Class B vent
Encountered something new. On a renovation, the natural gas to the water heater was turned off some months ago and the heater removed last week. The vent has dripped water, apparently in the morning, each day even in the absence of rain. Yes, I know that rain is not supposed to enter the vent. I suspect that moisture condenses in the cold vent and forms frost during the night. When the Sun hits and temperatures rise above freezing by 9am, the frost melts. This my speculation. Anyone seen this before? And what is the effect on a heater that is not operating during a vacancy in cold weather?