Why no hot water available for a full bath from 50 gal tank when no hot water used in previous 8 hours?

Answer 1

lots of reasons now it all depends on the type of tank

electric first

if you have a leak like previously posted you will never keep the tank hot but, you will notice your electricity bill has almost tripled

the bottom element may have gone so only the top 11" of the tank is heating
or
the thermostat is not "flip flopping" the top thermostat opperates the power to the bottom thermostat once the top part has reached temperature.
or the bottom thermostat is broken or set too low or
or the dip tube on the cold water inlet that directs water to the bottom of the tank has perished and the water is short cycling to the hot side
or
the bottom of the tank is full of hard water deposits (calcium) and this has reached the bottom element

Gas
new hot water tanks have an energy save built into them. i tried to find the link but couldnt i got it from giant since i am an installer
if no water has been used for a long period of time the tank automatically goes into vacation mode ie barely heats the water, once the sensor feels a sudden change in temperature it starts the tank burner and resumes at it previous setting
or
the dip tube on the cold water inlet that directs water to the bottom of the tank has perished and the water is short cycling to the hot side
or
the gas valve has a faulty thermostat or sensor
or
the sensor has a hard water build up on it and this acts like an insulator so the tank thermostat is not reading the correct temperature.
it doesnt sound like the pilot is out as you still have some hot water just not enough.
these are things you can check yourself if you are handy some might be more complicated and require you call a plumber especially when your dealing with the gas valve and the gas sensors which is attatched to the gas valve.

other stupid things to try
check voltage on leads of tank if it requires 220 make sure one breaker hasnt tripped or failed.
if you have extra long runs of piping and a re circ. system make sure pipes are insulated.
if it is also connected to the underfloor heating make sure that this isnt running when it doesnt need to be.

good luck with this if you get stuck call a plumber tell him what you have checked and what you havent and they should be able to make a diagnosis from there

Answer 2

This happened to my mom. She also started growing weird flower weeds in the back yard. Turned out the water heater had a leak and it ran underground, so the thing was constantly running and didn't have time to get warm. She needed a new pipe and valve. It was expensive.

Answer 3

YOU UNDOUBTABLY HAVE AN ELECTRIC W/H AND THE PROBABILITY IS ABOUT99% THAT THE BOTTOM ELEMENT IS BURNED OUT BECAUSE IT IS BURIED IN THE HARD WATER SCALE IN THE BOTTOM OF THE TANK. WHEN IT CAME ON IT WAS BURIED AND COULD NOT GET COOLED BY THE WATER SO IT OVERHEATED AND BURNED IN TWO.

Answer 4

no hot water or just not enough hot water?

not enough = is it an older tank? maybe it's full of sediment.

Answer 5

Elements are bad. Drain, check and replace. Assuming it is electric.

Answer 6

Pilot light is out.