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Hi,
I just bought a house with an Intertherm CMF2 80 PO CONV. I fired it up for the first time today, and the fan doesn't turn on automatically when the furnace is heating. The fan will run when the switch is on. How hot does the furnace need to get before the fan is supposed to come on? I tried letting it get hot enough that the flue was too hot to touch, but the fan still didn't kick on.

Edit: Some, but not all, of Nordyne's installation and parts manuals for this model mention a fan limit control, kind of a dial with settings to turn the fan on and off. My furnace doesn't seem to have this, unless it's hidden deep inside. Should it have one? All I can find are the main limit switch and the fan limit switch. It's quite possible that furnace parts were removed by the idiots who tried remodeling the house before I bought it.

I can give you some things to test, are you any good with a multi-tester/multi-meter?

I can use a multimeter, yes.

Okay, pull the panel off to be able to test the fan and limit switches. The fan switch usually has orange wires going to it. When the T-stat is calling for heat and the burner has been on for about a minute the fan switch will close and send power to the blower motor. Set the tester to AC volts and read the supply side of the fan switch, should have voltage there. After it "clicks" you should have voltage through that switch to the blower. If it clicks and sends NO power, replace it. If it doesn't click and the furnace ultimately goes out on limit, replace the fan switch. It should have come on and didn't.

You can also kill power to the furnace, pull the wires off the fan switch and jump them together. Restore power,turn the T-stat on for heat, the blower should come on right away. If that's the case I'd say your fan switch is bad and should be replaced.

Thank you for the help! It looks like the switch is bad, so I've ordered a new one.