Water leaks from shower head while bath faucet is running

Change shower. if u want repair open the controller and replace rubber washel.

hi mark.
this is all i could find on the internet,if this is no good to you go to the link at the bottom and see if it helps you out.
First, feel the water leaking from the tub spout or shower head. If it's warm, you know that the leak is coming from the hot-water valve. If the water has been dripping for a while and it is cold, the leak is probably coming from the cold-water valve. 1Start by removing the faucet handle.22 Nov 2016

How to Repair a Leaky Shower Faucet Valve - HomeTips

shower head leaks Google Search

My first suggestion is to have the installation plumber return to adjust the faucet to function properly

I can fix this.
What is the last thing you did before this problem started?

You need to order seals and replace them. Typically, dirt in the water system damages the rubber (neoprene, plastic) soft parts. Sometimes the damage wrecks metal parts, but this is less common.

Not unless you had a backward plumber , If the diverter at the faucet is open for tub, then no water will go up the shower, The shower may hold enough water up there to make it look like a drip, Even if the valve was leaking all the time, it would not go up, it would come out the faucet. It only works with pressure. Unless the valve was plumbed wrong,,, Hope this helps.

It sounds like the seals are going bad. Moen is probably rebuildable. You can go to a Menards and ask if they have the replacement guts for your particular model.

Try draining the system and apply air pressure (min 30psi) to each faucet. Open other hot water faucets to allow pressure to vent. Next try draining and cleaning the hot water tank.

Make sure the drip is continuous because the shower head will drip for a few minutes until it empties out. Replace the cartridge or washer kit if it keeps dripping.

If it is dripping from the connection where it goes to the water spout you can unscrew the connection and wrap teflon tape or Pipe Joint Compound on the Threads. Now you can Thread the Shower Head Back on, with No Leak. IF..... It is leaking from the Shower Head Itself There May Be a Problem with the diverter handle/lever. If it has a Pull Type Lever, sometimes you can screw the Lever up or down for the proper water restriction to the Shower Head. However if the Hot and Cold Handle/Lever is OFF, There should not be any Water coming out from anywhere! If water is coming out off the Tub Spout, with the Shower Off, then you will have to replace some washers or Cartridges in the faucet(s) to stop the dripping. You can do this easily....Just Ask) Remember though, that some shower Heads may Drip for a Few Minutes After they are Turned off. There is still water in the Supply neck and needs to escape, either though the tub Spout or Shower Head.......Hope this Solution Helps you with your Drips.....Joe