Newbie and plumbing illiterate here - We have a ranch house. The gas hot water tank (50 g) is new, in the basement. There is a bathroom w shower right next to the tank area. The master shower is on the main floor, above this. When anyone is in the basement shower, we have no hot water in the shower upstairs. Most of the basement is finished. Our plumber says there is no fix. I refuse to believe that. Thoughts? Thanks!

One thought is that while we may agree with you, there is NO WAY we can diagnose your problem without being there.

way too many variables here.

what size is the piping feeding the HW tank?
what size is the piping leaving the HW tank?
how many gallon per minute is the basemant shower head?
how many gallon per minute is the first floor shower head?
do either, neither or both the showers have scald protection via an internal mechanism?
when the water is not hot on the first floor is there any hot water at any of the sinks?

i'm assuming that if the first floor shower is nice and hot and someone turns on the basement shower that the hot upstairs goes away but when the basement is shut, the hot comes back?
lastly, is the water pressure in the house adequate?

Thanks for trying to help me with this. The inlet and outlet piping from the tank are the same size, ~ 2 7/8" circumference when I measure the outside. We have some hot water if we turn the u/s shower all the way on for the first few minutes the d/s shower is on, but u/s has to be at max. Both have anti-scald, both have 2.5 gpm heads. The u/s taps still have hot water even when the shower doesn't. The house water pressure is more than adequate. If the u/s shower is on & the d/s is turned on, the hot water rapidly (but not immediately) decreases over a few min, then if d/s is turned off, u/s will rapidly go back to normal.



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Replace cartridge in upstairs shower