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Sealing combustion test holes on pvc

Paul_69
Paul_69 Member Posts: 251
in Gas Heating
what are options for properly sealing combustion test holes on high eff.boilers/furnaces after taking tests in the pvc venting. Seems like most boilers have provisions built in but some do not and condensing furnaces almost never do.

Comments

  • Robert O'Brien
    Robert O'Brien Member Posts: 3,568
    Brass plug will self tap
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    Paul S_3
  • Steve Minnich
    Steve Minnich Member Posts: 2,868
    Before I started using test port tees, I would drill and tap 1/2" holes and then plug them with brass or stainless tapered plugs.
    Steve Minnich
    New England SteamWorks
  • ratio
    ratio Member Posts: 3,922
    Any thoughts about plastic threaded plugs?
  • hot_rod
    hot_rod Member Posts: 24,555
    ratio said:

    Any thoughts about plastic threaded plugs?

    You may need to run a tap in before a plastic plug would thread in.

    I've put a stainless steel hose clamp around the hole. The clamp off a 3" no-hub band works well. Maybe note "test port" with a black sharpie for the next tech.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Paul_69
    Paul_69 Member Posts: 251
    Brass plug will self tap tight enough to seal good?
    Thx
  • delta T
    delta T Member Posts: 884
    I prefer stainless plugs, I've seen too many brass plugs rot away from the condensate.
  • Tim McElwain
    Tim McElwain Member Posts: 4,651
    Stainless steel is best!
  • Paul_69
    Paul_69 Member Posts: 251
    Thx Tim. U need to drill and tsp pvc or will the plug thread in itself
  • Tim McElwain
    Tim McElwain Member Posts: 4,651
    I pre drill the hole and then use the stainless steel bolt to tap the PVC.
  • Paul_69
    Paul_69 Member Posts: 251
    Thx for clearing that up Tim. I think this is the best way. Taking reading of co outside at termination is not as accurate?? What size bolt 1/8?
  • Tim McElwain
    Tim McElwain Member Posts: 4,651
    I use 1/2" as it is easier to work with. I also use a little RTV sealant on the threads.
  • Henry
    Henry Member Posts: 998
    Brass plugs will rot through within 2 years. 3/8 plastic threaded plugs with some pipe dope work.
  • Henry
    Henry Member Posts: 998
    Brass plugs will rot through within 2 years. 3/8 plastic threaded plugs with some pipe dope work.

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