Coleman furnace fan keeps turning off and on every 10 seconds...
Coleman Furnace Model 7680B Series 856 Sometimes this furnace runs perfectly, but about once a day the fan seems to get stuck or something and it keeps going on and off every 5 to 10 seconds---when it does this there is no fire in the box, just the pilot light is on. I have to turn ithe furnace off for about 30 minutes and then it will run okay for about six hours or until it does it again. Any ideas? It has 3 limit switches that I am aware of.
Re: Coleman furnace fan keeps turning off and on every 10...
Clean your heat/flame sensor with sand paper or steal wool. If the sensor is dirty, it won't detect the heat from the flame and it shuts the gas off. Clean the soot and junk off the sensor and it should work fine. I have to clean mine every year. After spending hundreds of $$ every yr on tech calls..I figured out the problem and in 30 sec I'm up and running again.
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... Furnace, Mark, 9-12-07. Need wiring diagram for coleman furnace Model # 7700B856 .... Amanda, 11-10-11. I need a wiring diagram for a Coleman evconpresidential model 7956c856 ... Need wireing diagram for coleman 3500a916 ...
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You need a themocouple, it's a cheap $10.00 part you can get at any hardware store, you have a standing pilot light furnace like mine, if your handy and safe you can put one in easy, youtube is loaded with videos on how to do it. These other answers are wrong for your unit.
Hello, this sounds like it may be a problem with the relay on the integrated control board. it sticks occassionally and therefore the fan will keep running, when you hit the front side it causes the relay to open and thus the motor turns off. only option is to replace the control board as the relay cannot be replaced byitself.
The chances are that the furnace was running when the power went out. This will cause the high limit switch to cutout and needs to be manually reset.
You will find that switch in the blower compartment near the blower. Usually somewher near the highest point of the cabinet.
Push the little red button firmly till it clicks.
When the power goes out while the furnace is running the heat builds up because the blower shuts down immediately and causes this limit switch to cut out.
If you have a electric tester you can also follow the low voltage circuit till you find the open switch. Ther is usually a wiring schematic on the door cover of most furnaces.
I hope that this will help you to solve your problem!
This sounds like a bad heat exchanger. It is possible that you do not see the crack because the crack is closed when the heat exchanger is cold (or room temp). Allow the furnace to heat up, this will allow the expansion of the crack. Turn the power off and examine the heat exchanger while it is still hot.
first off buy yourself a honeywell stat, in my personal opinion lux stats are garbage, I have run into so many that are bad stats !!! but as far as your fan not shuting down, sounds to me like your fan center on your circuit board is bad and will not shut down the fan when needed, you will have to replace the circuit board, as the fan center is a part of the whole of the circuit board, hope that helps