I have a CCA24FCC that keeps shutting the furnace off for lack of air flow. The blower seems o be working well, i have replaced the filter even when it appears to be clean. Is there a sensor that measures the air flow that could be going bad?
Heating & Cooling - Filter
Answers & Comments
There are 2 blowers to be concerned with. The main blower simply passes the household air over the heat exchanger to provide warm air for the supply vents. The other blower, which is more important, is the draft inducer blower. This is a smaller blower that starts first to create a negative pressure in the fire box to ensure that carbon monoxide gases will pass up the flue when the gas jets ignite. There is a pressure switch associated with this blower. When the inducer blower starts, it pulls air up thru the flue until the pressure switch activates. Then the gas jets can ignite, warming the heat exchanger. A few seconds later, the main blower will start to warm the air. If the inducer blower or the pressure switch is faulty, the furnace will not fire up.
From what I read the inducer and pressure switch usually causes three blinks. When your furnace cycles, do the gas jets fire up? If so, the indicer blower and switch are okay. Four blinks is normally a high limit erro. It happens when the firebox semsor sees too much heat and shuts down the gas, even if there is still a call for heat. This is ususally due to either - 1. Bad main blower. 2. Clogged air filter. 3. Clogged heat exhanger. 4. Severely restricted ducting..