State select water heater runs out of hot water in 15 minutes

[Snap Cutter]

I have a state select gas water heater that is three years old and has a mixing valve and expansion tank. the problem is that in just the last couple of days this person went from taking a 30 minute shower to not even being able to last 15 minutes . i took the temperature at the tub spout and it started at 130 and with in 15 minutes it was 100 . so I thought the mixing valve was bad until I felt the hot feed pipe going in to the mixing valve and that was cold. so I opened drain and that was also cold,also I did not notice any sediment when I opened drain. could it be the dip tube ?

 

[Reach4]

could it be the dip tube ?

Yes.

 

[Sponsor]

 

[Gary Swart]

The dip tube would be the first thing to check. The symptoms do sound like that may well be the problem. Quick and easy to check and fix if necessary. The dip tube hangs in the cold water intake. Just disconnect the intake and use your pinkie finger to lift it out. If it is broken, buy a new one. May have to shorten the new one a little, they are often a tad long. I should good almost to the bottom of the tank, exact measurement not necessary.

 

[Dj2]

Does this happen every shower, including the first shower of the day?

You have a small glass window under the gas valve. Look inside and see if your burner shuts down without touching the thermostat, when a large volume of hot water leaves the tank.

Please report back.

 

[Jadnashua]

See if the burner is actually turning on once you draw off some hot water.

Did they change the shower head? Going from a low-flow one to either a modified one, or an unrestricted one could easily empty a WH within 15-minutes.

Is there anything new in the house that uses gas? Could the burner be starved for gas? Do all of the other gas appliances work properly including furnace?