Low Pressure Hot Water Only in Shower

Question

We had to shut the water off to the house while we were hooking up a new sink in the kitchen. When we turned it back on, everything works great except the hot water pressure in the main floor shower. The cold is fine. We took off the water spout in the tub and looked at the water pressure coming out of the wall pipe. The cold was normal and the hot was very low pressure. We've tried shutting it off and back on again and it made it worse. Thanks for any suggestions!

Answer 1

Do you have a balancing valve on the shower? Yes? Try changing this first. Do you have galvanized water piping.  If yes, there is a blockage in the hot water line. Try turning off the water supply and shooting air pressure back through the line to as close to the water heater as you can get. Maybe disconnecting the water heater hot line. This method may take several attempts to clear the blockage. And you may have to do the whole house this way eventually. The air pressure picks up little pieces of rust and scale and actually uses them to sand blast the insides of the lines. I have done this many times but it is a job that takes patience. Of course all the strainers will have to be cleaned and monitored for a while.

Answer 2

You likely have a hardwater build up in the hot water pipe.  You could try to run a snake down the pipe but that is only a temporary fix.  In my community we find that using copper pipe instead of galvanized pipe keeps the buildup down.

Answer 3

Turn off the hot water outlet from the water heater and remove the stem from the faucet.There is probably some scale deposit there from the heater bottom. If that doesn't work you may have to remove the entire faucet to clear it.

Answer 4

Hi i think you better have a plumer have look  

Answer 5

There could be a blockage in the diverter valve that is in the shower on/off handle. It could be a blockage in the piping on the hot side. If you have the old, galvanized pipes, it's most likely sediment or rust.

Answer 6

i can give you detailed instructions on exactly what to do. if you can take a pic and upload it or email it to me. if you can't, tell me if you have two handles on your shower faucet or just one? What brand, and app how old is it?