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Spirovent Leaking at Sweat Connection

TimNT424 Member Posts: 2
I have a 1" spirovent with a sweat connection on my hydronic heating system that has developed a pin hole size leak at one of the copper connections. There is a bead of water that comes and goes. Typically when I've had a leak on any soldered fitting, I've cut it apart and discarded the fitting and just used a new one. However, at $100 for a new spirovent, I was hoping it may be possible to reuse the old one by sweating it apart, cleaning, re-fluxing, and putting it back together. Any suggestions on cleaning it and re-using it? Or should I just buy a new one to not risk another leak. Thanks for any help with this.


    HVACNUT Member Posts: 4,859
    Sure you can. Close any isolation valves on the return and supply, after the Spirovent. Drain the system. Remove the plug from the bottom of the Spirovent. If there's play in the 1" copper, you should be able to un sweat it. Use a 1" turn brush to clean the female port to the Spirovent while it's still hot. Add a little flux inside and heat and clean again. Cool it down. Clean with steel wool.

    Sometimes you don't have to take anything apart. Drain boiler. Clean the area of the leak. Heat the connection, and once the existing solder flows, hit it with flux, then apply a small amount of new solder. Cool down and wipe clean.
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,968
    edited December 2019
    Is the actual pinhole on the spirovent itself? If so, I would replace. But I'd also would check the PH of the water. If it caused a pinhole in one spot, more are probably to follow.
    If it's just the solder connection, maybe it was just a bad soldered joint, too much flux, not enough, too much solder, not enough.
    Edit: I think @HVACNUT types faster than me.
  • TimNT424
    TimNT424 Member Posts: 2
    Thanks for the help. Steve it's definitely the solder connection and not the spirovent itself. I put it in when I installed the indirect water heater over the summer. I used mapp gas to originally put it in, but it's a lot of brass to heat up and I couldn't get the flame around the back of it with the wall. I didn't want to overheat it and wreck it either. It started leaking shortly after installed, and I tried the easy trick of reheating and adding new flux and solder. That stopped it and I thought all was well, but with winter and the system running more unfortunately the leak returned. I probably should have went with a threaded spirovent and adapter.

    Thanks for the advice hvacnut, there's unions before and after so I can definitely disconnect everything and un sweat it. I will take it all apart and clean it like you said, then sweat it again on the bench this time.
  • Ironman
    Ironman Member Posts: 7,067
    You can unscrew the top and remove the guts if you’re concerned about overheating it. You may wanna do that in place with a 24” pipe wrench.
    One tip about sweating large brass to copper: the copper conducts heat away very quickly; the brass not so. Therefore, heat the copper first near the socket. Then move around the brass.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • HomerJSmith
    HomerJSmith Member Posts: 1,923
    edited December 2019
    Homer's first law of plumbing--"If the rate of evaporation exceeds the rate of drip, you don't have a leak."
  • HomerJSmith
    HomerJSmith Member Posts: 1,923
    edited December 2019
    I very much doubt that the Spirovent has a pin hole leak unless it is observable. More than likely, it is an incomplete solder fill on the joint.

    You have to heat the pipe and the brass fitting to get a complete solder fill.