HOT WATER MYSTERY

[MossRoad]

Go around your house and close all the shut offs on each of your fixtures in kitchen, baths, laundry, sinks, etc... and then try them one at a time. That could isolate the problem fairly simply, just takes time.

 

[MossRoad]

Do you have a recirculating pump? There may also be a mixing valve some where.

This too. :thumbsup:

 

[orezok]

Just guessing on my part but don't water heaters have an internal tube on the inlet (cold) side down to the bottom of the tank and the hot water is drawn off the top of the tank ? I think I've heard of these tubes either rotting away or falling off inside the tank and causing a similar situation but I'm getting older and my mind isn't quite as sharp as it used to be. Anyone else know what I'm talking about ?

It is called the dip tube.

Troubleshoot and replace water heater dip tubes

 

[Thomas]

Mixing valve open or gone bad maybe.

 

[LittleBill21]

sounds like a failed dip tube.

Troubleshoot and replace water heater dip tubes

 

[JPRambo]

The lower heating element is shot. the upper element is only a maintainer element. maybe the lower element reset button popped. try resetting button.

 

[fried1765]

Wow!
3 really GOOD ideas!

1st.....I will try isolating each single point faucet, though the shower one may be difficult.

2nd......I will try to remove and inspect the dip tube.

3rd......I will replace the toilet mix valve.

Thanks guys, for three GREAT troubleshooting suggestions.

 

[RickB]

Is it possible that a 3 point cartridge could fail internally to allow this to happen?
Which cartridge.....I have 3 of them.
If one cartridge failed internally, would it affect the supply to the hot side of the other two?
Could a failed toilet mix valve be the problem?
This is all not good!

It's none of the three valves you can control manually. If it were one of them you couldn't get straight cold from the failed one. It's a washing machine, dishwasher or other fixture where the water can mix if something fails. Cut one or both supplies to each one at a time and test.

Lower element failure should give you more hot water than you are reporting. A dip tube failure is a real possibility.

 

[fried1765]

The lower heating element is shot. the upper element is only a maintainer element. maybe the lower element reset button popped. try resetting button.

Removed and inspected both elements at the beginning of this diagnostic process.
Both elements have normal continuity.
When I drained the heater to remove the elements, the water was plenty hot!

 

[fried1765]

It's none of the three valves you can control manually. If it were one of them you couldn't get straight cold from the failed one. It's a washing machine, dishwasher or other fixture where the water can mix if something fails. Cut one or both supplies to each one at a time and test.

Lower element failure should give you more hot water than you are reporting. A dip tube failure is a real possibility.

Considering the symptoms......hot water initially, but quickly only warm water, dip tube failure does seem to make the most sense.
I will check it out......my second option.
Thanks!