gas furnace main blower switching rotation

Problems related to residential installations.

gas furnace main blower switching rotation

Postby umniy2000 » Sat Oct 22, 2011 6:06 pm

I’ve noticed that my York gas furnace does not heat up the house properly. At first, I thought that the air flow velocity was not high enough and I still don’t know if it is. Nothing has been changed since the last winter and the AC worked fine this summer.
I opened the cabinet and inspected the operation. The sequence is - my digital thermostat calls for heat-the induced draft blower comes ON-the pilot light comes ON-the burners light up-the fan limit switch starts rotating-it reaches the ON position-the main blower turns ON-the limit switch keeps rotating and gas burning. But at this point something strange - it very quickly reaches the Limit position and shuts the gas OFF. The main blower keeps blowing, but at some moment it all of a sudden stops and by itself reverses rotation. And it may do reversing back and forth a few times in the row, until it finally stops completely.
I don’t believe it should EVER reverse, but I may be wrong. The fact that the limit switch very quickly reaches the Limit position is also not good and I could try either increasing it or replacing (it is about 25 years old. The settings - 90-140-190.)
Before I do more troubleshooting, I need to know if motor reversing is a problem and what I should be looking for.
umniy2000
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- gas furnace main blower switching rotation

Postby umniy2000 » Sat Oct 22, 2011 6:39 pm

This is an addition to my - someone suggested that it may be a bad blower motor capacitor. I visually checked it - it has white rundown trace on its side. Does it make sense? I replaced the motor and the capacitor in 2008.
umniy2000
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Joined: Sat Oct 22, 2011 5:59 pm


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