Okay, the hot water heater is old, and when we replaced the burners last year, the plumber told us that we'd probably have to replace the hot water heater in the next couple years. But the problem we have is, well, odd. The hot water heater is downstairs, and there's no problems down there, but there is upstairs. While I can get plenty of hot water for dishes (though I have to be a little careful), I can't get enough for a shower. It starts hot, but within about a minute or so, it's lukewarm and within two, it's gone. And if someone has taken a shower upstairs, forget getting any hot water from the upstairs bathroom faucet or the kitchen. Frankly, I'd like to put off spending the money on a new hot water heater, especially since the fridge just died and we had to replace that!

Hi Bratling...

You can relax on the water heater for now as I'm pretty sure that is not the issue as you have stated that hot water downstairs is OK, but upstairs hot water isn't!

More likely here, is going to be that a mixing cartridge (balancing spool/stem assembly) at a SINGLE LEVER faucet or shower valve has gone bad and simply needs to be repaired.

Here, the mixing valve that normally keeps hot and cold water separated has failed and is allowing cold water to flow into the hot water and that is what causes the issues you mention.

To check to see if I am correct, you'll need to shut off the HOT WATER valves under any sinks that have single lever faucets and then try the showers and see if everything is back to normal. If the problem resolves then the issue is at one of the single lever faucets and you will need to turn on one hot water valve at a time to determine which one makes the problem reoccur. Here, you would then replace the mixing cartridge to fix that faucet and the problem entirely, right?

If the problem doesn't resolve after shutting the valves under the sinks then the issue could be at the single lever shower valve(s). Here, unless you can isolate the shower hot side (via shutoff) it is usually impossible to confirm the mixing cartridge is the culprit, so you may just want to replace the shower mixing cartridge to eliminate it as a source.

Finally, one other thing to check will be to close off the WASHING MACHINE VALVE (or valves) and then test your faucets/valves. If you find the issue is resolved after you shut off the washing machine shutoff(s), then the washing machine solenoid valve could actually be the culprit causing your issue... ;)

Try this stuff or call in a plumber to quickly resolve all this for you, OK?

Good luck!

Mark

Thanks! We'll try it to see!