intertherm m1mc 056a bw put to "on" now blower is on but col

[punky729]

Help! Woke up cold. Furnace will ignite, but shut off before blower runs. Instructed to change from "auto" to "on" on thermostat. I did that now when set at 50 degrees blower comes on fine, when set at 60 degrees, blower shuts off.

[Robert]

With t-stat set to on instead of auto, blower should be running continuously.

If burner is shutting off before blower comes on, may be a bad flame sensor or ignitor which serves as flame sensor.


Thanks,
Robert