furnace exhaust - http://www.hvacmechanic.com/ Forums

Original message

jmjrich

67.149.78.221

"furnace exhaust" , posted Sun 10 Feb 13:46

I recently replaced my gas hotwater tank with a tankless syatem. It is vented by itself now out the wall of my house. I capped the hole into the tee which also carries the exhaust for the furnace. Now I have condensation and it is leaking from the chimney into my basement. My furnace is a 90% and has a liner in the chinmey all the way to the top. Did I upset the warmair flow into the chimney by eliminating the water tank?

Replies:

answer

68.59.47.234

"Re(1):furnace exhaust" , posted Sun 10 Feb 14:50

Gee glad you aren't dead. The fan forced exaust from a 90% furnace is not to be connected to a passive flue appliance such as a water heater, it blows the carbon monaoxide out the water heater flue.
The 90% furnace will produce condensation but it should be caught in the PVC Flue and returned to the furnace. Is it leaking at the "cap off"? if yes...it was leaing into the water heater before...or the dry water heater gasses where evaperating what is now a leak. call a pro, not the 90% furnace installers, they are dangerously stupid.

Be good to your fellow man not nice there is a difference.

tom446

66.66.203.58

"Re(2):furnace exhaust" , posted Sun 10 Feb 15:16

Are you sure it's a 90 % furnace? A 90% furnace should not be vented into a chimney even by itself. In most cases they are vented through the side of the house or up through the roof with PVC. Hopefully you have the install manual that comes with the furnace which will tell you how the furnace should be vented. Follow the instructions in the manual.

If in doubt call a pro !