Dresser coupling with galvanized pipe

[shnaig]

I'm repairing a rusted out 1/2" galvanized pipe in the wall which went to a spigot for the washing machine. All the connections were pretty seized so I had to cut the pipe. I'm using a dresser compression coupling to connect the old cut pipe to the new installed pipe in a vertical installation. The new section of pipe comes out of the coupling to a tee and continues upward creating an air chamber which is capped. The problem is when I turned on the water to test for leaks the new section of pipe popped out of the dresser coupling. Is this to be expected because the new section was unsecured? Is it a requirement to have both ends secured from movement when using this type of coupling?

[hj]

First, "Dresser" is a brand of fitting and they make several different couplings. Which one did you use, the one with "screwed" nuts on either end or the one with "draw bolts" on each side. IF the pipe can move longitudinally, then there should be some restraint to keep it inside the coupling.

[Stihlworking]

Similar problem- I've got really old 3/4" galv water line from street meter to 1912 house. It is leaking .375 gallons a minute at a coupling in the yard. My solution is to use a Dresser style 4 or 41 coupling which tightens split follower rings around a gasket and seals the existing coupling at the threads instead of cutting the pipe and using a style 38 coupling or equivalent. Any one use these before or know where to get them? Dresser only sells to wholesale distributers and I cant even order from them. Any online supply houses?

[Gary Swart]

Not an answer to your question, but if the rest of galvanized pipe is as old as you imply, you're wasting your time repairing it. The entire line needs to be replaced. It's only a matter of time, and likely a short time, before more leaks show up. Galvanized pipe has a fairly short life span, usually somewhere around 40 years.

[Stihlworking]

I agree, just trying to buy a year or so to finish larger projects.