I have a approx. 6 year old Carrier 58STA110 natural gas furnace. The blower motor and circuit board was replaced last year. I have installed a new digital thermostat, and the problem is still happening. The filter is new. No return vents are blocked. There is no signal of an error on the furnace LED.

The heating system will call for heat and the system seems to respond appropriately. The blower comes on and heat is pumped into the house. After some time it seems that the whole system suddenly stops. The blower goes off and no gas is being burned. I can hear a small, what I believe sounds like a fan, running inside the unit. I am guessing that is the inducer. Within 30 seconds the gas kicks on and the system runs again. When the system is stopping, the temp in the house is below the target temp.

It seems that the some of the pauses last longer then 30 seconds during the middle of the night. It is very cold outside right now (sub-zero over night). The system is not able to get the temp inside close to the target over night. This has never been a problem before. It is set at 71, but have seen it drop to 64. This has been happening for weeks now, while outside temps were much higher.