On Sep 3, 6:43 pm, Speedy Jim wrote:
David wrote:
On Sep 3, 6:07 pm, David wrote:
SNIP

The pressure could be a problem. I had a PEX joint start to leak
about a year ago, and the plumber (who didn't have a pressure gauge)
turned down the pressure regulator at the main shutoff (it was wide
open). Perhaps it needs to be turned down even further.

You misunderstood. The pressure regulator *is* the problem.
They contain a check valve which prevents the expansion
pressure from dumping back to the city main. That's why
the expansion tank is needed.

But do the bucket-under-the-relief test before doing anything.

Jim

Also, TPR valves do go bad and fail to seat properly. Before I call
in a plumber, I'd find out for sure where the water is coming from,
which shouldn't be hard. It could be that you need an expansion tank
as suggested. But it could also be a bad TPR which is available at
home centers or plumbing supply and if you're at all capable, it's a
quick and easy replacement for $10.

As to where to try to route the water from TPR to, impossible to say
here without seeing where it's located.