Short cycling, with longer run time each time it cycles

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bigd85743
Posts: 3
Joined: Fri Nov 26, 2010 3:08 pm
Location: Arizona

MGHA-056ABFC-02,
S/N: MGH9507-03342

Fired the heater up for the first time this year a few days ago and everything worked fine except the unit was short cycling. Today when I turned it on to begin to figure out the problem, it would come on for 30 seconds then off for 30 seconds and then repeat the cycle. So I let it cycle a bit to get some heat in the house and after a couple of hours it is still cycling but now it is running for longer periods of time with the same 30 second off cycle. The latest on cycle was just short of 10 minutes followed by 30 seconds off then back on again. I went ahead and changed the fan switch thinking that was the cause of the problem but that didn't help. Any ideas on where to go form here?

Don
Don
MGHA-056ABFC-02,
S/N: MGH9507-03342
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Robert
Moderator
Posts: 6413
Joined: Wed Feb 28, 2007 12:07 am
Location: Tennessee

Hi Don,

Is it just the fan going on/off or fan and burner ?


Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?
bigd85743
Posts: 3
Joined: Fri Nov 26, 2010 3:08 pm
Location: Arizona

Robert

It's just the fan. The burner stays lit.

One other thing I have tried is eliminating the thermostat thinking that might be it as well but I get the same results without it
Don
MGHA-056ABFC-02,
S/N: MGH9507-03342
User avatar
Robert
Moderator
Posts: 6413
Joined: Wed Feb 28, 2007 12:07 am
Location: Tennessee

The first thing you would need to know is IF the fan switch is actually opening and closing.

Once the fan switch closes and energizes the blower, it will remain running until a period after the burner goes out.

IF fan switch is opening/closing while burner is still lit, it is bad or it is doing the job it was designed for.

Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?
bigd85743
Posts: 3
Joined: Fri Nov 26, 2010 3:08 pm
Location: Arizona

Robert
First off, thanks for the help. The switch is closing, its just not staying closed for some reason. I'm starting to wonder about the fan switch and whether or not it is the correct one. If it's not too much trouble, can you find the part number for the correct switch for my unit and pass it along to me?
Don
MGHA-056ABFC-02,
S/N: MGH9507-03342
User avatar
Robert
Moderator
Posts: 6413
Joined: Wed Feb 28, 2007 12:07 am
Location: Tennessee

Hi Don,

Fan Switch # 626337



Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?
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