Furnace/blower motor grief


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Old 11-08-08, 10:58 AM
J
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Furnace/blower motor grief

Good day everyone i have a furnace problem i hope someone can help with. The furnace is an older Tempstar but not old enough to have a pilot light. Now when the furnace kicks in, the flame comes on and just when the main blower motor is going to kick in...everything shuts down. Th smaller blower motor with what looks like a pressure activated switch works..it comes on slightly before the flame and every thing but just not the big motor in the bottom part of the furnace.

Thank you in advance.


Joe
 
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Old 11-08-08, 11:46 AM
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Blower

The problem could be the motor or whatever controls it be it some sort of timer or temperature control. Do you have a volt meter & know how to use it?
 
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Old 11-08-08, 12:13 PM
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Yes i have and know how to use one, also i just noticed that when i tried to turn on the blower motor to "ON" i got nothing. So the blower won't kick in in auto or manually now. I went down and turned the fan by hand and it turned freely and ran out its spin so i am guess the bearings are good on the motor. I have 110 going into the furnace and from the transformer i have 24v at all the correct connections that are marked on my "Honeywell" control box of some sort.

~Joe
 
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Old 11-09-08, 06:05 AM
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Fan Problem

You need to trace the current path for the motor. There should be a wiring diagram somewhere (often on the inside of the blower door). With the fan switch set to "on", & the blower door closed, check for 120v from wherever the fan would get it's power.

A way to check the motor is to use an ohm meter. Put one lead on the neutral, the other on the low speed wire (red), & note the reading. Repeat with each speed. Ohms should go up as fan speed goes up. The nice thing about this method is it is done with the power off. If your meter has a capactior test function, it would be a good idea to check the capacitor as well.
 
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Old 11-10-08, 10:57 AM
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Okay for some reason i unpluged a wire on the honeywell box mounted in the lower area of the furnace....the blower fan came on..so now i can turn it on and off up stairs on the thermostat...but the run time is extremely low on it now once the furnace fires up. Is there a way i can set this or is there another problem inside some where? I will do the things you said and get a power reading for you also.

~Joe
 
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Old 11-10-08, 04:19 PM
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Wiring diagram

If you will supply me with a model number of the furnace, I may be able to get a wiring diagram online. Knowing which wire you pulled off would be a big help.
 
 

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