Ok, so now it’s dumping carbon monoxide right outside the rear basement wall. Doesn’t that become a health issue?
So does many gas-fired direct vent fireplaces. What do you think is the next consideration?
Hey Brian, good point. Would it matter the BTUs involved? I think most fireplaces you described run about 50-60k BTU while the furnace is at 90k BTU. Would this have any effect on the amount of carbon monoxide? This is all well outside my pay grade at the moment so I’m on a learning mission here.
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Manufacturer first. If they do not offer explicit instructions, here is another source.
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BTU output has little to do with CO produced by the appliance (furnace, water heater, etc). CO is a result of inefficient combustion, be it 60k or 90k BTU. CO level of a combustion appliance is tested at a location where it is undiluted. For a draft hood appliance or any appliance, on the combustion side of the draft hood. The limit is 25ppm CO, no matter the BTU output. Above that level, service (cleaning) is recommended.
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Got it. Thanks Michael!
GMS809048
For a Goodman gas furnace with a wall vent, ensure the vent terminal is at least 1 foot from windows and doors, 3 feet from inside wall corners, and 1 foot above the ground and snow level, while also avoiding cold floors, decks, or roof overhangs.
Look good from here.
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Anthony, the white substance in the photo may indicate incomplete combustion. The photo is inconclusive.
White Residue on Combustion Vents – InterNACHI Inspection Narrative Library.
A good short read…
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Hey Brian, I thought that too, initially, but the black refrigerant lines sit directly between the vent pipe and the white deposit on the furnace and they were clean.
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That would be correct information if the furnace that is being discussed was a 92% efficient furnace.
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@aponder , what you have is an incorrect vent installation for that type of furnace. Many might try to argue the nuances, blah, blah, blah, but whenever you come across a Cat 1 furnace using B-vent in a residential application, you can be 99.99% sure that it should be terminated vertically and above the roof line. A commercial application may have a little more “leeway.”
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What you have is not acceptable. The Cat l furnace you are showing must be vented vertically. To vent horizontally at the sidewall it must have a fan assisted (power) vent.
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Are you sure about that? My criteria is that an atmosphere vented appliance must be vented above the roof line. This will have a draft hood at the appliance (furnace, water heater, etc). A draft assisted appliance, like a power vented unit, can be drafted out the wall.
There is no picture of the interior of this furnace, but it appears to not have a condensate drain, meaning lower efficiency and higher flue gas temperature. The B vent confirms that, if it’s the proper vent material for this model.
It also has open louvers and an open port on the furnace housing. There is no visible draft hood. I can’t tell if it is atmosphere vented or draft fan assisted. If it has a draft fan, I’d be happy with the out the wall venting using PVC pipe. If no draft fan was present, I’d call it for not venting above the roof.
I don’t recall seeing a draft assist appliance vented through B vent, but my memory might be off. I’m not positive that a draft fan assisted appliance can be utilized with B vent. The seal at the couplers and elbows might be prone to leakage under positive pressure, thus being a CO hazard.
That’s my take at my level of understanding, without further research.
And have a sealed vent system like PVC (and there are a few other acceptable vent materials that are sealed and have gaskets, but are very expensive).
Pretty sure. But we could use an HVAC expert in this group for sure.
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The code in my state says it is above the roof line for B-vents. This is a Cat 1 furnace with a B-vent.
The manufacturer describes this:
Category I Venting is venting at a non-positive pressure. A furnace vented as Category I is considered a fan-assisted appliance and the vent system does not have to be gas tight. NOTE: Single stage gas furnaces with induced draft blowers draw products of combustion through a heat exchanger allowing, in some instances, common venting with natural draft appliances (i.e. water heaters). All installations must be vented in accordance with National Fuel Gas Code NFPA 54/ANSI Z223.1 - latest edition. In Canada, the furnaces must be vented in accordance with the National Standard of Canada, CAN/CSA B149.1 and CAN/CSA B149.2 - latest editions and amendments.
I think we are saying the same thing and we both agree, except I’ll up it to 100% sure. The thing that puzzles me is, where is the draft hood? Is it inside the furnace enclosure instead of on top?