Well what I mean by a good cleaning is I took the doors off for the chambers cleaned everything thoroughly then I just took the distribution blower apart gave it an excellent cleaning of which it really needed,that you pointed out to me in the previous posts. Now I'm trying to locate the air switch and I'm looking at the manual but I can't make out the corresponding numbers to the list of parts on the diagram to find the location. ThanksThe vacuum switch(air) is the only thing in the back that has a rubber(silicone) hose going to it. Low/restricted air flow can also cause the error.Not sure what you call a good cleaning,checking intake and exhaust for obstructions(mice and birds), removing combustion blower and cleaning the passageways inside,removing the 2 heat exchanger covers and cleaning inside that chamber/passageways.