New guy needs help with water heater!

[fold_em83]

Hey guys, I'm new here so thanks for helping me out. My wife and I just bought our first house in November. I feel I have an above average knowledge of home maintenance and repair but this has me puzzled. My problem is that when you take a shower the hot water only lasts for 10 to 15 minutes. We have a 50 gallon water heater that appears to be relatively new. I have replaced both elements but the ones that came out of it looked fine. The thermostats were set as low as they go so I turned them up a little. Both elements are getting hot. All of the pipes are copper and they are all exposed to the basement. The shower is the farthest point from the hot water heater. I have gone to the basement while the shower is running and felt the hot water pipe supplying the shower. The entire length of the pipe is warm to the touch. The most puzzling part about all of this is that when the water in the shower runs out, the bathroom sink will also be cold but the kitchen sink, which is the closest to the hot water heater, will have very hot water. I have traced all of the pipes in the basement and I can't find anything that would be causing this. Can anybody help?

[HayZee518]

in a hot water tank the heated water stratifies to the top of the tank. the dip tube goes down to the bottom so the bottom element is supposed to turn on first. re-adjust your tank thermostats so the bottom one comes on first then the top one.

[fold_em83]

So I should just set the lower thermostat to a higher temperature than the upper one?

[davidg73]

no you set the lower to a lower temp, if you have the top set to 140, set teh bottom to 130-135.

BTW, since you have access to teh pipes you may want to insulate them as much as possible. i have this same issue in my house and it is due to teh water cooling in the pipe before it gets to teh master bath. if i leave a sink or the tub diverter partially running, i have all the hot water i need. if i run only the shower, the lower flow rate results in no hot water after a few minutes while all other fixtures still get hot. i cannot do anything about mine since i am slab on grade with underground pipes, but since you have basement access you can.

[fold_em83]

I turned both thermostats up last night and it was better. They are both set at the same setting which I think is setting C. It is one less than the hottest possible setting. I was going to insulate all of the pipes as well, I just haven't done it yet.

[HayZee518]

Another possibility is if your house has a WHOLE HOUSE WATER TEMPERING VALVE. What this does is mix cold water with the hot water' heater's output to prevent scalding at ANY of the houses hot water taps. Used to be a tempering valve right at the shower valve.

[fold_em83]

I've already checked for a tempering valve and can't find one. I think I'm going to be replacing the water heater soon.

[jnaas2]

Check to see if the water lines are reversed, Ive seen them hooked up backwards. The cold always goes the right side of the tank with the thermostat covers facing you. There is a dip tube inside the water heater on the cold water inlet side that directs all incoming cold water to the bottom of the tank, since heat rises the hot water stays above the cold water. I have also seen some where the tube was removed and some water heaters had a recall on the tubes because they were breaking down and dissolving. One other thing to check is if one heating element or thermostat is bad. you can remove the wires from the element and check it with a ohm meter or continuity tester, if it shows infinite resistance the element is shot. Most water heaters only heat one element at a time the upper element heats first when that thermostat is satisfied it will then start the bottom element. Last thing if the water heater is full of calcium deposits it will cut way down on hot water capacity, the lower element is usually yhe bad element because of calcium buildup