Gas furnace startup


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Old 11-08-13, 01:31 PM
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Gas furnace startup

Read the post from the guy in California about intermittent startup trouble. I have a similar issue... However, the "pressure switch" that was shown is dissimilar to the one I have. When my furnace doesn't start, I open the unit, notice the trouble code, turn off the power.... There is a small "switch" that is mounted vertically. I stick my finger up inside and give it a spin. After restoring the unit, it runs fine, and may do so for many days. The switch spins smoothly without any hesitant spots. I'm guessing this is a centrifugal switch. I also read about startup and shut down issues for restart. Could my switch problem actually be up or downstream from the unit I spin? How do I check the switch for failure if it works most of the time?
 
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Old 11-08-13, 01:56 PM
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Welcome to the forums.

I have no idea what switch spins. It would be a first for me.
The draft inducer blower spins. Is that what you are referring too ?

If you are talking about that round wheel on the end of the motor... that's your draft inducer. As soon as your thermostat calls for heat that blower should be up to full speed in a few seconds. It must be running at normal speed for furnace to ignite. If you have to manually push/turn it then it needs to be replaced.
 
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Old 11-08-13, 05:51 PM
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No, this is not the circulating blower. The unit I refer to is about the size of a soup can. It may be part of a purge system, and comes on before the burner lights or the blower motor starts turning. I'll research a part name and/or number, but the unit may not be the problem. I hate swapping out parts only to have the problem unfixed.
 
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Old 11-08-13, 08:57 PM
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Yes....a flue purge system that is called a draft inducer blower. It is the first thing to come on when heat is called for. It discharges hot exhaust gases out into the flue and runs VERY hot. With age they burn up and bearings start to fail/dry out.

You can shoot us a picture and post it. http://www.doityourself.com/forum/el...-pictures.html
 
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Old 11-09-13, 09:18 AM
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Please post the make/model of your furnace. Is the induction motor on your furnace similar to the photo I attached?
 
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