Monitor 21

[FordMan59]

I found a overhaul kit on ebay for $200 including the pot with the mat already glued in...also hayzee the empty light tells me something is still going wrong in the sump. got to regroup here and get this heater working...thanks a million...

Don't discard the old pot unless it's cracked or warped. It can be cleaned up and reused. There's also material available at McMaster-Carr's web site for mats and gaskets, Rutland 77 Stove Cement works fine for gluing the mat down. I recently bought a 1'X3' piece of silica material for burn mats and an 1/8"X16"X10' roll of high temperature fiberglass material for making gaskets, and a 2.7 oz tube of Rutland 77 Cement all for about $40. plus shipping.

[dfitz3390]

Fordman, how long is the MMC burner mat lasting ?

[FordMan59]

Fordman, how long is the MMC burner mat lasting ?

I don't know how long they will last but the material seems to be thicker than the original Monitor material and is closer woven. I just changed the burn mat in my 422 at the beginning of Feb. 2012 for the first time using the Mc-Master Carr material. The material and flame have been fine ever since. The silica material I bought was rated at 1800* F so I'm hoping it will last at least a few heating seasons. The piece I bought was 1'X3' (enough to make 27 burn mats for the 422) and was $9.54 if I recall correctly. The product number is 8799K3 and it's .026" thick. I think HayZee518 has also used material from McMaster Carr and may be able to tell you how long it's been lasting for him. The fiberglass material I bought for gaskets is product number 9323K21, it's 1/8"X16"X10' and is rated at 1200*F and is $26.10 per roll. The material isn't as thick as the original Monitor material, but it's strong enough it doesn't tear just because you look at it wrong. I figured if 1/8" wasn't thick enough for some applications I could just double up and make it 1/4" thick. The only gasket I had to replace when I rebuilt my burn pot was the gasket for the igniter. I did double the material just to be sure.

[HayZee518]

the woven silica material is coated with an acryllic just to give it stiffness. I'm sure uncoated would have worked just as well. silica [which is sand] is temperature rated for 1800 degrees. any hotter and it would melt into glass fibers. mine has lasted about six years and doesn't deform or curl up. as long as it isn't disturbed it should last longer. if you want to try a test, get a swatch of material, soak it with kero and light it. see how it is after the burn. see if it is still flexible or if it hardens.

[FordMan59]

the woven silica material is coated with an acryllic just to give it stiffness. I'm sure uncoated would have worked just as well. silica [which is sand] is temperature rated for 1800 degrees. any hotter and it would melt into glass fibers. mine has lasted about six years and doesn't deform or curl up. as long as it isn't disturbed it should last longer. if you want to try a test, get a swatch of material, soak it with kero and light it. see how it is after the burn. see if it is still flexible or if it hardens.

Thanks for that information. I too was wondering about how often I'd be looking at between mat changes using this material. Since you live in the Northeast and I live in KY where the heating season isn't as cold or as long maybe mine will last even longer. The original mat in my 422 lasted 16 years, but most of that time I was living about 35 miles out of Charlotte, NC where the temperatures seldom got below the twenties or thirties at night and during the daytime hours it was usually warm enough the heater didn't run or ran very little. Your heater probably runs at least twice as much and at higher flame than mine does even here in south central KY. Unless it's down into the low twenties or teens mine normally runs on low flame over 90% of the time when it does run and usually runs less than 50% of the time except on cold nights, then it's not uncommon for it to run nearly constantly, but it's heating about 1200 sf with ease. I think the material I bought was un-coated, because it's not stiff at all.