I had a new 80% gas furnace installed which shared a common flue up thru the roof. the old furnace was naturally vented without a draft inducer. Now when the draft inducer kicks on there is a brief backdraft at the top of the water heater until the main burner fires, then it draws well. on the water heater there is a vertical pipe leading to a slowly angled up horizontal run to the main B stack. I wonder if increasing the angle or placing a small piece of sheet metal angled up where the water heater flue enters the B stack to prevent the inducer draft motor from blowing towards the water heater would help. Thank you for advice.
Brief backdraft at the water heater when when inducer motor starts until main burners ignite then fine
- Thread starter Maface
- Start date
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The furnace needs to tie in above the water heater flue. The furnace flue is fan assist and is creating positive pressure and causing a backdraft through the water heater flue. I would swap the connections so that the furnace is on top.
What G said
