York Diamond 90 no call for heat

Old 01-19-12, 08:30 AM
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York Diamond 90 no call for heat

I have a York Diamond 90, about 17 years old.
Problem I am having is: Heater will come on and bring the house to temp, then I see a continuous flashing LED (no call for hear) and the blower will remain on forever . If I increase the temp setting the heater will again light and bring up to temp. Blower again will remain on with flashing led (no call for heat)
Old 01-19-12, 09:47 AM
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I'd start by using a multimeter to check for 24 VAC at the R and W terminals on the furnace. The R terminal should have voltage all the time, and the W terminal will have voltage when the thermostat is calling for heat.

Find out if the thermostat is indeed calling for heat when it's turned up.
Old 01-19-12, 07:59 PM
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a slow flash may be normal for no call for heat. You may have your thermostat set to Fan ON instead of AUTO.

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