I I have a 3 way bath/shower/overhead shower mixer valve to fit and am not sure where the pipes should go, there is a hot and cold feed in, but only 2 feeds out, I need feeds for 1. bath filler, 2. overhead shower, 3. also for flexi shower??

Hello Mark Bentley,

In California... (MY OPINION... every bit)

It is called "social engineering".

FOR More than 25 years... before "the drought)
and without public knowledge MY state mandated
water flow restriction at the VALVES

Although the shower VALVES... were MAUFACTURED
prepared for 1/2 inch PIPE FITTINGS... FINAL
MACHINING severely reduced the holes through
the side of a typical body... were smaller than the
EASILY altered WATER RESRICTERS IN EVERY
shower-head & faucet NOW sold in CALIFORNIA...

Back then... That was 1½ or 2½ GPM
water restriction... (I don't remember which).
It was part of the VALVES CONTRUCTION...

I am PRETTY SURE you are going to have to call
GROHE and find out if there is ANYTHING they
can recommend... now that your VALVES
are installed & finished over... What can increase the
allowed water FLOW...

Only a traveling DENTIST would have the tool
to work from the INSIDE of the valve...

Just my opinion...

Carnac the Magnificent

most electric hot water systems use a heat transfer process where the element is in one tank and the house water is in another
the house water is what is being drawn off when you turn on a tap
there is a regulator valve at the top of the tank with a small lever that you open up to let water in and air out of the system
another point is that there may be a hot/cold mixer on the hot water outlet which limits the temperature of hot water to prevent scalding injuries in the bath and shower or sink
If you have one fitted they are known to malfunction and cut the hot water temperature down as, they mix too much cold water into the hot water pipe.
have a plumber check it out

a couple of things to check on the side of the hot water system you will see a valve with a small lever
lift that lever until there is a solid stream of water coming from the pipe
that ensures that the heater tank is full
next -if you have a temperature mixer on the hot water pipe out of the tank ( stops scolds in the bath, shower sink) by controlling the temperature mix at the tank
They are known to fail and shut down the hot water supply by adding extra cold water into the system
other than that get a plumber in to fix the fault.

you make no sense. From the picture the water "mixer" is the center lever or is it a diverter valve for the shower and water nozzle below???
The knobs are for hot and cold water??

sounds like either the cold water that feeds the other half got shut off, or the mixer in the valve for controlling the water temperature is broken....most likely the water got shut off. better go to the water source and trace the cold water feed pipe ,looking for a shut off valve....it could also be behind the shower panel, then turn or rotate the valve the other way and go test the water to see if you can adjust the temperature now.....if not, then replace your hardware.......in the mean time, you could turn the temperature down on the water heater so that you won't scald yourself in the shower til you have time to fix it properly.

probably have a kink on how water line feeding valve..if possible to cut drywall bhind tub valve and inspect pipe at bottom plate...moen faucets are equipped w/ anti scald device, pressure balanced (newer models) and this could cause cold water to overwhelm hot water...

Probably some pipe rust clogged the exit.
If u have pretty low pressure on one or both, hot and cold water, try keep force closed by hand the water exit at shower pipe, then start both cold and warm water gradually as much as u can keep it closed with the hand.
The pressure of the water will try "escape thru the clogged pipe and hopefully unlock that debris or rust!
The hot water pressure going back thru the cold water pipe might unclog that debris.
Just a simple fix which many times works as a charm..
Otherwise if this is not fixing, try close both water from main service valve.
Then unscrew the secondary shower valves and manually clean them or replace if very damaged.

I suspect you have gravity fed hot water system and the mixer cannot balance the high pressure of the cold mains against the low pressure of the hot water.
Either install a shower pump. Means installing electrical connections and quite a bit of plumbing
Or a mechanical pressure reduction valve on the cold input pipe to the shower

This sound like you need to reduce the inlet pressure of the cold feed to the mixer. If there is no 'non return valve' fitted and the cold feed pressure is too great, i can in effect push back the hot water feed and reduce the temp. So how to fix?? trace back the direct water feed to the shower faucet/outlet feed and simply reduce its pressure by 1/4 turning the 'in-line' stop valve the plumber should of fitted if he was any good at his working standards.

Hope this Helps

AndystUK

mixing valve must be replaced