In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
customer had no heat on a very cold snowy night here in the northeast the other day, but it started working erratically, and was working when I got there the following morning. I checked and cleaned all the drain hoses and trap. I checked the gas pressure, pressure switch pressures, and did a combustion test on it, everything was fine. The combustion inlet pipe is kind of low to the ground and I think a snow drift might have temporarily blocked it causing the erratic heat operation. Inside the furnace it was wet, not on the bottom where the blower is, but up in the burner compartment in the front of the heat exchanger where the drain hoses come out of the secondary heat exchanger. Nothing was obviously leaking, no stains of water or anything, but the tray was wet and it was rusted like it has been wet before. Any ideas? Can't be the secondary heat exchanger or I would probably see water on the bottom? This is a Ruud 90% about 10 years old.