I have been receiving several (40+/-) reports of a white, flakey deposit that forms and blocks the hose connection at the IDM blower housing.
These are Rheem/Ruud units, 90+ direct vent installations. I'm thinking there is a connection to the cold combustion air from the outside.
Some of these "problem" units are re-occurring most every year. The tech simply takes a small screwdriver and opens the hose connection.
I don't know at this time what number of units are natural or LP.
Any thoughts or help would be greatly appreciated...