Lennox G40 no heat


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Old 12-16-10, 07:59 AM
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Lennox G40 no heat

Air inducer motor runs for maybe two seconds then stops. After 20 to 30 seconds furnace again tries to light but inducer motor will only run for two seconds. Any ideas?
 
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Old 12-16-10, 08:37 AM
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Generally speaking, the inducer motor should turn on and stay on as long as there is proper power supplied to the furnace and the thermostat is calling for heat.

Start by checking to verify that the thermostat is on. You can use a jumper wire between the R and W terminals on the furnace to bypass the thermostat. That ought to turn the furnace on and keep it on.
 
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Old 12-16-10, 10:31 PM
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After extensive trouble shooting and having the luxury of a second furnace, I think I found the problem. The ignitor has a very high resistance compared to my other furnace ignitor. Somehow the circuit board must sense that the ignitor is serviceable. If it is not the inducer motor immediately shuts down.
 
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Old 12-17-10, 01:08 AM
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Originally Posted by kknowles
Somehow the circuit board must sense that the ignitor is serviceable. If it is not the inducer motor immediately shuts down.

Nope. Try again.


Did you try connecting R and W together to see if the inducer motor stays on?
 
 

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