I have a problem that I have no idea what it would be. Here is some background on the house. My home is two story, pier and beam built in 2000. I have two gas 50 gallon Lochinvar hot water heaters, still the orginal, with a hot water circulating pump (which was replaced in 2012). The design is water is drawn from each heater equally for the whole house. There are only 2 people my wife and I living here. Our master bath is large and living in Dallas TX no need to heat floors, but during these cold days my wife prefers using a smaller guest bathroom with her little space heater. All bedrooms are on second floor. The bathroom she is using is were my problem lies.
Only, I mean ONLY the tub / shower hot water value when turned on what comes out is water that is dirt brown or no offense to UPS but UPS BROWN. Sink in the same bath hot water is crystal clear. NO other hot or cold faucet in the house does this. I have outstanding water pressure, about 80 psi. I use 6.6 gallons per min and my temp dial setting is just about set at medium and I have about 115 to 120 coming out of my utility sink in my garage which is about 6 feet from the heaters.
I am far from being a plumber which I realized that about 25 years ago single in a townhouse when I tried to impress the new neighbor (female of course) by replacing her kitchen sink. It took one day to demo, replace two cabinets, title back splash, install new light, run new pipes, set sink / faucet and ONE day to give myself a 2 inch cut on forehead and burn 3 fingers trying to solder 4 yes 4 couplers. Thank God for SharkBites. So let just say I know enough to be dangerous with plumbing.
Thanks for any advice or scratch your head and get a good chuckle like i did writing this and thinking about the good old days!