furnace - not blowing air

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  #1  
Old 10-15-04, 09:30 AM
isuras2
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luxaire furnace - not blowing air

My luxaire furnace doesn't blow any air. The A/C blows just fine, but when the thermostat is switched from "cool" to "heat", then the furnace igniter, heater, etc. turns on, but the fan to blow the hot air does NOT turn on. I have had the fan to the "auto" and "on" positions, but it doesn't help. Any suggesstions?

Thanks,
Isuras2
 

Last edited by isuras2; 10-15-04 at 09:31 AM. Reason: edit title
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Old 10-15-04, 10:17 AM
R
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If fan won't come on in "fan-only" mode, check the circuit breaker first. The blower fan is on its own circuit. If the breaker keeps tripping, there is a fault in the wiring or the fan motor. If the fan come on in "fan-only" but not in "auto", then I suspect the thermostat control.
 
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Old 10-15-04, 11:55 AM
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Hello: Isuras2

Thermostat not likely the problem cause. What is more likely is the automatic temperature sensing device which turns on the fan blower motor when the firebox heats up to a set temperature.

This part has many names. Can be called a relay, fan on/off switch/temp sensing switch, etc etc etc. Does not matter it's terminology. That furnace is likely to have one and it is not working as it should.

To locate it, be sure electrical power to furnace is off, however that is accomplished. Than follow the wires from the fan motor to the device. Once located, remove it and replace it. More than likely that device is defective. Replacing it is likely to solve the problem.

Some but not all, of these devices have a manual fan on switch. If it has that swtich or button and if it is connected, not as likely with the fan only on swtich on the thermostat, but if there is such a switch or button, while power is on, turn switch on or push the button.

If the fan motor turns on doing this, temp sensing switch not sensing firebox internal temp. Replace that entire part. If fan does not turn on, no power to sensing device or its not connected to manually turn fan on or defective.
 
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Old 11-06-04, 11:52 AM
jrobinson01
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Unhappy I'm having a similar problem

Hello,

I'm also having a problem with my furnace. After turning on the heater one day, I noticed that the fan wasn't blowing. I set the thermostat to fan "on", and the fan wouldn't come on as it usually does. So I went up to the attic where the furnace is to check for a diagnostic led flash per the manual. No flashing led, unit has power at the outlet it's plugged into. Manual recommends jumping the red wire to the green wire at the thermostat to check fan operation. No fan operation. What can I check next? I suspect maybe transformer is bad? Just a hunch, I don't want to start replacing parts without an idea the part is bad.

Any recommendations?

Thank you in advance.
 
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Old 11-06-04, 12:57 PM
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Wink

You sure you have power there at the plug? Then check out the transformer next for 24 Volts . like they said when you jumped R to G there at the tstat you should get the fan.
if transformer ok then it on down to the fan motor and check it out could be just the capacitor there.

ED
 
  #6  
Old 11-06-04, 07:51 PM
jrobinson01
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Smile Fixed it!

Found 24V at the transformer. Found blown fuse (3Amp). Replaced fuse and fan works now. I looked for a reason the fuse blew, but came up empty. I'll just have to wait and see....

Thank you.
 
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