# Furnace Intake Question



## crussell (Mar 12, 2018)

Friends of ours just bought their first house, and went there this week to check it out.

Was in the garage and found something very odd about the furnace. You'll see that the intake ducting has a large gap in it, and there appears to be old sealant where at one time if could/should have been connected, possibly with an older furnace.

Is this normal? I could see this maybe causing issues drawing in fumes/odors from the garage into the house. The house was obviously inspected, and I dont think this came up.


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## mowww (Jan 16, 2018)

@crussell that looks like a poorly installed plenum to trunk duct connection. Can you feel air moving into the void when the fan is running? I'd contact the inspector, something like that should not have been missed. They make canvas duct fitting connectors for $20-35 that should work, but somebody with sheet metal tools and experience should take care of it in case the anything needs to be deconstructed to get things properly installed.

It is possible, albeit remote, that in that gap there is a sealed component where no air is actually escaping/being brought in but if they can reach their fingers inside both sections, that's not the case.


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## crussell (Mar 12, 2018)

mowww said:


> @crussell that looks like a poorly installed plenum to trunk duct connection. Can you feel air moving into the void when the fan is running? I'd contact the inspector, something like that should not have been missed. They make canvas duct fitting connectors for $20-35 that should work, but somebody with sheet metal tools and experience should take care of it in case the anything needs to be deconstructed to get things properly installed.
> 
> It is possible, albeit remote, that in that gap there is a sealed component where no air is actually escaping/being brought in but if they can reach their fingers inside both sections, that's not the case.


I had thought the same thing, so I stood on the bollard and looked in but there was no internal connection. just a gap between the ducting. I'll be back down there this weekend to help them put in some flooring, and told them I'd look into it. I'm going to have them double check their inspection report.


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## g-man (Jun 15, 2017)

That's normally will be the outflow and not the intake. If it is the intake, then it could be make up air. Yes it is odd to grab make up air from a garage.


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## crussell (Mar 12, 2018)

g-man said:


> That's normally will be the outflow and not the intake. If it is the intake, then it could be make up air. Yes it is odd to grab make up air from a garage.


Typically, at least around here in Washington with forced air heating, the outflow ducting runs under the house to the floor vents and the make-up air comes from the top. My house is the same way, except I have an intake grate with filter in a hall way ceiling that draws the air from inside the house.


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## crussell (Mar 12, 2018)

Just got a text back from my HVAC buddy - So he said that the bigger concern here, is that if the garage is not vented, you are creating a negative pressure (vacuum) in the garage and potentially drawing fumes from the Hot Water Tank into the house... Long story short, he said a short term fix is to just seal it up with some foil tape, and long term is one day the furnace will need to be replaced. and the sheet metal can be fixed then.


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## Green (Dec 24, 2017)

crussell said:


> So he said that the bigger concern here, is that if the garage is not vented, you are creating a negative pressure (vacuum) in the garage and potentially drawing fumes from the Hot Water Tank into the house...


And possibly fumes from a car as well...some people close their garage doors immediately after shutting off their car inside the garage.


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## daniel3507 (Jul 31, 2018)

He needs to be contacting his inspector. They should have caught this and required the seller to pay for the fix


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## Bbq freakshow (Mar 9, 2019)

I do hvac i would just metal tape it and liquid mastic it for now. Should be good till system needs replaced.


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## crussell (Mar 12, 2018)

Bought a roll of metal tape to seal it up.

Reason it wasn't caught at inspection is because there was no inspection. The housing market here in WA is very competitive, and they waived inspection as part of their offer.

I feel like I'd still get an inspection done for peace of mind afterwards, but that's just me!


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## dicko1 (Oct 25, 2019)

Make sure that roll of tape is UL181 certified. It should say it somewhere on the roll and specs for flame resistance and adhesive lifetime so it wont dry out and fall off under heat and old age.


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## crussell (Mar 12, 2018)

Thanks - Looks like I got the right stuff :thumbup:


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## Overfloater (Jun 5, 2017)

crussell said:


> Bought a roll of metal tape to seal it up.
> 
> Reason it wasn't caught at inspection is because there was no inspection. The housing market here in WA is very competitive, and they waived inspection as part of their offer.
> 
> I feel like I'd still get an inspection done for peace of mind afterwards, but that's just me!


That's crazy. I would never wave an inspection. Even on a new house there can be expensive problems that should be caught by an inspector.

Housing markets are competitive everywhere. That is no reason to take that kind of risk. If the purchaser is OK with possibly footing a huge bill then that is their call but I would never do that.


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