minimum water proximity to sweating

snugone

Am still new to sweating copper pipe, though I do pretty well when I know how to avoid situations less than ideal to solder in. My question is along those lines. How close can I get to a section of water filled pipe before there's too much heat draw and soldering becomes tricky?

PHOTO OF PIPE SECTION

The male adapter pointed to by the green arrow is leaking from a crack in the solder. I plan to close off the balance valve and drain the boiler just enough to get air into the area around the leak. Because I hope to replace that leaking adapter with a union, I will be cutting the 4" section of 3/4" pipe right in the middle, which will mean I'll be soldering a mere 2" from the shut off balance valve which will be holding back the zone's water. I could drain the zone and avoid any potential problem altogether, but I'd like to avoid that if it really shouldn't pose a problem.

hot_rod

As long as you can heat the tube to the melting point of the solder. If you solder too close to a ball valve, often you can boil the water inside the closed off ball and pop the seal, the valve will now leak thru and be almost impossible to solder.

I'm not to sure you will get 100% shut off from that balance valve? is it a ball, or butterfly type?

Another concern is heating up the threads and developing a leak at the copper to steel ell connection.
Usually you sweat the pipe into the copper adapter, cool it off, dope and thread it into the thread and then solder the valve down from it.

Has that valve ever been balanced, or just used to purge? You might look at a Webstone purge valve replacement.

Have a plan B, you may end up needing more room and a complete rebuild from copper adapter to a new valve.

snugone

hot rod said:

I'm not to sure you will get 100% shut off from that balance valve? is it a ball, or butterfly type?

According to Watts it's a "self-contained, tight seating ball valve ideal for pipelines that require exceptionally high capacity purging", and "also serves as a shutoff valve". Not that that's any guarantee it won't still drip.

hot rod said:

Has that valve ever been balanced, or just used to purge? You might look at a Webstone purge valve replacement.

It's always been kept in the fully open position, but it's also the only zone on the system.

hot rod said:

Have a plan B, you may end up needing more room and a complete rebuild from copper adapter to a new valve.

I've already picked up some extra feet of tube and couplings for that plan B if it comes down to that.

SWEI

Can you open a vent on the water side?

snugone

SWEI said:

Can you open a vent on the water side?

There is a manual bleeder at one of the baseboard registers on that zone which I can open. Would there be an advantage to that? I guess half of the zone can be emptied that way, which is better than draining the whole thing.

hot rod said:

Usually you sweat the pipe into the copper adapter, cool it off, dope and thread it into the thread and then solder the valve down from it.

I'll have the mxC union apart when I do the sweating, so that should avoid overheating the threads on the side going into the iron pipe.

hot_rod

There is a manual bleeder at one of the baseboard registers on that zone which I can open. Would there be an advantage to that? I guess half of the zone can be emptied that way, which is better than draining the whole thing.

You need to have the downstream side open or when you heat up the joint you build pressure and will blow out the solder. in a short section like that, if you have it isolated it will be tough to solder.

snugone

hot rod said:

You need to have the downstream side open or when you heat up the joint you build pressure and will blow out the solder. in a short section like that, if you have it isolated it will be tough to solder.

If I put in another male adapter such as what's there now, then I can leave open that ball valve that's sticking out perpendicularly from the iron pipe, just above the level I plan to drain the boiler to. It's currently just capped with a clean-out plug, which maybe I can remove with a 1/2" ratchet.
But if I go with the idea of replacing it with a union, which is my current plan, leaving the union open should keep inside the soldering point at atmospheric pressure.

By the way.. though I intended to right that image before posting, I apparently forgot to. The left side of the photo is facing towards the floor. Don't know if that makes any difference.

hot_rod

Don't use a copper to copper union, they are leak prone. Use a 3/4 black steel union then adapt into that.

Or I can send you nice brass this transition union that seals with a gasket. You need a 3/4 nipple in the FIP end, then sweat onto the copper.

Yes with the union loose you can solder without a pressure build up.

SWEI

Who makes those, Bob?

hot_rod

We have them in the catalog as sweat by sweat, but I can modify it to about anything.

For that example, above I swap in a 1 X 3/4 bushing.

In the example below, a sweat X male. Hemp thread on the male end.

I hope to beef up the fitting selection next catalog. All the parts are in there, just selecting the match up is complicated.

Choice of high temperature red silicone or green fiber washer.

Let me know any special requests.

SWEI

Are these ISO (aka "Nut G") union threads?

If so, we could use half unions to transition from Aquatherm or F1960 PEX.

hot_rod

yes a G thread on all the nuts.

The main point with transition fittings that use gaskets is the face needs to be milled or sanded flat for the gasket to seal. A gasket doesn't seal on the end of a threaded pipe, for example.

Here is how I converted some MIP valves into a valve that would accept a garden hose connection and washer.

Hilly

wouldnt you still need the garden hose to have a FIP thread to match the valve. I do love your ingenuity as a whole though. Outside the box is clearly something you do well.

SWEI

We buy Webstone 40313W's by the case -- best water heater drains ever.