Odd gable vent placement

[Jehannum]

I've finally closed on and moved into a new house with a great 3 car garage (yay!), and I'm getting ready to reassemble my workbench inside, but the place I want to put it has the oddest thing: what looks like a gable vent, installed at ground level.

I don't want to block an air intake. I'm reasonably sure though, that both the 85k BTU heater and 40k BTU water heater installed in the garage get their make up air from the 10" double wall flue that their combined chimney exits through the middle of. I haven't run the calculation (the garage is probably 30x24x8), but I think the room might be large enough not to qualify as an enclosed space wrt code compliance.

Is there any reason that anyone else could think of regarding why this odd vent might exist that would cause me to keep it unblocked?

I'll slap up some pics later.

 

[Jehannum]

Pic as promised:

(yeah, look at what Comcast's finest did with that FINE installation job... yeesh)

 

[James-W]

Can you take the vent off and see what it is for?

 

[Bondo]

Ayuh,.... Bein' so low to the floor, I'd guess it's to vent flammable fumes,.....

Gas fumes are heavier than air,...

 

[75gmck25]

My garage in San Antonio, TX had two vents at that level, and I think every garage in the neighborhood had them. The vents were installed when the house was built (for me), and I assumed they were there to let out some of the heat during the summer (100+ degrees for 1-2 months was typical). I never even asked the builder about them.

Bruce

 

[DC73]

I'm reasonably sure though, that both the 85k BTU heater and 40k BTU water heater installed in the garage get their make up air from the 10" double wall flue that their combined chimney exits through the middle of.

Is there any reason that anyone else could think of regarding why this odd vent might exist that would cause me to keep it unblocked?

Is the furnace and/or water heater mounted directly on the floor by any chance? Modern codes require furnaces and water heaters to be mounted off of the floor when in garages to avoid flammable vapors (as Bondo suggested). Maybe codes when this house was built allowed low wall ventilation instead? If this is your case, you might could plug the hole in the wall after raising the furnace and water heater.

Just speculating. Hope you get it figured out. Seems a waste to have a hole in the wall that may not be needed.

DC

 

[Zeke]

All garages are to have vents at the floor amounting to so many sq in per sq ft of floor and relatively evenly distributed or spaced. Gas burning appliances are to be 18" off the floor with a clothes dryer being the exception.

 

[DC73]

All garages are to have vents at the floor amounting to so many sq in per sq ft of floor and relatively evenly distributed or spaced.

That may be the case in NM where the OP lives but it's not a requirement in my part of Texas. I've never seen a garage vented as such until the OP posted his photo.

I would recommend the OP call the local building inspection department. They could advise him on what is required in Albuquerque.

DC

 

[Charles (in GA)]

I would recommend the OP call the local building inspection department. They could advise him on what is required in Albuquerque. DC

This was going to be my recommendation as I read thru the thread. Beat me to it.

Charles

 

[CNGsaves]

Guaranteed it's there for REASON . . . and according to code for the NG appliances in the garage. Leave it just like it is. Do NOT block it !!

I'd just make sure it has tight screen on backside so that critters can't get easy access to the garage - - ie mice, crickets, spiders, scorpions, etc !!

I'd work on fixing the dangling COAX line that your cable company did . . . re-route to central location and have all your indoor RG6 wires all come together to a high quality splitter (ie distribution box). The planning you do now will pay off with convenience forever.

 

[southalabama]

Around here fire ants would climb in with something that inviting.

Not typical of our local but someone out there will know. I doubt it was a what the hell moment by the builder

 

[JT-3]

Funny I clicked on this thread, I have that exact vent next to my water heater.

When I had a plumber come out last year to raise the heater and clean up the piping, he told me it was not needed anymore. The home is from the 60's and the heater/vent are in the corner of the garage.

I'm on the fence about covering, it lets in both cool and hot air.

 

[James-W]

Codes do change as time goes by. What the code was when the garage was built may not be the code today. I agree that it is best to check to see what the current code is before doing anything drastic.

 

[atfulldraw]

Funny I clicked on this thread, I have that exact vent next to my water heater.

When I had a plumber come out last year to raise the heater and clean up the piping, he told me it was not needed anymore. The home is from the 60's and the heater/vent are in the corner of the garage.

I'm on the fence about covering, it lets in both cool and hot air.

they called it a fresh air or combustible air vent for a gas burning appliance.....

it's so that the water heater doesn't burn all the oxygen out of the garage while you are working in there.

That would ****, oxygen being needed and all.

 

[Jehannum]

Is the furnace and/or water heater mounted directly on the floor by any chance? Modern codes require furnaces and water heaters to be mounted off of the floor when in garages to avoid flammable vapors (as Bondo suggested). Maybe codes when this house was built allowed low wall ventilation instead? If this is your case, you might could plug the hole in the wall after raising the furnace and water heater.

Just speculating. Hope you get it figured out. Seems a waste to have a hole in the wall that may not be needed.

DC

No, the furnace and water heater both have proper 24" standoffs from the floor.

We follow the national fuel gas code here, which would require low and high venting in what are termed "confined spaces", but the garage should support up to 130k BTU of combined gas burner before being considered a confined space, based on the 1:20 rule, and I'm below that now (and 88k BTU furnace + 38k BTU water heater ekes in just below that).

Based on some of the other stuff in the garage, I think there might have been a ceiling mounted heater unit that might have kicked it over, requiring low/high fresh air vent installation.

they called it a fresh air or combustible air vent for a gas burning appliance.....

it's so that the water heater doesn't burn all the oxygen out of the garage while you are working in there.

That would ****, oxygen being needed and all.

I'll probably keep the vent in place, since the water heater's on its way out, and I'll be putting in a tankless unit (those typically run much higher BTU ratings than tanked units; the one I installed in the house I'm trying to sell was 125k BTU, and was only a 4.3GPM unit).

 

[DC73]

No, the furnace and water heater both have proper 24" standoffs from the floor.

We follow the national fuel gas code here, which would require low and high venting in what are termed "confined spaces", . . .

Sounds like your furnace and water heater are out in the open in the garage. Here, they get put into closets and it is the closet that has to meet the high/low venting requirements and no other vents are required in the garage. They run metal duct from the closet into the attic for both the high and low vent.

If you wanted to get rid of the wall vent, maybe you could enclose your equipment in a closet with proper venting and then close up the wall.

Good luck with it. Now you've got me thinking I need to make a run to Albuquerque to get a Sadie's fix.

DC