- My Ducane MPGA100B4B furnace is shortcycling (2 minutes from fan on to fan off)
- The thermostat's Heat Anticipator setting doesn't seem to matter for the on-time, maybe the offtime changes
- The thermostat is of the round mechanical variety, not digital
- The furnace's control board seems to be blinking healthy codes - steady blink when off, faster steady blink when on.
- The air filter on the bottom left side of the unit doesn't seem too dirty.
- If I turn the thermostat to below-temp for a few seconds and then back above temp, the furnace will turn on again immediately for its 2 minutes.
- It's cold in here!
What might it be? What can I check?