I have old copper piping through most of my house. When I get a leak I just replace part of the old copper pipe with pvc.
Most recently I had a leak in my hot water side and changed out a portion of my hot water pipe that leads to my upstairs shower. After that I lost water pressure in my kitchen sink and my upstairs shower runs out of hot water almost immediately however if you flush the toilet you can get more hot water.
I have replaced the water heater and that didn't help my problem. I also checked to see if my pressure balance valve was stuck but my faucet is so old it doesn't have one.
What is my next step?