A year ago, natural gas made it to my area. This year I’d like to have a service line run to my place.
In planning my conversion of the heating and water-heating plants from electric to natural gas, I am having difficulty finding any discussion or guidelines on the requirements for combustion air. I’ve discovered some general comments like “make sure you have adequate air for combustion” but that is hardly useful. It is obvious you don’t want them in the closet but how much “in the open” is enough?
And, please, before you answer, “Have the local professionals assist you.” ; well, there are no professionals in our area. Neighbor called for service on his water heater and the technician dumped a coffee can full of burner jets on the back of his flatbed and dug through them until he saw one that sparkled more than the others. My neighbor’s water heater burned yellow and deposited carbon like no tomorrow. He tried the other game in town and had no better luck. He finally went back to electric; poor soul.
Thanks for your assistance.
Replies
I have a 6" pipe coming from the outside to the floor beside the furnace. It is passive and ends at about 1 foot from the floor. This was code at the time the gas company installed my new furnace 5 years ago.
If at first you don't succeed...try again! After that quit! No sense being a dam fool about it! W.C.Fields
Taunton's "Code Check Plumbing" book might be a good thing to get -- it'll give you everything you need to know about water heaters.
First you have to determine if you have a confined or unconfined space. Unconfined is anything over 50 cubic feet per 1000 BTU/Hr, and you don't need any openings in that kind of space. If you have a confined space, you need two openings, one within 12" of the ceiling, and the other within 12" of the floor. If the openings are to unconfined inside space, they must each be at least 100 square inches. For horizontal ducts to the exterior, you need 1 sq. in per 2000 BTU. For vertical ducts, it's 1 sq. in. per 4000BTU. Direct openings need 1 sq. in. per 5000 BTU. And there's lots more in the book....
I'd suggest sizing your combustion air, gas lines, and vents not for the heater you actually use, but rather for the biggest heater you might eventually want to upgrade to. That way, you can change heaters without having to mess with the holes again.
-- J.S.
If you've selected the make and model number of the units; get the owners manual for them (May even have it as a pdf file off their website). The manufacurer usually sets out fresh air guidelines for confined and nonconfined spaces in their literature. Of course, they'll also have a caviate that you must also adhere to all applicable codes for your area... but it's a good start.
John's book suggestion is another good venue, and should complement the mfr's requirements.