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?

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?

If the combustion air inlet was installed professionally why would it need to be replaced? If that is the case I would contact the company that did the install and make them fix it. This should not be a problem for a properly installed furnace.

The Tech says Rheem has a newer "field tested" Combustion Air Inlet which takes into account for "dirty gas".

The above just sounds like BS to me.

Is the company that is telling you this the same company that installed the furnace new? If that is the case then you are getting the run around.