Please Help - Our Water Heater Is Possessed!

[sheandhe]

Hello Forum Members -

About a week ago our hot water heater stopped heating water, or at least heating it to an acceptable temperature. It was in our home when we purchased it ten years ago. We replaced the thermo couple and cranked the thermostat all the way to HOT. All we got was lukewarm water - same as before. It wasn't until two nights ago that we noticed while taking a lukewarm shower that if the bathroom faucet or the kitchen faucet is in use while the shower is running the water becomes hot and we can can somewhat regulate the hot water by turning either the kitchen or bathroom faucet to either full blast or a trickle.

Any idea what is going on? Any insight and advice would be appreciated.

Thanks in advance,

Gemma and Murray

 

[Jadnashua]

From what you've said, the WH IS working, and you either have a distribution problem or a fixture problem. Is the only fixture that can't get hot the shower? What about other things in the house? What kind of shower control valve is it? Do you know if it is a thermostatically controlled valve, a pressure balanced valve, or an old, basic valve?

Do you have a recirculation system? Have you changed any faucets recently? If you say shut the water off to the kitchen sink at the shutoffs in the cabinet, does it get better? What about doing the same thing for the vanity(s) in the bathroom(s)? Some single handle valves when they fail internally can cause the hot/cold to cross-over. You may have that situation. If so, then finding the offending one is the next task. Repairing or replacing that one will solve your problem.

 

[Sponsor]

 

[sheandhe]

Jim,

Wow! Thanks so much for your reply Jim.

Okay, it's a plain old valve for the shower. We haven't changed any faucets or water lines. None of the fixtures gets really hot water without two of them being in use at the same time. Hmmm. Yes, it certainly does seem like our water heater is working!

Okay, so it looks like we should try shutting off the water for the sinks at their respective valves. We'll try it.

 

[Jadnashua]

The only ones that can cross-over are single handle ones. ANy older, two handle faucets can't (normally, anyway) cross over without something else going wrong, too.

 

[hj]

A recirculation system with a bad check valve will do exactly what you describe.