posts: 6052 | Registered: Feb 08, 2006Reply With QuoteReport This Post
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Well, crum, crum, crum. That did not fix the unit. The fan is still going on and off so just turned it off at the breaker. He said today that he wouldn't be able to come back until Saturday. I will call him tomorrow.
 
Posts: 6052 | Registered: Feb 08, 2006Reply With QuoteReport This Post
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My hubby the retired HVAC guy says there may be a short somewhere in the thermostat wire between the stat and the furnace. It can be checked for a short with an ohm meter. Your repair guy should know that. The wire can be damaged during renovations... Any time when nails are driven through walls, during demolition, etc. Has that happened lately? It's a light-gauge wire that can be easily nicked or broken.
 
Posts: 4362 | Location: zone 6b, Missouri | Registered: Sep 19, 2002Reply With QuoteReport This Post
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No, no demolition or remodeling of any kind. It's weird, like it's programmed to do it because it doesn't generally happen during the day but starts around 7:45-8:00 PM at night. Some nights it does it, others, it doesn't.

Well, just hope he can fix it. Turned the breaker off so all is quiet.
 
Posts: 6052 | Registered: Feb 08, 2006Reply With QuoteReport This Post
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Ok, so he was back again Saturday and after two trips to the supply warehouse, fixed it. First, he found a loose wire but the board tested "good" so after trip 1 from the supply warehouse and wire repair, the board showed "not good" so he had to go get one of those. It seems to be acting normally now. :-)
 
Posts: 6052 | Registered: Feb 08, 2006Reply With QuoteReport This Post
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Thanks for telling us. I was wondering how you made out.
 
Posts: 6750 | Location: North MN & Northern AR | Registered: Oct 01, 2002Reply With QuoteReport This Post
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