pipe dope on pex???

Old 06-14-2019, 08:11 AM
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Default pipe dope on pex???

A relative recently reworked part of a plumbing system on his 3 year old house. The plumbing system was installed by a licensed plumber.
when reworking one section of the hot water recirc system he noticed a white residue and build-up inside the pipes. The residue was formed in bubbles or nodules on the inside of the fittings. The material holds together but will crumble if you squeeze it.
He also removed some fittings from the pex and found white reside on the interface between the pex and the fitting (ridges). It looked like oxidation (just a descriptor, HE DID not think it was oxidation).

He thinks the plumber put pipe dope on the pex fittings.
I searched around on the internet and did not find recommendations for this practice. If it is a practice, I would be interested in a comment on material compatibility. This is hot and flowing water.

Has anyone ever heard of this, or have an idea of what it might be?
Old 06-14-2019, 08:14 AM
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calcium deposits from the hot water heater maybe?
Old 06-14-2019, 08:15 AM
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Mineral build up? Couldn’t imagine even the dumbest plumber using pipe dope. Also all the pipe door is usually other colors not white.
Old 06-14-2019, 08:21 AM
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Are the fittings plastic or metal? There were historically issues with brass fitt8ngs but three year old fittings should not have this problem unless something inferior was used.

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