Lennox G20 blowing cold air

Old 10-18-04, 10:33 PM
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Lennox G20 blowing cold air

I have the Lennox G20 Gas Heating and it is blowing cold air. I can see it igniting in the basement, but only cold air comes form the blower. It barely runs a miunte and shuts off? Any ideas?
Old 10-19-04, 05:05 PM
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if it is igniting, not just glowing, i assume the burners either do not completly light or soon go off?

if it is glowing but not lighting, sounds like gas valve is either not opening or gas **** is off
Old 10-20-04, 03:43 PM
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Arrow Another Possible Cause

Hello AtomBomb Welcome to the Heating Furnaces forum topic and the Do It Yourself Web Site.

If you can see burner flames but they shut off soon after igniting, may be the flame sensor is dirty or defective.

First turn off all electrical power to the heater and turn the thermostat to the off position or lower the temp to it's lowest possible temp.

Remove the sensor if needed. To clean it, use fine grit sand paper or steel wool. Clean the entire element to remove the rust, scale etc.

If the element has to be removed to perform this task, make note of how it is currently installed and how it is attached to the electronic module, etc prior to removal. Reinstall it exactly as it currently is. At this time also check the flamesensors electrical connection.

Both of these 2 steps, cleaning and checking the connections should or could correct the problem. If not, it's possible the sensor element is defective. Replacing, providing this part is in fact the cause of the problem, is the only solution.

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