Gas and Oil Home Heating Furnaces - Another "gas furnace won't stay lit " question..
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12-25-01, 04:27 AM
Hi, I have a Magic chef forced air gas furnace(EG7A75D-7) that will not light, or stay lit.
Last winter I had this same problem where the thermostat would be sending signal, but the furnace pilot would not light. After playing with it for a while i was convinced it was the limit switch. So I did the famous "take it apart, stare at it, and put it back together" routine(both the limit switch and the flame sensor). To my surprise it suddenly started operating correctly again.. Well this year, after reading 10 or 20 post on this page, I'm thinking flame sensor. This is what I've tried.
I could smell a small amount of gas after the thermostat had been on a while, so I manuallyt lit the pilot(it has a spark Ignition system). The pilot would light, the burner would light, and the fan would come on. The system would run for about five minutes, and then the burner and pilot would go out. The fan would run for a few more minutes and then stop(not yet to temp.), leaving the thermostat with the light on, sending its useless signal. Thinking the limit switch is just a switch, I tried jumping the wires to it. Same results... One strange thing did happen. I had the limit switch out of the duct, and I had did my manually lighting routine, with the same out come as before. I proceded to reinstall the switch, accidently I grounded the conection as i inserted it. PooF the burner lit up, and the thing worked fine for three days. But today it stopped and is doing the same thing again....I know its something simple, but not 100% sure what it is. Thanks for any help you can give. Dave
Last winter I had this same problem where the thermostat would be sending signal, but the furnace pilot would not light. After playing with it for a while i was convinced it was the limit switch. So I did the famous "take it apart, stare at it, and put it back together" routine(both the limit switch and the flame sensor). To my surprise it suddenly started operating correctly again.. Well this year, after reading 10 or 20 post on this page, I'm thinking flame sensor. This is what I've tried.
I could smell a small amount of gas after the thermostat had been on a while, so I manuallyt lit the pilot(it has a spark Ignition system). The pilot would light, the burner would light, and the fan would come on. The system would run for about five minutes, and then the burner and pilot would go out. The fan would run for a few more minutes and then stop(not yet to temp.), leaving the thermostat with the light on, sending its useless signal. Thinking the limit switch is just a switch, I tried jumping the wires to it. Same results... One strange thing did happen. I had the limit switch out of the duct, and I had did my manually lighting routine, with the same out come as before. I proceded to reinstall the switch, accidently I grounded the conection as i inserted it. PooF the burner lit up, and the thing worked fine for three days. But today it stopped and is doing the same thing again....I know its something simple, but not 100% sure what it is. Thanks for any help you can give. Dave
seabee57
12-25-01, 05:44 AM
CHECK TO SEE THAT THE GROUND WIRE COMING INTO THE FURNACE IS GOOD..MAKE SURE IF IT GOES AROUND A SCREW HEAD THAT IT IS NOT CORRODED OR LOOSE..THIS CAN CAUSE MANY PROBLEMS ON IGNITION..
12-26-01, 11:48 PM
Checked the ground, seems ok. Wondering if there's a way to check the ignition controller without removing it?.......