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I can't get the leaky relief valve to come off the boiler - what do I do

chuckworkbchuckworkb Member Posts: 5
I have a leaky relief valve on my boiler, and I can't get that darn thing off. I don't have a lot of room to get in there with a wrench because it is so close to the return line which is right next to it, but I mean I gave it everything I have and I can't get that thing off. They didn't use teflon tape when they put it in, it has some other kind of pipe thread sealer on it that is black, and like a rock. The valve is connected to a 5 inch nipple, which is connected to a 90 Elbow into the top side of the boiler. That nipple also has the same black pipe thread stuff on it. I don't want to put a 24 inch pipe wrench on it and crank on it and bend or break the boiler, ( it's steel not cast iron)

What can I do?



  • Jean-David BeyerJean-David Beyer Member Posts: 2,530
    I am not a plumber.

    but I read a lot. Can you use two 24 inch wrenches? One on the thing you are trying to remove, and one below it to protect the boiler underneath? On my boiler they do not specify wrench size, but they recommend two wrenches to protect things.
  • chuckworkbchuckworkb Member Posts: 5
    using wrenches on that valve

    The problem is the return line and circulator pump are literally right next to the valve, like an inch away, so I can't get a pipe wrench on that 5 inch nipple, ot hold it and counteract the force of trying to get the valve off.

  • Jean-David BeyerJean-David Beyer Member Posts: 2,530
    Can you saw it off?

    That might give you more room. Of course, once you do that, you are totally committed to finishing the job. 8-(
  • JackJack Member Posts: 936
    You are totally committed

    all ready. Shut off and drain the system. Put a torch to the fitting holding the RV. That should soften, loosen, expand the fitting holding the relief valve in place allowing you to "do what is necessary" to back it out. Your other alternative if that doesn't work is to cut the main and section it back in giving you the needed access. Maybe you can get in there with a smaller pipe wrench and a cheater.

    I guess your situation is why we build them so we can service them! Good luck!
  • chuckworkbchuckworkb Member Posts: 5
    cutting the pipe

    So, are you saying saw off the valve above the threads, and then try to chisel it off. Ugh!

    How about this - cut off the pipe, below the threads, then use one of those shark bite couplers, to a pipe thread and then thread the relief value on there?
  • chuckworkbchuckworkb Member Posts: 5
    I just found out sharkbite couplers won't work on black pipe

    My idea to use a Sharkbite adapter won't work since Sharkbite adapters only work on Copper. PVC, or that PEX tubing.
  • SlimpickinsSlimpickins Member Posts: 314
    Call a pro

    There is always a way to do something, they got the relief valve on there didn't they? Call a pro to do the job, we have lots of years of experience and lots of tricks of the trade. Just because the relief valve is leaking doesn't mean it's bad, it might just be doing its job and you have other problems that a pro can diagnose. 
  • chuckworkbchuckworkb Member Posts: 5
    relief valve

    The pressure in the boiler is not over 17 lbs at the hottest temp, so there is no issue with over pressure. I have confirmed that with two pressure sensors, since I really don't trust the one that came with the boiler. There is a new expansion tank, , and a new water inlet regulator, and back flow preventer  in the system.

    Of course the valve went on, ( ten years ago) so it will come off somehow. I was just hoping for some ideas on how to get this off, since the installers used some super strong pipe thread sealer on the threads, that has hardened like a rock over time.
  • Jean-David BeyerJean-David Beyer Member Posts: 2,530
    they got the relief valve on there didn't they?

    They got the relief valve onto my new boiler, too. And they used both Teflon tape and pipe dope. So I might have unscrewed easily. The valve is not leaking, but when I got a new contractor, I asked them to remove the valve and re-pipe it because after they put the valve in, they put a horizontal piece in, an elbow, and the long pipe to near the floor. The geometry was such that there were two problems. 1.) you would not be able to tell if the valve were leaking because the overflow came out in the narrow gap between the boiler and the wall. 2.) If you wanted to replace the valve, you would have to cut out the elbow and the long piece. So I had the new contractor do it over. Now those things unscrew, and they have Teflon tape and no dope after the relief valve, where there should be no pressure. I have not tried it, but it might be possible to unscrew everything except the valve by hand. The valve itself has pressure on the boiler side.
  • SlimpickinsSlimpickins Member Posts: 314
    edited April 2012
    How about a pic

    of your predicament. Like Jack said, try heat and use of a offset pipe wrench. If you can get a wrench on it, try the whack method and smack with a 5lb sledge in a rhythmic fashion. Using eye protection of course. Sometimes the sudden whack will loosen the bond versus brute strength. I know someone will say you should use a rubber mallet but steel hitting steel seems to work much better. You may need to cut the valve off and use a nipple extractor. Gotta use the tools you spent good money on plus a little finesse goes a long way.
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