Just put the flue.....right there

Love the 95% efficient furnace, hate the installer. Could have killed somebody…

Always amazing what we find.

Whats up with the cut-off/broken-off water line?

Maybe I’m not awake yet.

Please explain.

Me too…

The flue for the 95% furnace is powered and under positive pressure. The flue for the furnace is natural draft and uses air from the room to assist with proper draft. Because they are connected the positive pressure from the furnace will not let the DWH vent, thus spilling CO into the space.

This client called me to her house because she thought she had a mold problem because she and her kids had breathing issues. I told her to shut down the furnace and call an HVAC company stat.

Unless confirmed otherwise by a spill test at the water heater vent it may function fine.

I see your point but more info is needed IMHO.

Yes it does not look typical and that is when my spidey sense kicks in.

Wouldn’t this be prohibited? I write it up when cat 4 and natural draft vents have a common flue.

I didn’t say it was right just that it may function.

I would write it too.

The may help some.


I did not need to do a draft test to know that it was not working as designed. It is wrong and should never have been installed this way. The other concern now is going to be when the furnace and the water heater are separated thus “orphaning” the water heater.

Why would you spill test then? If the spill test passed it would still be an improper installation.

Juan, one of the purposes of this mb is to educate.

Posting look what I found stuff educates no one.

Just giving the OP a chance to share and help others.

The claim was made that it was spilling CO into the house. Maybe it was. I can’t tell from here.

I’m just asking a question. It seemed like you we’re saying a spill test would be needed before determining whether or not it was defective. I didn’t understand why.