Is the filter clean?
What make /model furnace?
Is there a blinking light in the furnace?
I do not know if the filter is clean, it is a Lennox Pulse furnace and I cannot find a model number. I know my husband replaced the filter this past summer.
The number one reason for a furnace to do as you described is to run over temp....cool down...start again...over temp...cool down etc.
Before we go further I would strongly recommend checking the filter.
I cannot figure out where the filter is--can you tell me how to find it?
What floor of the home is the furnace on?
Attic, basement etc?
Thank you. Usually it is on side or the other at the bottom section. Here is a basic layout to look at. Here it is the left side bottom,
Okay, I changed the filter, although I didn't think the old one was that dirty. Do you think the filter is the problem?
I honestly do not know...I eliminate the items that pertain to that description.
The Lennox Pulse has a concealed spark plug and sensor so I will not be asking you to get too involved.
Another item is the drain off the furnace. This is a high efficiency furnace so it drains water. If the drains get backed up and stall water in the furnace, it can also fault operation. This involves seeing where the drain comes out and drains to...and seeing if it is clear. Sometimes involves removing drain line from furnace to check.