I moved to a new house and found the shower has a very slow flow. The temperature is ok, though. The nearby sink runs properly with normal cold or hot water pressures.

We have only shower, no tub. Removed the handle and escutcheon, and the cartridge after I shut off the water with the two stops on either side. These are what I saw (click the links for images).

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Anyone have an idea where is problem could be, cartridge, balancing spool and/or shut-off screws? We are in an area that water is not hard.

What kind of cartridge is it? There seem to have seats and springs in the upper delivery holes? I am going to pull it tonight. No idea how to test the pressure for hot and cold. Don't want to shut off the main supply for the whole house.

Any input is appreciated.

Thank you,

Charles

? did you test the flow through the 'shower arm' with the shower head removed ?

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Yes, I did. That gave also a very low pressure.

He should buy a new Cartridge and clean the inside of the valve with white vinegar and rinse then lube the oring prior to reinstallation

Cartridge looks like a Delta RP1991.

Usually Delta will put their name on the escutcheon plate....so maybe somebody used Delta cartridge in their valve body ?

Have you tried running water thru the body with cartridge out ?

Thank you, Lorensr (CA).

I am not sure what brand of cartridge I should buy. This is an older Delta faucet.

Will try to disassemble the insides when I have time.

Hi Curly (CA),

Sorry just missed your message. I will check about the cartridge.

Have not run the water without cartridge. Will need someone to carry a bucket while I turn on both pipes.

The balancing spool part number is RP574.

I'm not familiar with Delta's spool but if it is like other manufactures it is made with very tight tolerances and the spool just may be hung up. If you can get it out and soak in vinegar or something similar.

The screwdriver/check stop assembly is part number RP2090.

I can not tell from the pictures, but if I remember correctly this is one of the Delta valves where they connected the brass valve body to brass cup that cartridge sits in with 3 copper tubes.

When removing/install the cartridge retaining bonnet it does not take much to twist the copper tubes and then you are screwed. If they leak you will have to replace valve body in wall.

Run water without the cartridge and work backwards until you find the blockage.

You could also contact Delta for troubleshooting advice and they might send you free parts under warranty.

This valve may have been made before they started giving out lifetime warranty.

Good luck.

Curly (CA),

Thanks a lot for all the details. I will give it a try carefully. Hopefully I can remove stop screws and balancing spool without an issue.