Armstrong garage furnace main fan won't turn on


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Old 01-22-10, 01:50 PM
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Armstrong garage furnace main fan won't turn on

I have an Armstrong model # CGHA45AE-3 garage furnace whose main fan turns on only part time. I jiggle the wires to the fan and sometimes it turns on and sometimes not. I lightly tap the relay and nothing happens. The only way I can get the fan to start when the fan won't turn on is by hitting the side of it rather forcefully. I am not Fonzie and I don't want to be anymore. I have read the blogs in here about cleaning the flame sensor and while I agree with this (I have done this on the furnace in my house) the sensor in this unit is tucked into one of the heat exchangers and to get to it I would literally have to take the entire unit apart. Has anyone had similar problems like this with this model? FYI, I would consider calling a technician but the city of Mpls requires Master licenses to work in the city and Masters won't look at garage furnaces, at least the six companies that I called. HELP!!!!!
 
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Old 01-22-10, 02:34 PM
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Are the wires to the fan going to a control board or just to the relay that you mentioned? Have you tried to run juice staight to the fan?
 
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Old 01-22-10, 04:19 PM
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I can do a blog here explaining everything. (I have to go out soon to beat the freezing rain that is coming).A relatively easy way is to take the capacitor to a motor shop to have them test it. [If you do, shut off the furnace, and short across the terminals of the capacitor at where the 2 wires attach on the capacitor, as sometimes a potent charge is held!]. And if that is not it, then take the motor there. In my experiences, I do not get charged. They want you to think of them for when you ever DO need a motor.

On MY furnace motor that went to pot some months back, my wires rotted right down in where the wires go into the grommet entering the motor. So be careful by all that jiggling you are doing, without making sure you do not have a similar problem as me. If a bare wire hits the metal of the motor, the sparks will really fly. Mine did. When that happens unexpectedly, it can scare the you-know-what out of you.
 
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Old 01-25-10, 02:56 PM
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Thank you ecman51 for your reply! Brace yourself for some really ignorant questions . . . Where is the capacitor located and what does it look like? I read you loud and clear on the wire jiggling I will make note of this.
 
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Old 01-25-10, 03:03 PM
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Thank you too Pulpo for helping. I am at work right now and I can't check but if I remember correctly the black wire goes to the relay and the white wire is connected to the white wire for the exhaust fan. I have not run juice straight to the fan. If I understand what you are getting at, running juice to the fan would constantly cool the heat exchangers regardless if they are hot or cold, thereby allowing the furnace to come on and heat like it normally would only the fan would be on all the time. If this is what you are getting at, I have thought of it but I would like to just get it to run normal first. If that is not an option then I could try it that way. I know the fan works. It does run when I punch the furnace. However my knowledge is limited and as my name implies, I am just trying to save a buck!
 
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Old 01-25-10, 04:53 PM
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Only run the juice directly to the fan as a test to detetmine if the problem is in the fan itself or not. I didn't mean it to be a complete solution.
 
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Old 01-25-10, 05:12 PM
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Sounds like a loose fan wire connection somewhere, if rapping on it gets it to go. Check all connections. Pull connectors apart and reinsert.

Unless you are sending a big shock wave throughout the furnace and this is jarring some bad fan switch contact to make good connection.

Does your fan wire plug into say a Honeywell fan -limit switch located above the burners?, or to a thermodisc switch above the burners?, or does your fan wires go directly to a control board?
 
 

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