I had a shower head that had very low pressure that was getting worse. I replaced the cartridge and now it is low pressure leakage all the time and has no pressure when it is on. It essentially just goes nonstop at the same very low pressure. This is an old set up and I can not see anything else that could be replaced. Could the cartridge be bad? or did I miss something, put it in backwards? I am not sure you can mess up how it is actually in there
I found the leak issue. My pipes are weird and the cartridge has to be rotated a different way from the demo. This resolves the leak and the lever is much smoother, but I still have low water pressure in that shower. Is there anything else that could cause this? The sink faucet does not have this issue. I am wondering if it could be mineral build up?
is your plumbing copper. pex or galv? If galv ur problem could well be the pipes themselves. If Not then could be dirt/crud buildup in the shower valve body. Is there a way you can pull the cartridge, get something to catch water, turn water on and flush that valve body? See if the pressure will blow it clear. This will also tell ya where the problem really is, if it is wide open and there is no pressure than you know it is in the body or piping.