Elastomer seals between sections of HW boiler

Joe Zimmer

It seems most manufacturers of HW heating system boilers (e.g. Burnham, HB Smith) use steel push nipples to make a tight seal joint between sections of their boilers. However, Weil-McLean uses elastomer seals. Of course, one of these seals is near the burners and will get reasonable hot (maybe 300 F or so, I am not sure), while the other is up high and will only get to the operating temperature of the boiler water, maybe 110 to 120 F. Also, most elastomers have chloride or fluoride constituents in their composition. What experience is there with this type of seal? How long term is the experience? How long has Weil McLean used elastomers? Which is better, steel push nipples or elastomers?

[Deleted User]

Here goes.

Saw my first elastomerics early 70's on an 86 Weil. Had some trouble, not from heat, but from deterioration caused (according to them) by oil from the combustion process.

They now include silicone to apply to the outer edge of the seals. The newer boilers also have a captured port for seal positioning. There were also problems w/ some of the more aggressive boiler treatment chemicals. Chemicals w/ petroleum content are verboten.

We have replaced many seals, & the section sealing rope, on 76, 86, & 88 boilers over the years. It is amazing how much more efficient the boiler is when it is reassembled after a complete fire & water side cleaning. A good cleaning, while disassembled, also seems to extend boiler life. We service some 86 boilers that are over 30 years old. A new jacket (88 fits 86) completes the package.

Weil is not the only company using seals, rather than push nipples. Smith uses a graphite compound seal on their 19A & 28 Boilers. I believe that is also true of the Peerless 28A copy. Peerless's 211A uses an elestomeric type seal.

The push nipple verses seal debate will rage forever. I know my guys would revolt if they had to do a push nipple boiler. I might join them.

Jed_2

Smith seals

Currently, Smith Boiler only offers graphite seals on the 28a series boilers!

RonWHC

I stand corrected.

The 19A Series uses an elastomeric seal.

Robert O'Connor_12

WM

Love the seals!
We have NEVER had a failure and lets just say we have more than a few installs out there.

Robert O'Connor/NJ

Joe Brix

the issue with nipples

is a requirement for well machined nipples and wells made to very tight tolerances. The use of lower quality cast iron and impurities in the casting can create a weak spot around a machined well where a leak has a bettr chance of forming. Sandwiching 2 sections together with a captured seal gives a little "fudge factor" in case the sections are not 100% perfect. Take a look at a Buderus or Viessmann and now the Burnham MPO (I hope), their castings are in a higher leage. I have never heard of a Buderus or Viessmann leaking. True, you won't find any that have been in this coutry for 30 years, but I hope the MPO and WM ultra Oil can obtain the same reputation.