Strange things happening with my water situation:

I just replaced my hot water heater, and I am certain that it is wired and plumbed correctly. Now I have hot water in my tank, but I only get warm water at any shower or sink in my house. In one bathroom, closest to the heater, I can get hot water if I turn on the sink in the bathroom(hot) simultaneously. This trick also works with my kitchen sink which is very close proximity to the water heater. I can only get warm water at best in my other bathroom, including sinks and tub (farthest fixtures from heater). Oh yes, in the close bathroom, I haven't figured out what combo of faucets will allow me to get Hot water in the sink, I still only get warm. Recap: Hot water in shower closest to water heater and kitchen sink, but only when a different sink is running on hot. Now I have plenty of pressure and volume in every fixture in my house, and when I get Hot out of one of the two that actually work the others are cold. If you turn on any given fixture alone you just get warm with the Hot valve opened completely. All of my fixtures are Moen single knob units.

Any help will be greatly appreciated, because this is the strangest thing that I have ever encountered.

It sounds like you may have a crossed connection, allowing the cold to bleed with the hot. Who did the install?

Was the cold water inlet pipe connected to the proper inlet on the water heater??? It is marked cold and hot on the top of the water heater where the piping connects. It sounds to me like they are reversed.
Either that or the dip tube is bad. This tube takes the cold water down to the bottom of the tank and is inside the cold water inlet.

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Retired after 50 years of plumbing and heating.



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I dd the install, and I am 100% certain that it is plumbed correctly.

It is possible that the dip tube is bad, but it is a brand new unit, maybe any other suggestions. I do greatly appreciate the depots. Thanks

Is there a "circulation line" connected to the heater? And if so, does it have a functioning check valve in the line. Your symptoms would be consistent with a missing or defective check valve. Are these symptoms why you replaced the water heater in the first place?

Sorry I forgot to mention it before. There is no circulation system in place. My old unit was 17 years old, and I had just replaced the lower element andboth thermostats. After all this I had hot water in the tank, but I just could't get it through the lines.

I would start looking at your faucets. Sounds like the cold is getting into the hot side somewhere.

I recently had a very similar situation occur on a jobsite. There was strange temperature fluctuation throughout the house. It appeared that there was a cross connection between hot and cold. I traced out all the piping and could find nothing piped in correctly. I traced the cross connection to the kitchen area and found that the kitchen faucet was allowing a cross connection when the faucet was turned off. The faucet was not leaking, not even a drip. I turned off both supplies to the kitchen faucet and the cross connection stopped. This was a Moen single handle faucet. I replaced the cartridge and solved the problem.

I have tried turning off all faucets individually to try and track down the culprit. No luck! Bah!!! I haven't tried the showers, because I don't know how to cut off their supply without turning off the main water to the house. ( any suggestions for that) All fixtures are moen single acryllic knobs with the exception of the kitchen sink. It is stainless single lever Moen.

Also my washing machine has two seperate lines, as it should, with no "Y" connector. I haven't checked the dishwasher, because I am uncertain as to how to pull it out. I have it out a little, but I didn't want to risk damage due to uncertainty.

Thanks,



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You may have one of those problems which is being caused by something unique to your system, and only a plumber at the site can diagnose and cure it.

It is possible the tub/shower valves could cause the problem, but if so, turning them to the fully hot side should stop the problem. If that does cure it, then you need new cartridges in the valve(s).

First of all, Thank you to everyone that replied. I did indeed call a plumber, only to find out whoever plumbed my house originally tied a hot and cold line together. Yeah me!!! Now I have to spend some serious $ to fix someone else's mistake. However I do want to say Thank you for all of your suggestions.

That is not a new "mistake" so it should have had nothing to do with the installation of the new water heater. In other words, you should ALWAYS have had the problem, which would be why I asked if you had it before you replaced the water heater.

I found your post and am having the same issue after having a new water heater replaced on Tuesday. Old water heater was working fine but was 22 years old so figured we would be proactive. Same thing is happening, but as someone stated if the lines were crossed before whey would the problem kick in now, and not in the last 8 years we've lived here using the working old heater. Would love to hear how you solved the problem, Thanks!!!

Having the exact same problem but only really after having installed a new faucet (with thermostat) in the bathroom. Only "hot" shower water when faucet for hot water in kitchen is opened.