Author Topic: Blower keeps running but burners shut off during call for heat  (Read 253 times)

Offline mir

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Blower fan keeps running but burners shut off during heat call between 3-4 mints of initial start up.
Replaced the filter which was fully blocked but problem is consistent. Any suggestion

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Re: Blower keeps running but burners shut off during call for heat
« Reply #1 on: March 13, 2017, 04:09:39 AM »
Do you see a LED light, on the furnace control board,  flashing a code?  Have you tried cleaning the flame sensor?

Offline mir

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Re: Blower keeps running but burners shut off during call for heat
« Reply #2 on: March 13, 2017, 11:17:09 AM »
Yes i have cleaned flame sensor. Burner come on for 4 mint when first start and than blower fan keeps running, thermostat in on auto. Can this be faulty limit switch?
Furnace model: c9mpd075f12c2
LED Code: 3 blinks

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Re: Blower keeps running but burners shut off during call for heat
« Reply #3 on: March 13, 2017, 01:14:10 PM »
It's a low pressure switch lockout code, according to the ICP C9MPD manual.

Check that your venting is clear and sloped properly, and check the P-trap and drain line are clear.

If those things checkout use a multi meter and manometer to verify if you might have a faulty control board or pressure switch.