Coleman Evcon Furnace Limit Switch Error


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Old 02-25-07, 03:20 PM
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Coleman Evcon Furnace Limit Switch Error

I have a Coleman Evcon Funace (Model G8C07512MUB11A, 3 Burner, 75,000BTU). The problem I am having is that the burner keeps kicking off and the blower fan and exhaust fan keep running. The status light on the circuit board flasher 4 times (open limit switch error). I have bypassed the limit switch, but I still get the error. The filters are clean. The pressure switch is working. If I leave the power off to the furnace for about 15 minutes, the furnace will start back up but then after about 5 to 10 minutes the burner turns off but the fans keep running and the status light blinks 4 times. While the status light is blinking, I check continuity of the limit switch and it says it is closed, not open as the circuit board says. Any help would be greatly appreciated. Thanks.
 
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Old 02-26-07, 04:36 PM
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I had this same deal going on, with a Coleman (a newer one) in a mobile home, and it would limit out, the 4 flashes, I'd reset it and it would go again, but the trailer could never get to set temp. Turns out it was a defective Maplechase thermostat. Test and see.
 
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Old 02-26-07, 05:28 PM
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Check for other limit switches in the string. While it may not be a main limit, there may be a rollout tripping, although they are usually manual reset. Check for a limit switch in the blower housing.
 
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Old 02-27-07, 08:48 PM
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I have noticed now that if I leave the access panel off of the furnace (had panel off to make it easier to see the burner flames and circuit board with status light) , it has been running fine with no errors. I reinstalled the access panel last night, and within 15 minutes or so, it tripped the limit switch error again. So I removed the panel again and it has been working fine today. Seems like it has something to do with either airflow, ventilation, or pressure. I don't see anything else for why the access panel would make a difference. As for the rollout sensors, I did check and clean them previously with no effect, plus they have there own error code for this furnace. Thanks for your replies.
 
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Old 02-28-07, 03:54 PM
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Is this the kind of furnace in a mobile home that really has no cold air return ducts, and the filters are in the door where the air must pass into the furnace?
 
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Old 02-28-07, 06:16 PM
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No, this is actually for a residential house. I do have central air and cold air duct returns. The filters are located at the top of the furnace in a Honeywell electronic air cleaner. Thanks.
 
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Old 03-01-07, 02:50 PM
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Error Code

I suspect the problem to be with the board rather than the limit. With the panel off there is probably just enough extra cooling to keep it working properly. You might want to check your warranty if the furnace is under 5 yrs. old.
 
 

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