Diagnose Rheem main pressure switch
Rheem 90RS furnace has been diagnosed with a bad Combustion Air Inlet. Tech is saying it is not creating enough vacum. Tech saying Combustion Air Inlet may have been fouled by "dirty gas", and will need to be replaced. The Tech says Rheem has a newer "field tested" Combustion Air Inlet which takes into account for "dirty gas". The number of flashes is 2 on LED blink codes which suggest the pressure switch is stuck open. My air intake is not blocked. This unit is only 1.5 years old. Could the Combustion Air Inlet be bad? Could something else be wrong?