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Weil mclain boiler section replacement

rscheps
rscheps Member Posts: 4
in THE MAIN WALL
Are there any work instructions out there for replacement of an intermediate section in a well McClain CG hot water boiler? I replaced a cracked intermediate section in my boiler and all was happy and dry for 2 years. Then the joints started leaking. I used all new square cut o rings and the right high temp silicone on the flanges between all the sections and on the o rings. it only held for 2 years so I must have done something wrong. Tie rod torque Wrong perhaps? Silicone on O rings or not?. Any advice?

Comments

  • Fred
    Fred Member Posts: 8,542
    Are you sure the leak is at the joints? Once a section gives out on a boiler, other sections typically aren't far behind.
  • rscheps
    rscheps Member Posts: 4
    Not 100% sure it is the joints. But it is leaking from the side with the water channels and orings. When the section failed before it cracked right on the bottom closest to the burners. Maybe I should consider myself lucky that it gave me 2 more winters of service after the first cracked section
  • ChrisJ
    ChrisJ Member Posts: 16,315
    Why did it crack the first time? That's not normal.

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

  • HVACNUT
    HVACNUT Member Posts: 6,329
    How old is the CG? Is there still a block warranty? If not I dont know how many times I'd keep replacing sections. Seems a little redundant. Commercial boiler, ok. Residential, not so much.
  • rscheps
    rscheps Member Posts: 4
    25 yrs old, so way out of warranty. We had a leak in a baseboard overnight 2 yrs ago that may have drained the system and caused it to dry fire before we discovered the leak. There was no LWCO at the time.
  • Jamie Hall
    Jamie Hall Member Posts: 24,842
    It really shouldn't have needed any sealant. One hopes that the RTV didn't interfere with pulling the sections together enough to get the O-rings to do their job -- they can and will eventually leak if they aren't fully seated properly. However, what's done is done. As @Fred said, though, once one section cracks (or rusts through!) the others may not be far behind, an whatever stressed it enough to crack the one may well have created an incipient crack elsewhere which just took time to grow.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,470
    @rscheps

    download the boiler manual and follow the instructions. 25 years may not be worth the effort.
  • rscheps
    rscheps Member Posts: 4
    Thanks all

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