Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Water dribbling out of thermostatic traps

Options
Hello, and thanks in advance for any help you can offer to this completely outmatched homeowner. Fingers crossed that this is plain old user error :)

The Problem

I replaced all 18 thermostatic traps in my house with new cage units. There's no more clanging and banging, but there is water dribbling out of the (crossover?) trap covers.

History

My house has a two-pipe system. The boiler is a 30-year-old Weil-McLain. There are 11 radiators, each with a trap, and 7 additional traps in the basement. All traps were Cashin-Thermoflex 12s. The main vent is a Cashin-Thermoflex unit; it's hard to even see the top, let alone read the embossed text, but it appears to say something like "No. 301 Vent Trap".

I replaced all 18 traps with new Barnes & Jones 2896 cage units, along with new matching covers. I left the old removable seats in place.

The house also has radiant heat flooring in the kitchen, supplied by the same boiler used for the radiators.

Signs & Symptoms

6 of the 7 traps in the basement leak perceptibly, some more copiously than others. 1 radiator trap leaks perceptibly.

The pressure gauge near the Pressuretrol never reads above 0 PSI; in fact, if it budges from 0 at all, it's to go very slightly into vacuum.

The water level in the gauge glass changes when the system is under load. It gets slightly higher as the boiler is warming up, then drops lower after a while, returning slightly higher after things cool down.

While the heat is on, I can hear hissing from the vent every few seconds, and I can see the little ball on top bobbling around in its cage.

The return pipes never get much above room temperature.

Photos

Dribbling Traps



Gauge Glass

Boiler off

Boiler heating up

Boiler running

It's at this stage that the traps are dribbling noticeably.


Main Vent



Boiler



Radiant Heat Flooring & Misc. Other Equipment



Prior Art & Research

This thread suggests that leaking from trap covers may be due to:
  • Covers insufficiently tightened
  • Pressure in system too high
I've tightened the covers to the point that I'm afraid to tighten any further lest I strip the threads. Maybe I'm being too cautious? Only used a typical 3/8" hand socket wrench with a 1-1/2" socket to tighten them (and I had to use a breaker bar to get the old covers off!).

The Pressuretrol is set to cut in at 1/2 psi and cut out at 1-1/2 psi, if I am reading it correctly. As mentioned above, the pressure gauge near the Pressuretrol stays at 0 PSI, perhaps going just barely into vacuum while the system is under load.

The End

Thanks for reading this far :)

Please feel free at this point to regale me with my many boneheaded errors.

Happy to provide any additional information, photographs, etc.

Thanks again!

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 23,324
    Options
    No boneheaded errors -- except maybe one. Did you think to use any tape or pipe dope on the trap covers when you put them on? I have a notion -- which may be wrong -- that that type of cover seals on the threads...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    tomeon
  • tomeon
    tomeon Member Posts: 5
    edited November 2021
    Options
    Thank you for the quick response!

    The instructions from Barnes & Jones say:

    Apply graphite to cover threads [on the trap body].
    I wasn't able to find anything that billed itself as graphite sealant, so I ended up using Megaloc Multi-Purpose Thread Sealant.

    Should I try something else?
  • Jamie Hall
    Jamie Hall Member Posts: 23,324
    Options
    Megaloc should be OK. You may need to take up on them a little more...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    tomeon
  • mattmia2
    mattmia2 Member Posts: 9,670
    Options
    If it really is sealing on the threads or even on a metal-metal taper, an 8" or so 3/8" ratchet isn't much torque for threads that large a diameter. I wouldn't be afraid to use a bit of a cheater on it or a half inch ratchet. A few wraps of teflon tape in addition to the dope may seal a lot better if the threads are a little funky.
    tomeon
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,544
    edited November 2021
    Options
    I agree with @mattmia2 teflon tape and a small amount of dope (don't get any inside the trap) and a larger wrench.

    Worse comes to worse you could replace a couple of traps and see how that goes
    tomeon
  • tomeon
    tomeon Member Posts: 5
    Options
    Thanks, everyone — I tried teflon tape plus pipe dope on one of the leaking traps, and it seems to have fixed the issue. Will proceed to do the rest later tonight.
    mattmia2
  • retiredguy
    retiredguy Member Posts: 906
    Options
    Did you check the instructions for the replacement B&J cage units. On most of the ones I have replaced I had to remove the old trap seats.
    tomeon
  • tomeon
    tomeon Member Posts: 5
    Options

    Did you check the instructions for the replacement B&J cage units. On most of the ones I have replaced I had to remove the old trap seats.

    The instructions were a bit ambiguous on this point -- they say:

    The cage unit is a complete one piece trap renewal kit containing element, plug, and seat (emphasis mine)


    However, none of the half-dozen numbered installation steps in the document say anything like "remove the existing trap seat". Moreover, B&J 2896s are "seat in", which IIUC means that the existing seat should be retained.

    I ended up calling B&J technical support, and the representative I spoke to confirmed that the old seats need to stay in ¯\_(ツ)_/¯.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,544
    Options
    did you get the leaking to stop?
    tomeon
  • tomeon
    tomeon Member Posts: 5
    Options

    did you get the leaking to stop?

    Yes, I did -- thank you for asking. Most of the rest of the trap covers just needed a good torquing; the tape-plus-dope approach worked for the rest.