Hot water running out too soon

Old 01-24-06, 10:05 AM
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Hot water running out too soon

I have a 65 gallon electric hot water heater. I don't know its age since I moved in to the house 3 years ago. When I shower, I need to keep turning the hot water control up until I hit the maximum hot position, then it starts to cool in 15 minutes or so. I tested the output using a bucket at the tub faucet, and it seems to have only about 15 gallons of good hot output, then it starts to cool. It should have about 2/3 x 65 gallons, or 43 gallons, according to a plumber I consulted.

Since I am getting some hot water, the top heating element must be OK, according to the plumber. So, do I need to check the bottom heating element? Could another possible cause be in the hot/cold water faucet control itself? It is a round knob that you turn counter clockwise to open. One knob is used to control tghe output of both hot and cold water. It must be opened almost all the way, i.e, rotated almost fully counter clockwise, to provide hot water. Could it be that this mechanism needs to be adjusted because it somehow is set to provide a mixture of cold and hot water even when it is fully open? So maybe I should take it apart and see how it works and if it can be set to provide more hot water at less of an "open" position? Thanks for any help you can provide.

Jim G.
Old 01-24-06, 10:19 AM
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jagbest, Welcome to the DIY Forums.
It could be a few things. Bottom element as you mentioned. The bottom does not come on until water is used. Have you checked other fixtures (sinks etc) after the hot in the shower runs out? This would/could tell you if it is the shower valve. Another possibility is the dip tube is bad. This is located under the inlet (cold) supply pipe. It just sits there so is easily removed after the pipe is disassembled. The dip tube takes the cold water to the bottom of the tank and pushes the hot water out of the outlet piping. Most single handle faucets have a cartridge in them. You may have a bad washer or "O" ring in the cartridge. If you remove it, make sure you mark the top so you reinstall it in the same orientation or it will not work properly. Just some things to check. Good luck.
Old 01-24-06, 03:44 PM
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Chances of a problem in the shower valve causing this are slim to non-existant. It's almost certainly a problem with the WH.

Lower element, upper or lower thermostat, or the dip tube. Any one of them will cause the problem that you are describing.

Start by checking the lower element. Shut the power to the WH off, remove the lower thermostat cover, remove both wires from the element and use an ohmeter to check its resistance. You should get a reading of about 100 to 1,000 ohms. If you get an infinite reading (no continuity), replace the lower element. Drain the WH, then unthread the old one and install a new one. Refill the WH COMPLETELY -- open the tub valve to full hot and wait until you have a solid stream of water coming out of it -- then turn the power to the WH back on.

If the resistance of the lower element checks out fine, then you need to do a voltage check to see if the lower thermostat is turning on, or if the upper thermostat is even sending voltage to the lower thermostat. That's done via a voltage check, with the thermostat covers removed. BE CAREFUL!!

Start with the resistance check of the lower element. If that checks out OK, reply to this post and one of us can walk you through the voltage check.

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