This is a 96% efficient propane fired Goodman furnace installed by a reputable HVAC contractor in 2018. I’m in a cold climate, and exhaust gas condensation and ice forming on the vent termination are significant issues. I suspect this installation is in response to that issue. I don’t know if the HVAC contractor set up this second, parallel exhaust termination, or if the seller did it. Other than the unsupported pipe, I don’t recognize anything wrong with this, other than it is unusual. Am I missing something?
And since I have attention on this topic, is this configuration of the combustion air source acceptable? Unfortunately, I didn’t make note of the model or serial number on this unit this time, so I can’t look up the installation instructions. I see this air source configuration now and then, where the combustion air is sourced from the furnace room. This is not a very tight house, so I don’t see a combustion safety issue being present.
So, to confirm…it looks like the exhaust has been split into two discharges. That is not described by Goodman instructions and would be considered an improper installation. Not to mention, how does that solve icing? And the goofy discharges…The more that is exposed to outside temps, the better the chance of freezing.
You can do the math, if you want to, on the furnace room volume to see if it is adequate for the furnace (and water heater if applicable). I use a standard of 140,000 BTUs (100,000 BTUc for the furnace and 40,000 BTUs for the water heater) needs about a 40’ X 22’ X 8’ room for adequate combustion air.
Working through this inspection, I’m probably going to call the unsupported pipe, alert to the condensation issue over the door, alert to the furnace intake air port location, and recommend CO monitor in the furnace room for CYA. But →
The furnace room is adequately sized. There is an atmosphere vented water heater plus a dryer in the room. Adjacent connected room has a separate wood fired furnace. If I were testing for combustion safety, I’d perform a Combustion Appliance Zone Test, but that is outside the Scope of a HI.
Thanks for the input, surely not in the installation instructions. However, we inspect for function too. This is in response to a condensation issue (over the door). It functions… I did point out to the buyer that it was unusual. I’m not sure if I want to call it a combustion safety issue. Lack of support of the long pipe is an issue.
I can’t, but I right clicked on an image and the adjacent image could be enlarged.
It’s a PVC wye. The whole interior venting drains back to the furnace condensate collector and condensate pump. Yes, it surely doesn’t meet mfg instructions. I pointed that out.
ndegaris
(Neil DeGaris, CMI KY License # 102167)
7
Right click on a picture then select magnify image… Worked for me
I have no idea what they are trying to accomplish here, from what I can see, but as you noted, all piping must flow back to the furnace. The outside pipe does not do that.
I see this indoor combustion air arrangement fairly often in my area. I have looked up several model furnaces and have yet to find one that prohibits it. Most refer to it as a “Non-Direct Vent Installation Method.” Some of the requirements for the exhaust termination vary a little with this configuration.
That vent configuration makes no sense to me. I would write it up as an improper installation.
As for the air intake, I agree with Ryan, not problem, although I prefer to see them pulling air to feed the fire from outside as opposed to using the air that was just heated $$ to feed the fire, then get vented out.
