Furnace stays on for 2 minutes
I have a digital thermostat and my furnace seems to stay on for only 2 minutes at a time. It does this approximately every 10 min. The programmed cycle rate is 5/hr, so starting up every 10 min makes sense.
If the programmed temp is 72 F and the room temp is around 72 F, it will start up as usual, but only stay on for 2 minutes then shut off. The fan also works.
If I override the programmed temperature to 77 F, the furnace will stay on until the desired temperature is reached.
Is it normal for a furnace to start up and run for only 2 minutes if the programmed temp is close to the room temp?
Thanks.