Installation of multichoice valve trim series 13/14

It's possible you installed the valve upside down, all values should be labeled in some way marking either hot and cold or it will say the word up where the riser tube port for the shower head is. If that's not the case remove the tub spout and check for any obstruction sometimes during tile or constructing debris can get into the pipe for your tub spout. Lastly the diverter on the tub spout could be bad. Try a new tub spout

When you turn off faucets other than your tub or shower you will note that the water stops fairly abruptly. Not so with a shower head or tub spout. Some water always dribbles out even after you have turned it off. This small amount of water then evaporates leaving behind the iron that was dissolved in your water. This also happens if any faucet has a slow drip. There are products that will easily remove the rust stains. CLR, Iron Out, or Iron Ike are all good products that will remove the stain. Available at hardware stores, plumbing supply houses, and, ugh, Home Depot or Lowes. Please support your local business owners by purchasing there.

Sounds like the delta people forgot to install the diverter piece inside of valve body,small white plastic piece screwed into valve. If you take out valve you should see it up inside body

If you look inside the shower head from the back where the threads are you can see a flow restrictor, if you take it out you get a lot better flow.

most likely problem is to much pressure in water lines if u have shut off valves on to feed lines turn them down a little will decrease pressure to the valve other problem the spout {tub} diverted is partially engaged, loose,debris or defective if u can reremove the spout and observe the valve for proper function

The shower valve is clearly mark "UP" when you look at it from the front.

The only possible explaination is that the water is finding it easier to go up than down. Water is lazy, just like me. ;)

Use an allen key to remove the tub spout. It's underneath and awkward. Once the allen key is loose, the spout just slides off. Try running the water. This may solve your problem and all you'll need is a new tub spout. If not.....

Turn the water off to the house.

Use an allen key to remove the handle.

Use a phillips to remove the trim plate (2 screws). Cut the silicone around the trim if it's there (which, in a proper installation it shouldn't be, but...)

Unscrew the nut (usually chrome) holding the cartridge into the brass body of the valve. The cartridge pulls straight out. Check for restriction in the ports of the cartridge itself. Check for restriction in the line going down to the tub spout. If you can't find anything, replace the cartridge.

Reassemble & Enjoy!

This is what you should have... Grohe Grohmix Thermostat Valve & Trim - 34436

Paraffin cartridge

Lever volume control

Grip ring temperature control

1/2" NPT female connections

Service stops

Includes rough-in valve and trim

Integrated temperature and volume control

Requires Twin Ell (03 671) for shower/tub combinations with diverter spout Note:

Requires Twin Ell (03 671) for shower/tub combinations with diverter spout

Grohe Grohmix Thermostat Valve & Trim - 34436

Does the tub spout water flow stop when the shower knob is pulled?

Was the systems pipping flushed before the shower head was installed?

It may be clogged, remove the shower head and then attempt to operate. If it is clogged you will see debris trapped in the screen at its connection point. The shower head can be disassembled - cleaned - reassembled

Is the shower head an adjustable type, that may be in the off position?

Good luck
Aduz

it must be the same model number,most models come in different colors and styles.