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3/8" Pro PEX Connection Issues
I recently completed rough in of 2 residences using 3/8" Mr Pex tubing for the first time. After several weeks we went back to air test the systems before final flush and fill. I experienced roughly 80% leaking fittings (3/8" only all other fittings were leak free). I am using Uponor Pro Pex Rings (Mr Pex does not make these), Uponor brass Pex fittings, Uponor EP Manifolds, Milwaukee Pro Pex Expansion Tool with Milwaukee Pro Pex Auto Rotate Expansion Die. We tested the system at 35 PSI as recommended by Uponor for the EP Manifolds.
I attempted to fix the leaks through heating the connection/fitting. I tried to do this at various levels of heat. This approach was not successful until I heated the fitting until the Pro Pex Ring turned clear as is typical for fixing a kink. In the installation we did have to expand the Pro Pex Ring one time to get it on the tubing (uponor notes this as a possibility in their install manual), and then expanded the assembly 5 times to fully set it on the die. I did notice that expanded assembly fit quite loose on the brass fitting and therefore we applied a small amount of heat (hot air gun) to facilitate the setting time.
We have made literally hundreds of Pro Pex connections on all sizes of PEX and probably experienced a leakage rate of less than .01%. I did call Mr Pex tech support to discuss this issue and they could not suggest or recommend any thing differrent to our installation practice and that they had never heard of this problem before.
Has anyone else experienced this issue or can anyone offer some resolution?