Trane XV90 combustion air

[joebrisbin]

I am having a Trane XV90 TUY100R9V4W installed to replace an old gas furnace at my mother-in-laws house. The new furnace will be installed in an un-airconditioned laundry room at one end of the house.
My mother-in-law would like it if we don't have to cut a hole in the roof or wall for another pipe.

My question is, is it ok to take the combustion air from inside this room since the room is open to the outdoors by 2 wall vents.
The laundry room is about 9ft x 9ft, has two vent holes on an outside wall that are approximately 4 x 8 inches each with wire mesh and metal louvers (for cosmetics so they look good from outside). My guess is that this would make the air inside the laundry room to be at the same atmospheric pressure zone as the vent pipe.

This laundry room also has a gas water heater and electric clothes washer and dryer. The water heater has its own flue that is seperate from the heater flue.

Since there is approximately 64 sq inches of outside air, is it ok to take the combustion air from inside this room?

Would it reduce the effeciency to use this arrangement?

Thank you for your opinions, I really enjoy reading all the posts on this web site.

[mayguy]

SHould be ok doing that. only thing I wonder how much air will come in to the room, and make it too cold in the winter?

Where is the home at?

100,000 sounds like a lot of heat.. is the home large and old?

[joebrisbin]

The house is in Lafayette, CA. It is single story about 2200 sq ft, 50 years old with alot of windows (thin single pane) and no wall insullation.
The existing furnace is 135 intake / 108 output.
My in-laws like the heating of the existing furnace so I guess that the new one would be about the right size.
We have 6 quotes, and every one quoted 100k BTU. Some quoted 80% and some 90% and some both.

[berad]

softeners and detergents are not good for the heat exchanger. use a concentric kit. One hole will get your flue and intake outside. it's better for the unit, it will help you protect your investment.

[joebrisbin]

I am not familiar with a concentric kit. Does that mean having two PVC pipes going through one flue hole in the roof?

[BaldLoonie]

Never pull air from a laundry room. As berad said, the detergents, lint, etc are murder on the furnace, especially a condensing furnace. Concentrics are very nice looking, can be painted color of roof. I'll have to take a picture of one to show as an example.

[jeep6275]

to answer the question about combustion air. trane says they want 50 cubic ft of air per 1000 btu. for a confined space. once you do the math you will realize this is a lot of space. i wish i had an install manual but it also gives dimensions on louvers as far as size distance apart and location.
plus with the fresh air vent hooked up the furnace tends to be quieter if you have sealed combustion because you cannot hear the burners as well.
the coencentric vent package is the way to go.

[joebrisbin]

Thanks guys. I will ask my installer for a concentric kit.
The comments about do not use laundry room air make a lot of sense! We want this unit to last a long time.
THANKS FOR ALL THE ADVISE!!! We appreciate it.
JB

[t527ed]

Originally posted by berad
softeners and detergents are not good for the heat exchanger. use a concentric kit. One hole will get your flue and intake outside. it's better for the unit, it will help you protect your investment.

only way i would do it. heaters in laundry rooms are a P I T A.

[joebrisbin]

I searched the web for "concentric vent" and found a couple of different styles. One was a box that COMBINED both pipes into one common pipe (not a wise choice). The other looked good, one pipe inside a larger pipe with a Y connector. Here is a picture and a link to the full article.
Thank you all for your professional guidance!!!

http://www.hotwater.com/NewManuals/B...NTRIC_VENT.pdf

[jeep6275]

that coencentric is the one we use all the time. to the ho make sure the terminations for the flue are far enough away from the drier vent. venting outside and sucking lint back in isnt any better than no fresh air at all.

[joebrisbin]

Thanks Jeep,
I will make sure he puts the pipe in the existing roof vent hole instead of through the wall where the dryer vents.

Thanks for the inputs.
JB