Have changed heating element, stat, but water still cold

The top thermostat controls your water heater meaning if it is not working you wont have any hot water. If the top t-stat needs to be reset by pushing button in then check the element with POWER OFF and remove wires from element. check ohms should be around 12 to 19 ohms. If ok then reconnect wires and check amps. turn on power and use clamp on meter for amps. 15 to 20 amps should be ok. if not drain heater and pull out element. while you are at it drain all the water and pull lower element. if replaced and you have some hot water then quickly cool or cold then you have a broken dip tube located under the cold side of the supply line. they are cheap and easy to replace. I hope this helps.

Electric water heaters never power BOTH the upper and lower elements at the same time.

If the water in the tank is cold, either the top OR bottom element will be powered through the upper thermostat (t-stat), never both at the same time. The upper t-stat will send power to the upper element until the temperature of the water in the top of the tank reaches the set point of the t-stat say 140 degrees. When the water temperature in the top of the tank reaches 140 degrees, the t-stat is "satisfied" and disconnects the power from the top element and sends it to the lower t-stat.

IF the temperature of the water in the lower half of the tank is lower than the set point of the lower t-stat, the t-stat closes to send power to the lower element. The lower element REMAINS powered by the t-stat until EITHER the water in the lower part of the tank reaches the set point temperature of the lower t-stat again, say 140 degrees; OR the temperature of the water in the upper part of the tank drops, at which point the upper t-stat "calls" and switches the power away from the lower t-stat and sends it to the upper heating element instead. When the top t-stat is satisfied, it switches power back to the lower t-stat. The process will continue back and forth for as long as needed to bring the temperature of the water in both halves of the tank to 140 degrees.

You must wait until the top of the tank is heated - before the lower element will be powered to heat the water.

I hope this helps you understand how the switching happens in these water heaters. Good luck! Please rate my reply. Thank you.

MAY BE THE STAT IS BAD.. TAKE VOLT METER AND CHECK FOR POWER AT THE HEATING ELEMENTS. COULD BE A BAD ELEMENT ,WICH MAY BE A HOME DEPOT PART ABOUT $10.. IF NOT THESE CAN BE KINDA TRICKY TO REPAIR.. GOOD LUCK HOPE I WAS OF HELP..J

The heating element must be shot. There is an adj there, but it is a tiny dial, and I'm not sure about the 30 gal, but most heaters have 2 elements. If yours starts out too hot then runs out, Blame the element, or check the breaker with a meter to make sure you have voltage to both legs of the 220 volt line. Sometimes one will quit there, and leave you half power. Check it out.

Remove upper and lower access panels
in upper access, use voltage tester to test voltage of on the uppermost terminals above the red reset button. should be ~220V between terminals (110 to ground)
If not: breaker off or bad,
If 220V proceed:
Test the two terminals immediately below this reset button should be 220V
If not: reset tripped or bad
If 220V present, proceed.
Turn off breaker to heater.

Use ohm meter or continuity tester.
test resistance across upper element terminals -should be 10 to15 ohms
check between each terminal and ground -should be open circuit .
If not replace element
Repeat for lower element.

test across lower element thermostat should be no resistance when stat turned up so it clicks on.
(To test that lower stat turns off, allow tank to heat up completely before conducting this test) Turn sta temp down so it clicks off then test across stat terminals -should be open circuit

The upper thermostat is a 3 way switch
The simplest way to test it is to turn the power back on turn the upper stat all the way up so it clicks on and use voltage tester across the UPPER element terminals, should be ~220V
Now turn the upper stat down so it clicks off- check upper element should be 0 V between upper element terminals -(Caution ! terminals will still be live 110V to ground)
The upper stat has now sent power to lower stat.
Turn lower stat up so it clicks on, check Voltage across lower element -should be ~220V turn lower stat down so clicks off, should be 0 V across lower element terminals.

NOTE If tank is completely cold the upper stat will not switch off and wont send power to lower stat.
If lower tank is cold lower stat may not click off even when turned down.
normal stat setting is 125 to 130
The hotter you you set the stat, the faster your tank corrodes.

If the lower heating element burns out the upper element will heat the top part of the tank then shutoff. homw depot/lowes etc should carry elements. 1 turn off breaker, remove element access cover (the 2 panels on the front of the heater) test for electricity at the reset button ( uppermost device in upper panel) to make sure power is off. 2 turn off water (I usually turn off the cold water main to stop water cross feeding into hot supply line back into heater) 3 disconnect the 2 wires on the lower element, test with continuity tester. shhould be no continuity between terminals and tank, but around 10 ohms between the 2 terminals. Check the thermostat for continuity if tank is cold thermostat should be closed ie zero ohms across the 2 terminals.
If stat is bad replace stat; disconnect wires push it up out of the spring clip insert new stat reconnect. If element is bad: drain tank. connect garden hose to tank drain valve, open tank drain valve turn water main on to clear rust sediment and get water flowing. Next remove filter screen from a hot water faucet then turn on ( a hot faucet upstairs or higher than tank drain). Now turn water main off, air will now go in through hot faucet and tank will drain, takes about an hour. Use a water heater element wrench about$10 to remove element(s) make sure no bits of rubber gasket are left in element opening- dig em out with a screwdriver if needed. Insert new element with its gasket and tighten. reconnect wires DO NOT TURN ON ELECTRICITY! BE SURE TO FILL WATER HEATER WITH WATER ! Turn water main back on -air will come out of the hot faucet for several minutes. When water runs without any air sputtering, turn off faucet and replace the faucet filter screen. check element(s) for leaks. turn breaker back on.

when you replaced them did you bleed all of air off tank before restoring power to w/h if not you could have burnt the new ones , are you getting 220 volts at top of w/h and ck wiring again to be sure properly wired top comes first and when has reached set point of top t-stat it transfers power to bottom just like a 3-way light switch operates 120 volts always on bottom waiting on the other side of the line to heat the element on 220

There will be no current to bottom element until top element shuts off. then top thermostat will send current to bottom element only after the top half of the water heater has heated up and shuts off current to top element. Only one element at a time can be on. If current still does not go to bottom AFTER top element shuts off, the top stat could be bad.

I have a triton opal shower.

I turn shower on low pressure and cold water. then no low pressure and piping hot water for a very short time then low pressure and cold water.

I've changed the solenoid and the little black plastic ball.

Help !

not familiar with model. element can be inside cabinet in which case it will be obvious or may be in a cylinder heater mounted in the base. suspect stats as well or possibly the module