My furnace cycles too often

dkobel · Wed Oct 28, 2009 12:22 pm

I have a Coleman furnace, Model # 9766A856. It seems to turn on and off quite a bit. I was told to check the stack to check for obstructions such as birds or bee hives, but al that was clear. I was told then it may be the limit switch. I have not replaced that. I thought that it may be the thermostat, so I installed a programmable thermostat. None of these fixed the short timed cycles. Any clue of what to do next?

furnaceman · Wed Oct 28, 2009 2:14 pm

hi, can u be more specific, as to y u think it is cycling 2 quickly?
r we talking about starting and stopping with a minute or so, or r we talking about u think its running for 2 short a cycle, then starting back up?

don't take this wrong, but have u changed the filter, had the blower wheel cleaned, or do u have a vent or 2 that is covered, check those first. then get back 2 us, also make sure there is no draft hitting the t-stat or direct sunlight. I had a call last week where a customer's dryer vent was un hooked, and the t-stat was 5 feet from it, the hot air shut it off, but then when dryer shut off it started again, vent fixed, no moreproblems.

dkobel · Thu Oct 29, 2009 8:56 pm

There is no filter. Blower wheel is clean. No vents covered. I guess the best way I can describe it is that sometimes the heat will come on for a few minutes, turn off for a minute, then come back on in a minute. It doesn't always do it, but then again I don't constantly pay attention to it.
I haven't lived in a home that has forced air in years, but I know it's just not right. The thermostat is in a good spot, so I don't think that is it, and the dryer is at the other end of the home, so I'm good there.

Robert · Fri Oct 30, 2009 5:42 am

Hi,

No filter is a definite problem, that is a must. Can you recheck model number, the number given is not a valid number.

Thanks,
Robert

dkobel · Fri Oct 30, 2009 6:03 pm

Sorry, I switched the numbers on the model number. The # 7966 A856. I don't know exactly where the filter would go. I just got this place in late August, and the guy who owned it before wasn't a lot of help. Not a very clean person either. ewww

Robert · Fri Oct 30, 2009 11:27 pm

Hi,

Is it just the blower turning on and off or the burner also ? Will send filter info along with any other help at same time once I know for sure what is happening.

Thanks,
Robert

dkobel · Sun Nov 01, 2009 7:59 pm

It's mostly the fan that cycles. It only happens once in a while, but it is annoying, and I'm sure it's not right.

Robert · Mon Nov 02, 2009 3:27 am

Hi,

I would start by checking the fan switch, back wall of control box, should be switch on the left.

Fan Switch # 7975-3281 can be seen and ordered through PayPal from left side of this page:

http://www.mobilehomerepair.com/ColemanGas.html

Thanks,
Robert