Venting 80% Furnace & Water Heater

Unregistered

Is there any problem with venting an 80% Trane 80XL furnace on the same vent as a water heater? Is Type-B piping required? The furnace is at the end of the vent. In this case, won't the exhaust from the furnace vent through the water heater (the furnace uses an inducer for venting).

hatchet

Off the top of my head - I'm pretty sure this is ok. I've seen this in many many new houses. I don't believe a B Vent is necessary unless there is no outside air for combustion air. Then again I think UBC requires outside combustion air anyway - one duct high and one duct low.

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Rich
WIT Construction Co.
Superior MT Contractor

Unregistered

Bjd

I know around here that the two cannot be inter connected, as one unit is power vented and could possible send exhaust fumes into the other unit in the event of a blocked condition.

They require the two to be exhausted to seprate flues.

Bernie

Unregistered

ohio new building has 80% and hw heaters connected to b vent. if it an old chimney..needs flue liner since 80% has alot of moisture to expel. also want fresh air ..

Unregistered

Along this topic.....I am buying a house that's been split into two apartments. One apartment has a new 80% furnace. The second apartment has an old gravity furnace that I am replacing with a 90% furnace. Both of the existing furnaces vent into the masonry chimney. I don't think that there is a condensation problem now since the gravity exhaust is so warm. However, when I install the 90% furnace, what is my best venting solution? Stainless Steel flue liner? Or can the 80% and 90% both go out a PVC vent?

Steve Wiggins

Induced combustion motor on a gas furnace pulls air through the heat exchanger and thats about it. It does not force air all the way out the flue pipe (or its not designed to anyway). So yes it is ok (according to code) to include the water heater in the same venting system but personally I wouldn't do it. When flue gasses get too cool they can condense on the inside of the flue pipe and cause this:

Bjd

Hey where is the cleanout on that, up here we cannot connect to the base like that we have to have a tee with a cleanout at the base.

Bernie