I serviced a 30a 240v water heater for a home and found on the timer that someone had tied one 120v leg to the line and one 120v to the load on the incoming power, same on the output to the water heater. (has a 240 volt clock). Check voltage at the element before I realized this and it read 240v. I disconnected and bypassed the timer (cutomer didn't want it) still have the 240v of course. The customer said the water heater works a little better but still runs out of hot water too soon. The water heater is brand new and has 2 elements, both reading 12 ohms which is correct. The top element was on but the bottom one wasn't when I left. I know they have thermostatically controlled switches on both elements. So maybe the lower one is not kicking on when its supposed too?
The Golden Rule - "The man with the gold makes the rule"
Either thermostat could be bad or it could be a broken dip tube. Let it warm up until the top stat is satisfied and see if it switches to the bottom stat. Then be sure the bottom stat passes the power to the lower element. If the lower element satisfies the stat and you still run out of hot water too fast suspect the broken dip tube. That will allow the incoming cold water to short circuit the heater and go right out the top. Normally the cold water gets introduced into the bottom and tends to stay there.
Re: Water heaters - electric#63738 03/24/0602:23 AM03/24/0602:23 AM
OK Let me play devils advocate here - Did the customer define " Too Soon" and How big is the water heater ( in gallons). I have a daughter that thinks a 15 minute HOT shower is pushing it ! Where as I can be in and out in less then 5. These all figure in.
Re: Water heaters - electric#63740 03/24/0612:03 PM03/24/0612:03 PM
The dip tube is a pipe that runs from the cold water inlet to the bottom of the tank so the water won't mix. The "hot" outlet pulls water from the top. If you get them swapped and the dip tube pulls from bottom of the tank you won't get much hot water out of it. As an electrician all you really need to prove is that the top stat gets satisfied and the bottom element pulls current after that, until it is satisfied. The rest is just gee whiz info ... unless you like embarassing the plumbers.
Re: Water heaters - electric#63742 03/24/0601:55 PM03/24/0601:55 PM
On water heaters that have both fittings on the top, the dip tube is part of the cold fitting, it directs incoming cold water to the bottom of the tank when hot water is drawn off the top.
I'd check the thermostats.
IIRC, the top element heats until the water in the top half of the heater gets to temperature, then the thermostat throws control to the lower thermostat, which heats the lower water until it reaches temperature, then opens.
Re: Water heaters - electric#63743 03/26/0610:47 AM03/26/0610:47 AM
Does the water heater have a circulating line? If there is no check valve installed you will have the same problem, the cold water goes to the bottom of the tank and right out the circulating line. they are a great item but require the right parts Dave
Re: Water heaters - electric#63744 03/26/0601:10 PM03/26/0601:10 PM
check the plumber's work. The top of the tank has fittings labeled "H" and "C" or hot and cold. Make sure he didn't install it backwards or it will act as gfretwell says and draw very little hot water. Also, check the water temp on the hot side only. See if the t-stat is set to around 120 F. If this is a brand new heater, the dip tube problem has already been corrected. I usually check the elements with an amprobe. The reading is around 18 amps at each element. Only one will work at a time. You can move the t-stat to throw the electric up to the upper element to test it.
Re: Water heaters - electric#63745 03/26/0604:54 PM03/26/0604:54 PM