On Sat, 27 Nov 2010 21:22:04 -0500, aemeijers wrote:

On 11/27/2010 8:38 PM, zzzzzzzzzz wrote:
On Sat, 27 Nov 2010 19:19:01 -0600, wrote:

HeyBub wrote:
Ed Pawlowski wrote:
wrote
1) I'm getting a new oil furnace in the basement, and the installer
wants to put a brick under each corner. ?? Is this something old-
timers do? Is it a good idea?

Are the bricks to prevent rusting? There has been water in the
basement on several occasions but it only made it to the furnace
when the furnace itself was leaking,

If you had water before, you'll have water again. Maybe next week or
next year or next decade. The bricks buy you a few inches of time.
The also promote good air circulation around it to prevent rusting.
In some cases, it makes it higher, thus easier to service.

But a "few" inches means a LOT of safety. Assume 1,800 sq ft of
basement and 6" of support. That's 900 cubic feet of water before the
flood hits the furnace gunwales. That 900 cubic feet is almost 7,000
gallons!
Usual faucet flow is in the neighborhood of 0.5 gallons/minute. For
the above calculations, an open faucet in the basement would take
14,000 minutes (or almost ten days) before the water level reached
the furnace.

As some have pointed out, some faucets act like fireplugs with an output of
65 gallons/minute. If you live in one of these homes, the 7,000 gallon level
would be reached in about an hour and a half.

The point is, however, leaving the furnace on the floor would subject it to
ruinous 1/4" of water in the original calculation in a bit less than ten
hours. Living in the water-hell home, the critical level would be reached in
a mere four minutes.

Bottom line: Depending on your water pressure and delivery pipe, by putting
the furnace six inches above the floor, you have between 90 minutes and ten
days to recognize the problem. If the furnace is left on the floor, you've
got between four and 90 minutes to sober up.

All that aside, a concrete floor can sometimes act as a wick to elevate
ground water to its surface.

I think that's the key. If the furnace is put directly on the concrete floor
it could be constantly damp. Cement blocks are cheap, and don't burn well.

Some sort of spacers would make sense. I would use something made out of
concrete rather than a brick made of clay, though. Sometimes those turn
to dust at inconvenient times. I wish the people who installed my
furnace had put it up on blocks. No flooding issues (knock on wood), but
that filter housing is a knuckle buster right next to floor. A couple of
inches up would have made it easier.

In my previous house the furnace (boiler) was on 4" solid concrete blocks. The
filter was on the tank. ?? I never worked on it, so don't remember too many
details.