Cast Iron Boiler Section Sealing Methods

[Yeldud]

Some Cast Iron Boiler Mfr's (Burnham, Peerless, Others?) use metal push nipples to seal the water passages between adjacent boiler sections. They infer that this is a superior sealing method compared to other manufacturer's (Weil McClain, Smith Boiler, Others?) who use high temperature elastomer sealing gaskets. My understanding is that the differences are not significant with 180-200F hot water applications, but when generating low pressure steam in the 215-250F temperature range, the elastomer gaskets are much more prone to failure, and need to be replaced periodically, requiring boiler disassembly etc. I know that Smith Boiler has had problems in the past with gaskets, and have upgraded gasket systems, but I don't know how the upgraded gaskets have performed. Are there any cast iron sectional boiler opinons out there who can offer their experiences regarding reliability of elastomer gasket systems and metal push nipple sealing methods. Conjecture is okay, but actual experiences are even better. Thanks in advance.

 

[joken]

I have installed many Burnham water and low press steam boilers with nipples and never had a leak. Although I know nothing about the gasketed boilers I would choose to have one.. Ken

 

[chicopee]

I had to deal w/ boilers leaking at their elastomeric gasketed joints back in the 80's for an insurance company. It is about at that time when push nipples were replaced w/ elastomeric gaskets. I have been out of this business since the early 90's so I can not tell you what improvements were made in the composition of these elastomeric gaskets.
Back then leaking occured when the boilers were shut down for the summers and such leaks appeared to stop when heating resumed.
From recollection one of these boilers was comprised of over a dozen sections. It was unusually long for such boiler and every summer the leak would reappear.

Since such boilers were under warranty at the time, the manufacturers would take care of the leaking problem as it was very obvious of potential product liabilty claims.

I have to think that by now such situation have been resolved but from your inquiry it seems to persist.

 

[Yeldud]

From the above responses, it sounds like for some manufacturers, elastomeric gaskets gradually replaced the metal push nipple method. Is this correct? Did all manufacturer's try the elastomeric gasket approach, and did some stick with it and others return to the push nipple approach due to bad results? Or did some manufacturer's never use the elastomeric gasket approach? Of the domestic manufacturer's i'm most familiar with, 2 use push nipples, and 2 use gaskets... I'm trying to decide if one method is clearly superior to the other when used on low pressure steam, due to the leakage issue. I was told by one Rep (about 10 years ago) that the gasketed boiler in a low pressure steam application should be disassembled and regasketed every 10 years or so due to gasket deterioration. Is the same true with metal push nipples?