Hi, I turned my water off earlier today to change a broken shutoff valve under my bathroom sink. Now that I have turned it back on, however, I am getting low hot water pressure in my downstairs kitchen, and no hot water pressure upstairs in the shower (I haven't hooked the new sink up upstairs yet, though, so I don't know how the bathroom sinks pressure is). Any help please?
Sounds like debris from the heater tank flushed into the lines and has probably clogged the aerator on the kitchen sink and the showerhead. Remove them both and then try the hot water pressure. If that was the problem, that should resolve it.
To clean the aerator and showerhead, you may want to soak them in vinegar overnight to dissolve any mineral buildup in them and then rinse and clean them out.
Whenever turning off water to work on plumbing, it is best to open tub faucets first (no spout aerator to clog) when turning the water back on. Let the water run until all air and possible debris are flushed out of the lines.