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Pressure Test & Isolating Runtal Radiators

OaklandNSOaklandNS Member Posts: 28
I am wondering if anyone here has experience pressure testing a system and isolating Runtal radiators. My system is installed and operating, with a caleffi manifold and 1/2" Fostapex homeruns to each radiator. The radiators have Runtal (Oventrop) thermostatic valves on supply and lock shields on the returns.

When I did a test yesterday, around 50 PSI seemed to open up the closed thermostatic valves and introduce pressure to the radiators (which shouldn't get more than 50-60 PSI) (I could hear them start pinging). Runtal confirmed that the valves will start to lift open at about that pressure and suggested using the plastic shipping caps that come with the valves to hold the pin down and close them off. Oventrop said that might work, but 100 PSI might pop those, too.

Have folks had success with with isolating the Runtal valves under similar circumstances? I'm thinking I might be able to rig something up with a metal nut/cap on the thermostatic valves to hold them closed, but they are threaded M30x1.5 which isn't an easy thing to find. I'm not really worried about leaks---the system held 50 PSI just fine for a few hours with all the valves open. It's just a matter of appeasing the inspector at this point---maybe he'd let me get away with a 50PSI test if I show him the limits on the radiators, but I don't know. I don't really understand why the code requires 100PSI on a system with an operating pressure of 12--20PSI.

Thanks in advance.


  • kcoppkcopp Member Posts: 3,236
    Where is this that they require you to do a pressure test on heating?
    And why so high?
    I would never test more than 30psi... you will do more harm than good.
  • OaklandNSOaklandNS Member Posts: 28
    Oakland, CA. I know, it's driving me nuts. California Mechanical Code section 1205.2 says the following, which I think means just the piping, but not the emitters or boilers.

    System piping and components shall be tested with a pressure of not less than one and one-half times the operating pressure but not less than 100 psi (689 kPa). Piping shall be tested with water or air except that plastic pipe shall not be tested with air. Test pressures shall be held for a period of not less than 30 minutes with no perceptible drop in pressure. These tests shall be made in the presence of the Authority Having Jurisdiction.
  • Alan (California Radiant) ForbesAlan (California Radiant) Forbes Member Posts: 1,554
    edited January 3
    Did the inspector tell you he wants the system pressurized that high or are you just going by the book. I've never heard of that on a radiator system. They typically want that kind of test on PEX tubing before the concrete pour.

    I'd wing it - call the inspector and see what he says.

    Alan Forbes
    Often wrong, never in doubt.
  • OaklandNSOaklandNS Member Posts: 28
    Alan---great to hear from someone local, thank you. An inspector told me on the phone he'd want 100 PSI, but he didn't see the system and maybe assumed it was a concrete pour. He's also not the usual inspector---he was on duty over the holidays.

    I am thinking I will get everything else ready and try to prevail on the normal inspector's goodwill and common sense with a 50PSI test. If that doesn't work, I suppose I'll deal with it then.
  • I wouldn't even mention a pressure test to the inspector, even though you have the system charged. Let him do the talking.

    If you did a good job installing the radiators, he'll be impressed that you are so skilled and will sign the job card.
    Often wrong, never in doubt.
  • OaklandNSOaklandNS Member Posts: 28
    Well, fingers crossed on the quality of the installation of the radiators, then. :smile:
  • OaklandNSOaklandNS Member Posts: 28
    Bummer. The inspector needs 100 PSI test of the pex tubing. He said it was dumb, and they have had conversations in the office about accepting lower tests, but can't for now. He even called his supervisor. He said I jumped the gun, and normally people will do the pex, cap it, get the test done, and then install the radiators. He mentioned the DIY learning curve :smile:

    I guess I have two options--- cut the pex lines to each radiator, loop them for the test, and then reconnect. Or find a cap that will hold a Runtal (oventrop) thermostatic valve closed at 100 PSI so I can isolate the radiators for the test.
  • OaklandNSOaklandNS Member Posts: 28
    In case anyone comes across this thread, the manufacturer of the thermostatic valves (Oventrop) makes a manual cap that can hold up to 145psi. Oventrop part no. 1012565.
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