My wife and i recently lost all hot water in the
house. Called a plumber and he traced it to a "spring" (dont know exact term) in my boiler. My boiler is only 5 yrs old but all the piping is @ 80-?? After the replacement, we had hot water and good pressure everywher but the bathroom sink. He recommended replacing about 50' of 3/4 threaded pipe that was causing the problem. However, I don't know why only this faucet and only the hot side was affected. Sorry this doesnt help but glad to see I'm not the only one. The old piping was causing sediment buildup in the "spring" in the boiler. He mentioned it could be specific piping or shut off valves related to this faucet.