Diagnosed weak pressure switch It is rated 0.65"wc, actual pressure across it was 1.1" Tapping on it would get it to close Got a universal pressure switch from truck stock Set it up for 0.65"wc closing pressure, it opens at 0.61"wc Verified numerous times the new pressure switch closes exactly at 0.65", won't close at 0.64" Moved factory port restrictors to the new switch Installed new pressure switch into the furnace Cycled furnace numerous times Furnace is operating normally at this time. Pan under the furnace is holding water, but everything inside and around the furnace is dry Filter shows no signs of water damage Saddle valve for the humidifier was leaking. Shut the water off to it Leak appears to have stopped