While the furnace is in a long heat cycle (~30 minutes), I will hear the inducer motor cut off for 1 second and then it restarts and continues running. This 1 second shutdown of the inducer may happen 3 or 4 times during the 30 minute heat cycle. Only the inducer motor cuts off for this 1 second time period. The furnace blower continues running. Does the IDM need replacing or possibly the round manual Honeywell thermostat? 14 yo Tempstar Furnace.


The stat would have nothing to do with that. Do you have a variable speed inducer? Perhaps changing its speeds? If not then it should run the whole cycle because if it stops the pressure switch will open and shut the unit down and if that's the case for you be happy it's only a second or you wouldn't have heat. You may want to have it checked out before it's urgent.

Updated on January 12, 2018

Original Article:

How to Figure Out What is Wrong With Your Furnace
By Dan Robbins