1960s house with 2 showers. Just replaced the 55gal electric hot water tank elements, and there is hot water in all of the faucets, showers.
However one of the showers only runs lukewarm. Obviously there is an issue with that shower’s mixing valve. But, this lukewarm shower takes/uses all of the hot water. So, if someone has a lukewarm shower, the hot shower has no more hot water.
It is a small hot water tank, so back when both showers were not it was not unusual for this to happen. But now that barely any hot water is coming out of the lukewarm shower, it’s a mystery where all that hot water has gone.
Checked for leaks and can’t see any in the hot water supply. Checked the hot water tank and it’s working. So where is all the hot water going if the shower is lukewarm? Next step, after looking at the mixing valve is to put a low-flow head on that shower and see if it’s just the sheer volume of cold water overwhelming the hot water and making it feel lukewarm while simultaneously putting all the hot water down the drain.