Poor hot water pressure to shower head

[Mitch H.]

Hi all. I own a duplex in Denver and my tenant has recently informed me that the hot water pressure to her shower head is poor. I have not been over to check on it yet but she gave a pretty good description of it (below), so thought I would see if anyone here had insight. Thanks! "There seems to be something that's keeping water from getting to the shower line. I've replaced the shower head to confirm that that isn't the problem, to no avail. Currently, I get about 5 minutes of decent water pressure with appropriate temperature. After that, the options are to turn the lever far to the left to get hot water with no pressure, or turn it to the right to get cold water with better pressure. There doesn't seem to be a way to sustain both decent pressure and warm water, and at this point, my water heater is maxed, making the water in other faucets scalding. The strange thing about all of this is that if I switch to the tub faucet, there is still plenty of hot water and pressure, so it's not just a hot water volume thing - it seems to be an issue between the water heater and the shower line. Perhaps there's some build up?"

[Dan Mackin]

If it's the type of shower that is started by redirecting the tub water then I would look at the mixing valve. If the tub still gets hot water, but the shower does not then it really narrows down your problem area to somewhere between the mixing valve and shower head.