Replies

1. 
   BillHartmann | Oct 02, 2006 10:23pm | #1

   The code is ZERO.

   Now other than that the code does require access to the front for servicing. And it does require that you need the manufactures specs.

   That is your real limitaion.

   Also a source of combustion air.

   http://www.codecheck.com/pg21_22mechanical.html#combustionair

   If you slip me a hat I can tell you where you can see the full chart (table m3).

1. FHB Editor
   JFink | Oct 02, 2006 10:28pm | #2

   so I can get as close as I want to the furnace, except the front for servicing, and for changing the filter, etc?

   Well, I won't get that close, but it is good to know I suppose. Looks like I may have to dig up that owners manual to see what the mfg. says about clearances too. Guh.

   Thanks Bill.Justin Fink - FHB Editorial

   Your Friendly Neighborhood Moderator

1. 
   rjw | Oct 02, 2006 10:38pm | #3

   What Bill said: In addition, the manufacturer's tags in the furnace often specify clearances.Consider the quality of workmanship in service and replacement if you make it too tough to get at it.

   Youth and Enthusiasm Are No Match

   For Age and Treachery

2. 
   Tim | Oct 02, 2006 11:27pm | #4

   Code, the International Mechanical Code 2003, that is,  specifically states "Forced-air furnaces shall be installed in accordance with the listings and the manufacturer's installation instructions".

   Which is, MOL, what the International Fuel Gas Code 2003 says as well. Depending on the specific make/model, the close sides (back and non-return side(s)) clearances are typically 1" for most gas/LP furnaces, maybe up to 2-4" for others, if its old or very low efficiency. If is oil fired, find the specifics (a good idea for any type). Again, as the other stated, combustion air and venting are more critical than clearances.

1. 
   Matt | Oct 03, 2006 04:35am | #5

   Right...

   But access to service panels is often 24" or more - again per manufacturer's specs,

1. 
   Tim | Oct 04, 2006 04:36pm | #9

   "..access to service panels is often 24" or more - again per manufacturer's specs"

   I didn't address service clearance on the front of the unit. Personally, I would have nothing less than 30" clear, 36" if possible. Via an open door is fine.

1. 
   rjw | Oct 04, 2006 05:00pm | #10

   I find that even just for looking at them, 36" is tight. I want my HVAC guy to be as comfortable as possible when working on my furnace.

   Youth and Enthusiasm Are No Match

   For Age and Treachery

3. 
   DonK | Oct 03, 2006 05:30am | #6

   How strange, this morning, I spent about three hours with a similar problem - the clearance between wood rafters/beams and the walls of the chimney off a propane fired HWH.

   Didn't have a current copy of the NYS Code handy, tried the computer for an hour of wasted time. Then tried the International - cause that I could find. Still no luck. Went to the library, and looked up the state code books, but it seemed to refer to maunufactures' specs. Back to the site, found the wet box in the trash, back on the computer, checked the website with no luck. Two calls to tech support and then somebody calls back and says 1" (which I don't have).

   I told myself I could just post the question here, but felt silly. After all, I should know this stuff, or at least how to get it, right? Thanks Justin. Next time I post first and ask questions later.

   Don K.

   EJG Homes     Renovations - New Construction - Rentals

1. FHB Editor
   JFink | Oct 03, 2006 05:37am | #7

   When it comes to asking questions on the forum, I try to leave my pride behind - I ask dumb questions constantly. I'm sure some people will look at me and think I'm in over my head, but the others know that it's the only way to learn.Justin Fink - FHB Editorial

   Your Friendly Neighborhood Moderator

2. 
   rjw | Oct 03, 2006 06:04am | #8

   1" for B Vent, 6" for single wall flue.

   Youth and Enthusiasm Are No Match

   For Age and Treachery

4. 
   CapnMac | Oct 04, 2006 05:55pm | #11

   Not much furnace experience (around here, that's just a heating coil on the end of the a/c blower used for 7-8 weeks a year <g>).

   Now, I do have experience with technology change versus construction/framing.  I try to always design in some "slop" in spacing around mechanical equipment.  Because that equipment rarely outlives a house, and the dimensions of the equipment always changes.  That 19 x 30 x 60 unit may be  24x24x40 in twenty years, or it could be 16x36x39, always an adventure futher on in the lifespan of a building. 

   I can tell you, from a tad too much experience, that discovering you need 3" more inches of clearance is tough enough; tougher with the hvac crew standing around.

   Technology can be subtle, too.  Just two weeks ago I got to learn how much fun it can be replacing rusted out 18"D x 55" tall WH with 19"D x 56" WH (that it is in a 'closet' 54" AFF even less help <sigh>).  Huzzah for the sawzall, is all I can say.

   Occupational hazard of my occupation not being around (sorry Bubba)
1. 
   wane | Oct 04, 2006 07:04pm | #12

   I think you'll find that duct work off the main vertical trunk(front, back, sides) dictates placement of the furnace more than clearances, most transitions are typically 18" long ..