We have a Coleman gas furnace that is about 14 years old. The problem we are having is that the furnace is not kicking in all the time...it does not kick in about once every other day. Usually happens sometime during the night and when we wake up the house is cold.
The only way to get it to started again is to turn the power to the furnace on and off...and and then it will start again. We had a tune up done and the repair man cleaned the flame sensor and said the microchip reading is fine.
The repair man has been out a couple of times to try and determine the problem but because it only happens occasionally it is tough to diagnose.