Flue ?

[Lanny Freng]

I look at the roof and I see the flue vent for the water heater comes through... but there is what looks to be a PVC pipe up through the flue and through the flue cover. anyone ever seen anything like this? the water heater is draft exhaust, typical metal flue from the basement... I have no idea what the heck they have that PVC pipe up there. I couldnt go up there as the roof was covered with frost.

[Nick Ostrowski]

Lanny, I can't imagine for the life of me why somebody would do that but whatever their reason is, using metal and PVC together to vent the unit is wrong. Repairs by a professional are needed.

Assuming it is a gas water heater, is it by any chance a high efficiency water heater? You mentioned it is a draft exhaust. Does that mean the unit has an inducer fan that kicks on to assist in the drafting process? If the unit is a high efficency water heater, the entire flue pipe should be PVC because of the low temperature of the flue gases and the condensation that will build up in the flue. Any pics of the water heater in the house?

[Jerry Peck]

By any chance was a natural draft furnace replaced with a condensing type furnace and they simple re-used (er ... tried to ... re-use) the original vent and flashing?

[Lanny Freng]

No, the water heater was your standard AO Smith run of the mill non direct vent 3 or 4" draft exhaust water heater. I will right it up for repairs. There was some corrosion around the base of the flue which obviously is coming from rain running right down that PVC and into the metal flue.Thanks for the info.