[Jchu2011]

Why my heating runs intermittently, rather than runs continuously until the set temperature has reached? Specifically, when temperature triggered, my heating only runs for about a minute and stops, and after 2-3 minutes it kicks on again and run for another minute and turns off. This on-off cycle goes on many time until the thermostat setting has reached. Normally, the heating should runs continuously until the set temperature has reached.

[cdad]

You need to have it checked by a professional. It sounds like you have a relay going bad. Have them come out and take a look. If it is a relay its not expensive to fix.

[SeattlePioneer]

Does the fan circulating air around the house turn on and stay on?


If so, the likely reason is that the air flow through the furnace which strips away the heat the furnace produces is impaired, causing the furnace to overheat. The limit switch then turns off the burners and the fan continues to run until the furnace cools off, at ehich point the burners turn on again and the cycle repeats.

The most common cause is a plugged furnace filter, followed by too many warm air vents closed, return air vents covered over, plugged air conditioning coil in the furnace, failing blower motor, damaged or dirty fan blades.

[Jchu2011]

Dear SeattlePioneer, it is the fan circulating air around the house does on-off cycle (1 minute on and 2-3 minutes off) as I was watching the air coming out the register. The burner does not stop until the temperature reaches the set point. Just the blower does this on-off cycle. I would not be surprised of this if the actual temperature is close to the setting. However this cycling happens even though the actual temperature is well below the setting. After the pre-set temperature has reached, this cycling would stop for long time until the room temperature drops to trigger the thermostat to start next cyling.