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Zone valve sweat connection

Ewan Member Posts: 45
I'm a homeowner currently working on the distribution piping for retrofit hydronic baseboard installation. The system has been designed by a reputable and professional radiant design firm and I'm hiring a contractor for the boiler installation and gas work.

I have Erie zone valves with 1/2" sweat connections that I've been having a heck of a time soldering successfully. I'm removing the actuator and cleaning/fluxing as I normally do with wrought and cast copper fittings (which I can sweat successfully).

I'm using Silvabrite and aiming the torch at the base of the socket on the valve body (heating the bottom of the socket from side-to-side). I can't seem to get a continuous bead to form all-around the joint. When I attempt to fill-in the section that hasn't formed a bead, it pulls solder from, and/or bubbles the area that was previously nicely filled. Results so far include lots of bird-poop joints and aggravation.

Do the heavy brass valve bodies require different soldering technique?
Any tips from the pros would be most appreciated.


  • Weezbo
    Weezbo Member Posts: 6,232

    take them apart, re clean them,flux the pipe (i hope you have gotten the water out of the valve and have it open)and valve,put heat on the Valve socket then the other valve socket just enough to bring it up and disperse heat then heat the pipe or fitting and move your flame back at the valve slowly soon as it takes put the solder to the back of the pipe or fitting and put the heat back on the socket..cool with a wet rag the center of the valve ...if you are using the silverbrite dip the end ofthe solder in your flux tub before applying it to the joint. erie valves are excellent valves why not let the boiler guy do it and call it a day.
  • Betz
    Betz Member Posts: 58
    I also had a time

    sweating a zone valve recently. I had the tiniest drop of water from a new gate valve coming into the sweat fitting, and of course I couldn't get it to sweat. So I had to remove everything so there was no way for water to contact the zone valve and it went really quick.
  • Ewan
    Ewan Member Posts: 45
    Zone valve sweat connection

    Thanks for the replies.

    Everything's still on the bench so water in the valve isn't an issue, and yes, I have the valve open.
    Stubbornness and the desire to do it myself are the only things preventing me from handing it over to a pro.
  • Weezbo
    Weezbo Member Posts: 6,232
    ok then use 50/50

  • hr
    hr Member Posts: 6,106
    What type of flux

    the current water soluable fluxes burn very easily! In fact within a few hundred degrees of the solder melt point.
    To make it worse the no-lead solders have a higher melting point. Try to find some 50/50 solder.

    Don't use core solder acid or rosin!

    Everything clean AND oil free? Heat all around the base of the valve and take away the heat as soon as the solder flows to prevent burning the flux.

    After you get the hang of it, disassemble a few joints to check.

    Over fluxing is another common problem. A very thin film to cover the tube AND inside the valve body. too much flux can cause bubbles and a poor joint. When you disassemble a soldered joint and see un-soldered pockets, (clean copper and shinney brass)this is often a sign of over fluxing.

    Not a very big tip at all for 1/2" fittings. This is another common error that causes overheating. Too many BTU's:)

    Takes practice, but it can be done.

    hot rod

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  • Ewan
    Ewan Member Posts: 45
    Thanks hot rod

    for the reply.

    I'm using Oatey No.5 flux with Silvabrite solder, a combination that has worked beautifully for me up until this point.

    I'm cleaning the outside of the pipe with plumber's sanding cloth and the socket of the valve with a fitting brush.

    Because I've disassembled a few times, the ends of the pipe and, to a certain extent, the valve socket are now tinned... should I be sanding down to bright copper each time?

    I'm pretty careful with the flux, but I'll take special note to keep it to a minimum.

    I'm using a Surefire T111 propane torch with the general purpose tip.
  • lchmb
    lchmb Member Posts: 2,997

    I think they recommend using 50/50. The lower temp is better for the life of the valve...
  • hr
    hr Member Posts: 6,106
    Gosh, you've got the right stuff

    No, don't sand off the solder (tinned areas) this will help you get a good joint. Some installer actually pre-tin larger size pipe to assure leak free, solid, solder joints.

    hot rod

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  • Robert O'Connor_7
    Robert O'Connor_7 Member Posts: 688

    You say everything is still on the bench? Whats everything? If the valve is open and the fitting is fluxed and the right amount of heat/tip is being used and water isn't an issue than I can only guess that the ends are capped off and pressure is building up due to the heat forcing the solder out. Why not cheat a bit and start by doing one side at a time with the joint in the vertical position and let the solder puddle up on top making a nice cap. If this doesn't work, change solder to 50/50...Robert O'Connor/NJ
  • Ewan
    Ewan Member Posts: 45
    Thanks Robert

    for the reply.

    I'm building-up the return and supply manifolds for a 4-zone baseboard system. Neither manifold is connected to any loops or boiler supply at the moment.

    On the upstream side of the zone valve I have a short stub of tubing and then a ball valve (in the open position). On the downstream side I'm sweat-connecting a simple length of tubing. There are no closed or capped ends.

    I'll give it a try vertically.
  • Dave Palmer_3
    Dave Palmer_3 Member Posts: 388

    a tinning flux if thats what you're not using already,Dave
This discussion has been closed.