That’s what it sounds like, but - if this is a new issue, there’s something else. Unless maybe after all these years, this is the first time both showers were in use simultaneously…
We have only owned the house for 5 years, two of which we lived there. We rarely showered at the same time as our kids and this was not something I was aware of. Until having 4 adults in the house, all young women with long hair, it’s never been brought to our attention. They go out together and all get ready at the same time.
They were not so much complaining, (they have rented for 2 years,) just wanting to let us know in case we wanted to address it for the next tenants. Sweet kids and I will miss them.
You can test this if you have a sink faucet that has separate hot and cold valves. Do you get any hot water flow at all? Turn on a downstairs hot valve…you should have some flow, then turn on the upstairs shower…does the hot flow drop much lower?
I just had a thought - back in the dark ages (well something like 40+ years ago) many houses lacked the type of shower valves that adjusted for changes in water pressure with the hot or cold water supply lines. The classic symptom of this is when someone was showering if a toilet was flushed the temperature of the water would suddenly and significantly change.
If you have this situation, replacing the current show value(s) is not hard.
…well something like 40+ years ago) many houses lacked the type of shower valves that adjusted for changes in water pressure with the hot or cold water supply lines. The classic symptom of this is when someone was showering if a toilet was flushed the temperature of the water would suddenly and significantly change.
If you have this situation, replacing the current show value(s) is not hard.
House was built in the 60’s. There is no access panel to the shower mechanism, which certainly implies original plumbing. But would this really be a contributing issue to the downstairs getting no hot water when the upstairs is used?
House was built in the 60’s. There is no access panel to the shower mechanism, which certainly implies original plumbing. But would this really be a contributing issue to the downstairs getting no hot water when the upstairs is used?
Access panels are nice, but not required to change mixing valve systems.
The lack of a pressure compensating valve on down stairs shower likely would contribute to such water temperature changes assuming both showers are running on the same water heater and cold water supply.
Since this valve has mechanical moving parts, the valve could fail. Maybe after 60 years some component has failed - or maybe it is a water heater is causal or maybe the problem has been present since you owned the house and only the specific daily routines of your tenants replicated conditions for the observed symptoms.
We recently remodeled both bathrooms, all new temperature compensating fixtures in the tub/sower, new 1/4 turn valves and so on. Before if one was in the shower and anyone, anywhere opened a spigot or flushed a toile, instant temp change until it was off… Now, even flushing in the same bathroom makes no difference in the temps, maybe a slight lowering of volume, depending on how many other spigots were opened, but the temp remains constant…
My guess… the hot water valve downstairs is suffering from reduced flow (The valve could be failing, or could be debris/scale in the hot water line). When the upstairs hot water tap is opened, hot water flow downstairs is further reduced. The cold water line is not restricted, so water mixes overwhelmingly cold. Tenant perceives this as “upstairs is taking all the hot water”.
The water heater is not the issue - if it was, both locations would lose hot water. This is a delivery/supply/flow issue.
Assuming there are no service valves feeding downstairs that are partially closed/obstructed, the most likely culprit is the mixing valve at the downstairs shower.
The only trigger for the downstairs shower losing hot water is if someone uses the upstairs one at the same time.
How severe is the “No hot water” for the downstairs?
It could be the downstairs shower doesn’t have a (good) pressure-compensating valve and/or has more restrictions in the hot water getting to it. So when you have both running in parallel, not as much HW can go downstairs.
Or it could be a really bad valve/installation downstairs is making it so when pressure drops on the HW side it decreases the HW. (As opposed to decreasing the HW when the pressure drops on the cold side - which would help keep you from getting scalded.)
I suspect the only remedy will be an independent tankless water heater for the downstairs…not that there is room even for that.
I expect that if you turn on just HW at both, you get good HW output at both (for a little while - until the HW runs out because you’ve gone through 80+ gallons of HW)
If that is not the case, you’ve got something really really strange going on.
If that is the case, good valves at both locations should be all that’s needed to get decent HW at both (until the HW runs out)
jeffbrig My guess… the hot water valve downstairs is suffering from reduced flow (The valve could be failing, or could be debris/scale in the hot water line). When the upstairs hot water tap is opened, hot water flow downstairs is further reduced. The cold water line is not restricted, so water mixes overwhelmingly cold. Tenant perceives this as “upstairs is taking all the hot water”.
I vote for the restricted flow theory.
The shower that suffers the lack of hot is either:
On a line that is older, potentially has built up deposits slowing hot water flow;
and/or
Is a smaller pipe. Half inch? 3/8’s inch??? And/or the hogging shower’s line is newer, cleaner, larger.
Also concur with an earlier conclusion on the heater. (i.e. Heater is not the problem.)
When you get this figured out it would be very nice to know what happened. And since there probably will be intervening threads, from my view point a new thread is preferred.
