A knockoff no name defective? Never.

Never put any of the no name ILLEGAL AND BLACK MARKET type faucet stuff in your home.

Its not a no name product - they sell it on Houzz, Wayfair, Home Depot and other sites.

You failed to read anything at the link. . It's a no name knockoff. Not at all a legitimate brand.

Thank you, I appreciate the info! I will relay that to our plumber and see where we get...

Valves behind walls should only be top name brands. It's behind a wall, and ripping out a wall to get to something defective is going to cost a huge amount. No plumber will warrant a homeowner supplied product, so if things have to be ripped apart, that's something you have to pay to do. And then redo. Which is why you use the plumber's supply house for selections, that HE purchases. He is then the warranty point, as is the LOCAL supply house.

I find it concerning your plumber can't determine the cause of the problem and you have to rely on others for help. Is this person a licensed plumber? Hopefully it is something simple and easily fixed.

I'm with Milke home,the biggest problem you have is with contractor you are using. Fix that and the rest will take care of itself.

1. True story. After I finished changing out a basin faucet and gave homeowner the invoice he asked about warranty. I told him my labor is warrantied 30 days and Delta faucet 1 year. He called two or three times the following week complaining that he could buy a lifetime warrantied faucet from Home Depot that costs less than the one I had installed. I liked the old gent so I told him if he would pick the facuet up I would switch it out and not charge labor,,,,BUT,,,, read that lifetime warranty very carefully and file it where he can lay hands on it if needed. A handle snapped off in a few months and he called to tell me home depot couldn't supply a replacement handle but would replace entire faucet for free. He asked if I would use handle from new facuet to replace the one that broke. I told him I would but there is a minimum charge for service call. Few months passed before another handle broke. He had returned the new faucet with broke handle installed under warranty. When he called to do the complete new faucet thing under warranty Home Depot said fine and he picked another up and paid with understanding he would get a refund when broke faucet returned. When I arrived the new faucet was different. He called Home Depot to find they couldn't order parts for his faucet. He paid me to install another Delta,collected refund under lifetime warranty and I never heard from him again but assured him if the Delta ever broke parts would be available.

Everstein Valve (one of many)

Delta rough-in valves are installed inside the wall with the pipes. Delta trims ships with a cartridge which slides into the rough-in valve. The cartridge can be removed and replaced without damaging the wall. Perhaps your Everstein valve is designed the same way and you can contact the company to obtain a new cartridge which might solve the problem.

Tankless water heater? I ask because I had this problem with a client. Turns out he Used the tub filler to draw hot water to the bath. When he switched to shower it reduced the flow so much that the wh turned off. If someone else was using hot water he would magically have no problems. Removing the flow restrictor in the shower head solved the problem.

@HALLETT & Co.

It can be a bit more complex than that - that's why I was suggesting they turn off the cold water and test it first.

If tankless, the water temp on the water heater should be no more than 120-125 degrees F.

The reason is that there's no benefit to turning it higher, and the downside is that mixing down a higher temp can cause the low flow shutoff (besides being a scalding risk). Note: People considering a tankless water heater need to look at those minimum flow rates before purchasing.

The other thing that can happen with any type of heater is that uninsulated water lines (particularly in a slab), in a low-flow situation, can lose all of the heat before it reaches the shower.

Absolutely Jake, I was just recounting what worked in one situation. OP hasn’t come back to answer questions so we are all guessing!

Yep! Ye ol football in a room full of monkeys syndrome.

Hi, I have been called an idiot for suggestion this, but I have experimented with this and I found water saving shower heads will cause that problem sometime. Some shower heads make the water streams so small in diameter that the air cools the water before it reaches the body. To test this, take off the shower head and run the hot water, Just don't scald yourself.

Good Luck Woodbutcher