Thread: Furnace install question

Can anyone explain what the manufacturer is trying to say here? I thought wood was combustible.

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I think the lawyers had a hand in writing that one!

I think its the special "under the furnace only" wood. Its only available at the "special order" desk.

"A special combustable floor sub-base is required when installing on a combustable floor." Well if your going to burn the place down you want it eazy to light!

Poorly worded. The intent is not to install on soft base material such as carpeting but on a solid base first. Now, if that solid base happens to be combustible then it will need to be protected as prescribed by the mfr.
HTH

If it's ok with you Marc I'm going to hold on to that one.

Originally Posted by Eric Barker

If it's ok with you Marc I'm going to hold on to that one.

Its all yours buddy. If you want it in 4mb, I have that too.

BTW, here was the FAU.

I think that is saying that they know about the combustibility of wood, but that they don't know about the combustibility of the "carpeting" or of the "tile" (such as VAT or linoleum, etc.).

"Wood" they can handle because they probably tested it setting on wood.

Probably written by someone in a foreign country with a limited understanding of the English language.

Actually, the fire properties of various materials have been well documented. Most ANSI Stds and UL listings allow for a temperature rise of 90F above ambient regardless of the common material.

It's about the stability of the combustible material. A furnance can rock around when installed on soft material or if not installed on a continuous base. Most furnaces are installed on bricks or anti-vibration pads at the corners but most mfrs want a continuous base. In order to do this, you can use a sturdy sheet of plywood and put the pads or bricks under it.

Many freestanding gas stoves (the heating kind) are the same way. They can be installed on a wood floor, even when substantial clearances to wood must be maintained in other directions.

Considering the weight and stability of some stoves, it's hard for me to imagine that it's simply a matter of the surface being hard (I know, we're talking about a furnace, and not a stove here...but humor me). I can see why carpet would be a problem because of its combustibility and tendency to collect all kinds of crap in it. Maybe "tile" has too many unknowns?

here's what prompted me to look for the manual..

Originally Posted by Bob Harper

Actually, the fire properties of various materials have been well documented. Most ANSI Stds and UL listings allow for a temperature rise of 90F above ambient regardless of the common material.

Even back when that label was made? That label looks O-L-D ... like some of us.

Originally Posted by Jerry Peck

Even back when that label was made? That label looks O-L-D ... like some of us.

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HG will be joining us shortly he's in the OH.
....
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OEMs make special bases to allow the appliance to be installed on combustible flooring. It's an accessory

See page 11, figure 12

That's for installation of a downflow furnace, though - it goes through the flooring, rather than sitting on it. Or am I missing something?

Originally Posted by Kristi Silber

That's for installation of a downflow furnace, though - it goes through the flooring, rather than sitting on it. Or am I missing something?

Kristi, I believe you have it right!

Ah yes- I zipped past the picture with the insulation under the horizontally installed cabinet... Never mind...

I will go back to sleep now...

It's interesting seeing the install specs for furnaces, and how small some of the clearances are. Apparently some insurance companies like to see a minimum of 36" from combustibles in any direction.

Could be a Catch 22 written in some foreign language leagalspeak.