Boiler Clearance confusion

Patchogue Phil_2

I am a liitle confused about the clearances for my residential oil-fired boiler. Installation manual says to install <i>"as close to chimney inlet while maintaining acceptable clearances from all combustible materials"</i>.

The boiler is on cement slab in utility room back-to-back with fireplace inside the house. See picture below. I want to get the boiler as close as possible to the wall.

What is a "combustible material" in regards to the walls? Is drywall combustible material for this purpose? If NOT, what thickness of drywall, 5/8"?

Would cement board be better in my situation, allowing the boiler to be closer to the wall?

The installation manual for my boiler shows a diagram of clearance according to NFPA-31 + 89M (I do not have access to these documents). Manual shows 18" from stack, but only 6" from rear of boiler. The stack outlet from the boiler is only 3" from the boiler back. These seem to conradict each other. Are these dimensions for "combustables clearance" or for maintenance accessibility?

Can anyone please shed some light on this for me?

Thanks,
Phil

Dan Peel

Mfg. clearances

These are always fun to adhere to. The 18" reference is for unshielded vent materials to combustible wall surfaces. Shielded you can reduce by 50% (according to my fire insurance people) and by using a fire rated wall - check your local codes, but i'd opt for the cement board you can reduce your rear clearance to 6". Just had a very similar conversation this week at a jobsite over this Slant/Fin XL-30. Happy Thanksgiving CDN style.....DAn

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Mark Eatherton1

Draft hood maintenance clearance

is what I've been told. If you crowd the draft hood against a wall, it can influence the draft on the draft relief hood.

At least thats my understanding.

ME

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