Plumbing Xperts?

Having trouble with a hot water circulation pump. Keep getting pinhole leaks downstream of the pump. Appears to be galvanic corrosion, with pump as the source of the problem.

Edited by modirt - 12 Nov 2020 at 11:21am

YEA... that pump puts out 6 GPM... You need one about 10 x smaller... If you were moving a quart or 1/2 gallon a minute, that would be all you need.... Your lucky to get 1 GPM out of a faucet, and your moving 6 x that much water !!  FRICTION .

Fitting is thicker. But turbulence it creates affects the piping downstream. Would also recommend type L copper as it is thicker than M

Not entirely sure which way to turn for slowest setting. You should be be able to hear the difference from one extreme to the other. Grundfos has low volume recirc pumps for this application. Check model number UP10-16. Also check out Laing E1. They’re imported but I have installed a number of them with no issues. They have a timer attachment available that is 24hr programmable.

The data plate shows amp/watt rating. The screwdriver slot changes the route through the windings. This controls motor speed vs closing a valve

It boils down to this:
Flowing water erodes metal pipe.
Anything that affects smooth flow(burrs,bends, tees, etc.) causes turbulence. Turbulence accelerates erosion. Doesn’t matter which side of the pump your on. To that end the will relate a story. Several years ago as service plumber I was called out to a single story motel with 60 rooms. As can imagine that is a long way for hot water to travel from mechanical room to end unit. In the span of a week was called five times to repair a leak in the recirc line. Each time a different location in the same run. It was a straight run. Point is, it just wears out the pipe in relatively short period of time.

Since your copper is all shot, anyway, replace with pex, its cheaper, and don't corrode.  JMNO!

I did in-laws house trailer in PEX to get away from the steel-copper piping in the crawl space.. Took paneling off a couple walls to install some... then ran across the ceiling in  bathrooms and laundry room... built a FAKE wood beam to cover the tubes afterward... Worked great.... 45 years old so was a good time to install new faucets  / shower head / etc.

Edited by steve(ill) - 12 Nov 2020 at 5:56pm

Looks like from the picture of the 45' fitting, you have high sodium water. Going to a reverse osmosis system will solve your problems. 

I agree RO water should not be used copper pipe system. I didn't read the postings close enough.

K99, because the more purified the water, the more it attacks metals and absorbs minerals. RO is extremely pure, and begins to dissolve any metal it comes in contact with and therefore copper would not last long at all.