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Denhoff,ND right in the center of the State | I have a Coleman furnace in our mobile home, last week the blower motor went out, so got a new one and replaced it, now the blower motor come on as soon as the thermostat calls for heat and runs constantly, even before the furnace has lit and even heated up the plenium, once the furnace has cooled down the blower quits. I am very puzzled to why this is, have talked to many service people and the Coleman Co. and seem to get no where, any help appreciated. Thanks, Terry |
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| A good furnace man should be called out. The plenum temp. switches control the on and off for the blower fan. They wait for temp to get high enough before
the blower comes on, and they wait a bit before shutting off. Get some help. |
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NW Montana | It sounds like an open rollout or fan center malfunction. how old is it and what model? |
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Minot ND | you just replace the the temp senser, i got mine from menards. |
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Denhoff,ND right in the center of the State | It is a 2001 model year, and the Model # is DGATO75BDF. |
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just a tish NE of central ND | Your furnace is light-years newer than mine was........Does that have a pilot light or electronic ignition?Mine had a pilot light. Id bet yours is eletronic(I come from the old school of hard knocks yet) LOL!
I'm not sure why you furnace runs the blower before it even warms up. That is just strange .But maybe the thermostat sends juice to the blower thermo-disc switches as soon as the thermostat calls for flame?But I suspect that the thermo-disc interrupts that current untill the plenum gets hot enough?
The Coleman I used to have had a heat sensor switch in the plenum above the firebox as well as a "overheat safety" switch which dropped the gas in case of blower failure and too much heat buildup in the plenum. I do remember going through the same problem you speak of. I seem to remember that my blower would kick on real easily as soon as the pilot light lit up the flame to the burner. But not before. We thought at the time that the motor that went bad on us was responsible for causing the blower switch that needs heat to activate to get ruined and it couldn't accurately sense the correct temp to do the switching. I got replacements at Whol's Electric I believe in Harvey or maybe at kellers plumbing in the same town....There should be a number and a temp range printed on them. Mine had two wire push on connectors on each switch.
Hope this helps.
Edited by School Of Hard Knock 11/25/2011 19:45
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NW Montana | What code is flashing on the control board? Nobody will help because of liability. It sounds like a bad IFC to me. sometimes a motor will take them out or lightning. Did you replace the capacitor with the motor? |
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Denhoff,ND right in the center of the State | It dont flash any codes, this model dont use a capacitor for the blower motor. What is a IFC, and what controls the fan to turn it on? Terry |
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NW Montana | Integrated furnace control and it turns the fan on and off as well as all other functions of the furnace. I believe it should have a slow flash during normal operation. It should say on the fan compartment cover. |
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West Union, Illinois | Keep in mind it's been close to 5 years since I did much service work and my memory is getting a bit foggy. Which fan is it you are talking about? If I remember correctly that furnace probably has a combustion air fan ( a small fan blowing air in to the combustion chamber) and a circulation air fan (blowing air through the house). The combustion air fan should act just as you described. It should kick on when the thermostat calls for heat, purge the combustion chamber of any gas setting around, then when the ignition starts up it would continue until either the burner lights OR if it does not light would purge any fuel gas from the combustion chamber. The circulaion fan usualy operates ttally independent of the other. It turns on when the temperature in the plenum is high enough to need heat moved and turn off when it cools down. If the air returning to the furnace is particularly cold it may cycle on and off repeatedl while the burner is going. ALSO I would suggest you look at this recall notice, also listed here, then contact the number given. |
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Hillsboro,Texas | Most new gas furnaces blower motors are timed on/off( adjustable 30/60/90 sec)....As Hard Knocks stated, combustion blower comes on before ignition and runs until the cycle is complete, so simply.. when you got ignition you should have the combustion blower running.. |
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Denhoff,ND right in the center of the State | Yes but both the combustion blower which purges the air and the circulating blower or fan run at the same time, even before the furnace has produced any heat. Terry |
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just a tish NE of central ND | bullhauler - 11/25/2011 23:03
Yes but both the combustion blower which purges the air and the circulating blower or fan run at the same time, even before the furnace has produced any heat. Terry
Have you located the thermo disc or temp sensing unit in the plenum that attaches to the fan motor?I'm still betting it needs replacing . I would bet that it is a single pole type thermostatic switch that would be normally open circuit at room temp and the circuit is designed to close at say .?? maybe 120- 135 degreese f and designed to open back up when the temp falls to that level again. That is what mine did. Its a cheap place to start compared to calling a service guy out to turn two screws and unplug / re plug two wires on that thermodisc.. And its a nice day to do it on too!It wont even freeze in the house yet if it is turned off!!!.
Good luck ss
Edited by School Of Hard Knock 11/26/2011 09:56
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Denhoff,ND right in the center of the State | The fan is actually controled by a circuit board, printed circuit, there is nothing else that the fan conects to, think I will try a new board, they are about $150.00, think when the old motor went bad it took out the board. Thanks, Terry |
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NW Montana | Terry the thermo discs and temp sensor all are in series and connect to the board unless it has a honeywell smart valve. Ifc = printed board. I would lean toward the board if any of the safeys are open it would not light. |
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Coleman mobile home furnace troubleshooting?
