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Air testing

Simply Rad
Simply Rad Member Posts: 165
Hello all
I have been performing an air test on all my systems the same way for years. Either slabs, gyp, Warmboard or rough-ins inspections I have always pressurized the system to 100 psi and then use a spray bottle of soapy water. Slab and gyp are easy to find leaks. For about 10 yrs now I have been using a direct return distribution system(shown in attachment) for my RFH systems, which adds fittings in the field. The other item that can be difficult to air test are the pre-manufactured zone manifolds(Caleffi twist flow), which have air eliminators incorporated in them. Most of time these system hold air, but sometimes like my current system they loose pressure at a slow rate. The current system has been on air test for over 2 weeks and has lost 10 psi(100 psi and now its 90 psi) I have sprayed all fittings multiple times but this is a very slow leak on a relatively large system. There is 9000' of PAP tubing and then add the distribution system. Any ideas or techniques to help this situation. Thanks in advance for you thoughts
Regards
Jeffrey Campbell
Jeffrey Campbell

Comments

  • hot_rod
    hot_rod Member Posts: 14,785
    Those two air vents have brass, hygroscopic caps on them. When you air test you need to use the two black plastic caps that are shipped along with the manifolds.

    The hygroscopic caps, as second level of protection, they only seal when they get wet.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Boon
  • "Don't sweat the small stuff."
    You've lost 10 psi in 2 weeks? Agreed, it's a large system, but I'm pretty confident that it will not leak at working pressure.
    Often wrong, never in doubt.
  • Simply Rad
    Simply Rad Member Posts: 165
    HR
    Hope you are doing well. I do use the black plastic test caps when air testing and spray them with suds. I poke a hole in the plastic bag and attach it to the manifold after I commission teh system. Still these manifolds can be challenging to completely seal and air test as they are designed for water. I use PAP fittings to make Ts for my distribution system and they can be tough to seal sometimes also. This is just part of our job but I am wondering if there is something to help find micro leaks with air instead of the blowing bubbles
    Jeffrey Campbell
  • hot_rod
    hot_rod Member Posts: 14,785



    All is well here, thanks.

    We test every manifold when they are assembled in Milwaukee. But not with pex on every branch.

    Are you having leaks with this fitting? With the dual o-rings and tapered insert, we have not heard of any issues. Make sure the tube is pushed all the way up onto the taper on that barb.

    Do you have one of the split end manifold nut wrenches to get a good snug torque? The PAP fitting with the brass ferrule takes a bit more grunt



    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
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