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Steam Radiator Bolt Torque

It seems over the last several years my one pipe steam radiators have slowly started making more and more noise, a loud pinging clanging noise, that got to the point that it was waking us up.

The system is one pipe steam, and the radiators are mostly sectional assemblies with either two or four stout rods that run the length of the radiator and are bolted in place. I've never tightened these so I went around the house and checked them all. A few weren't tight, a few were completely loose and this seems to have almost completely eliminated the noise problem. I torqued them down to 20ft-lb when cold, not too tight because I don't want to crack a section.

My question is, do you guys have a recommended torque for these? How often do you check them?


  • BobC
    BobC Member Posts: 5,479
    edited February 2019
    I'd think you would want to check the tightness when they are hot because if that number goes up by to much you might be on the crawly edge of having some unpleasant experiences.

    My system is just about 100 years old and I don't think they have ever been tightened. I just checked an 6 and a 8 section 38" tall radiator and the bolts seemed tight (rads had last seen steam about 90 minutes ago.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Jamie Hall
    Jamie Hall Member Posts: 23,442
    My practice on those tension rods doesn't involve torque. I make sure the threads are clean and very lightly lubricated, run the nuts on by hand to beyond where they will be when installed, install the rods, finger tighten the nuts and then a quarter turn with a wrench -- no more than that. All with the radiator cold.

    You won't crack a section. What can happen is that if the tension is too high when the radiator is cold, either the rod will snap or the threads strip -- more likely the latter.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England