Shower volume control handle too tight

[Nick Liu]

Hello, I have no plumbing experience and need some help. Recently the volume control handle (the upper one in the picture) of my shower became too tight and my son cannot turn it. The thermostatic handle (the lower one in the picture) works properly. Because of the COVID, I would like to fix it myself if it's not too difficult, so I searched Internet. Some people said most likely it's the buildup in the cartridge and the easy solution is, either clean the cartridge or replace it. However, I'm having hard time to take out the cartridge. I used a wrench but cannot turn it with reasonable force ( I haven't put excessive force on it yet because I'm afraid of damages to the pipe/joints). I have some quick questions here, (1) what brand is this faucet in case I need to replace it? (2) did I do the right thing when I use a wrench to unscrew the volume control cartridge counterclockwise? (3) why it's so hard to remove the cartridge? (4) is there another way to take out the cartridge?
Thank you very much!

 

[Twowaxhack]

Use the appropriate sized socket and turn counterclockwise. Sometimes they’re very tight, maybe put in with impact wrenches at the factory.

I’m not sure of the brand. If you remove the volume control cartridge snd post pics we might can identify.

You might need to take detailed measurements of the cartridge to find a replacement.

 

[Nick Liu]

Thank you so much. I purchased a socket and a breaker bar and finally took out the cartridge. Can you tell from the pictures what brand and what model I should buy to replace it?

 

[Geofd]

Another thing you can do is take those pics to a plumbing supply house,the people at the counter see alot,so they maybe able to identify

 

[Twowaxhack]

It’s probably a generic cartridge. You’ll have to measure it with calipers and or take it to a plumbing repair parts specialty store like Geoff said.