In one of my 2 master bathroom sinks, the hot water pressure is only a fraction of what it should be. I have replaced the faucet and the connector from the value to the faucet, and still the water pressure is lacking. It is almost like the pressure is being blocked somewhere between the hot water heater and the on/off value under the sink, but then why wouldn't it affect the other faucet in the same room? I am at a total loss as to what it could be. What is my next step in troubleshooting? Cold water pressure is fine. Please help.

Jim

In one of my 2 master bathroom sinks, the hot water pressure is only a fraction of what it should be. I have replaced the faucet and the connector from the value to the faucet, and still the water pressure is lacking. It is almost like the pressure is being blocked somewhere between the hot water heater and the on/off value under the sink, but then why wouldn't it affect the other faucet in the same room? I am at a total loss as to what it could be. What is my next step in troubleshooting? Cold water pressure is fine. Pls help.

Jim

Hi Jim,

"It is almost like the pressure is being blocked somewhere between the hot water heater and the on/off value under the sink, but then why wouldn't it affect the other faucet in the same room? I am at a total loss as to what it could be. What is my next step in troubleshooting? "

BINGO! There is no "next step in troubleshooting". You did it all. You have localized the problem to the branch supply line that supplies the faucet. You know the heater main's not blocked because you have hot water pressure to the rest of your faucets.
What I think has happened is that some of the mineral built up on the pipe walls broke loose. The first faucet that made a draw sucked the crud up into your branch where it's now blocking the hot water flow to the faucet.
My guess that it's blocking the angle stop seat. Do this. Shut the water off at the house shut off or at the hot water heater shutoff and unhook the angle stop from the branch stub-out coming out of the wall. Now hold a pail over the open line and have someone turn the water back on. Is there a strong stream coming out of the open pipe? If so then the blockage is located in the seat of the angle stop and should be easy to remove once you unscrew the bonnet packing nut and stem and washer assembly to open it up. Good luck and let me know if you have more questions. Tom

Thanks for the quick response. I will give it a go hopefully this weekend.
Jim