New Delta install - Now leak at Shower Head

We put in a new "surround" for our tub/shower, and also installed a brand new Delta kit from Home Depot for the tub faucet, main valve & handle, and shower head. We cut the hot & cold copper water lines after the shutoff valves and switched everything after the on/off valves over to CPVC. Everything works great EXCEPT that there is a leak at the shower head.

When we turn on water flow at the handle (to run water into the tub), cold water comes first. At this time, nothing leaks from the shower head. We slowly increase flow, still no leaks. As we gradually increase flow, the shower head starts to drip. More gradual increase and the drip becomes more of a weak shower flow out of the shower head. All this time, water continues to come out of the tub faucet as expected. By now the hot water has combined with the cold. As we continually increase flow with the handle, then shower head leak then starts to slow down. As we increase flow with the handle all the way over to HOT, the shower head leak stops.

I tried taking off the tub faucet and just let the water flow out of the pipe into the tub. The shower head still does the same thing.

So the shower head is leaking when there is flow from both hot and cold, but not when there is flow from just one or the other.

Any ideas?

Sounds like when the hot and cold are both being mixed in, that there is too much flow for the spout to handle and the excess flow is being diverted thru the shower head...possible restriction in the plumbing to/thru the spout.

There is a up and down on the shower valve. Was the valve installed correctly?

The up/down on the valve shows correct installation.

I also thought it might be a restriction somewhere to/through the tub faucet, so I tried partially closing the incoming water valves to reduce the amount of water coming in - in the first place. Even with very little flow from the water lines, the shower head still leaks.

Any other ideas?

Sounds like a bad mixer valve. You an either try to replace it, or you can live with it, or you can install a showerhead shutoff valve.

Good luck.

Do the directions show a specific distance that the shower valve has to be from the shower arm?

Any chance the mixer is installed upside down?

Did you use 1/2" cpvc between the valve and the tub spout? If so, that is too much restiction and back pressure, causing water to back out of the showerhead.

kordts... would that be true if the shower pipe is of the same material? Whatever it is...they should be of the same material.

CPVC is the problem

and it should of never been used for the makeup of that valve between the tub spout and showerhead.


States that in print in the instructions for DIY'rs.

Rip it out and do it over in copper.

valve

I assume you used CPVC for the line from the valve to the diverter spout. If so that is the problem. It HAS to be either brass pipe or copper tubing. The riser pipe is not as critical but ideally should be the same.