Heater trips off before reached heat limit - Jacuzzi RapidHeat In-Line Heater U395000 [ Bathtubs and Whirlpools,

If you have already descaled your Tempra 24 Tankless water heater and replaced the flow sensor, but the high limit switch is still tripping, there could be a few other possible causes of the issue: Malfunctioning thermostat: A malfunctioning thermostat may cause the heating modules to overheat, which can trip the high limit switch. You may need to replace the thermostat if this is the case. Insufficient water flow: The Tempra 24 Tankless water heater requires a minimum flow rate of 0.5 gallons per minute to operate properly. If the flow rate is too low, the heating modules may overheat and trip the high limit switch. Check the water flow rate to ensure it meets the minimum requirement. Electrical issues: If the wiring or electrical connections are faulty, it may cause the heating modules to overheat and trip the high limit switch. You may need to inspect the wiring and connections to ensure they are intact and properly connected. If none of the above solutions work, it may be best to contact a professional technician for further diagnosis and repair. It is unlikely that you would need to replace the entire unit if the issue is isolated to a single heating module.

Why Does My Electric Water Heater Reset Button Keep Tripping? So the red reset button on your electric water heater keeps popping out and needing to be reset.
Here's the most likely problem: The water in your water heater is getting too hot.
When the water temperature in your water heater exceeds 180°, the red reset button (also known as the high-limit switch) trips. This tripping protects you from getting scalded or burned when using hot water in your home.
OK, but then what's causing the water in your water heater to get so hot? The most likely cause is a bad thermostat.
How a bad thermostat causes your water heater reset button to trip Electric water heaters have a lower and upper thermostat-one for each heating element.
The thermostats are responsible for controlling the heating elements. When the water has cooled off, the thermostats kick on the heating elements to heat the water. And once the water has reached your desired temperature, the thermostats shut off the heating element.
(This is very similar to the way your heating and air conditioning thermostat controls your home HVAC system.)
But these thermostats can go bad. When they do, they sometimes get stuck in the "on" position. This means that that the heating element continues to heat your water, eventually causing the high-limit switch to trip.
The fix: The bad thermostat needs to be replaced. A plumber can use a multimeter to test the thermostats and find out which one is bad.
Other problems that can cause your high-limit switch to trip While a bad thermostat is the most common reason your water heater's reset button may trip, it's not the only one. Other common causes include:

• A shorted heating element-It may be that the thermostat is working just fine and shutting off the heating element. But a short in the element is causing it to continue to heat your water.
• Loose wiring-A loose wire in the water heater can generate heat that can cause the high-limit switch to trip.
• Bad high-limit switch-The switch itself may be malfunctioning and tripping when it shouldn't be.

Get a professional plumber's help

Do you live in the Minneapolis-St. Paul area and need a reliable plumber to help you troubleshoot your water heater problem? Contact MSP Plumbing. We can usually fix the problem the same day.

The error code is HL, not hi
This is telling you the high limit switch is tripping(safety feature)
Lack of flow, corroded heat exchanger, bad high limit switch, bad thermal regulator.....
Take these steps to try and get it narrowed down.
With heater off
Locate the high limit switch, unplug the two wires connected to it, put a jumper wire in between those two wires. Turn on the heater, if it fires you need to wait till it heats all the way up. If if heats up with no fault in the cycle then most likely it's a bad high limit switch, if it continues to trip then thermal regulator, it may need both parts.
If it doesn't fire at all then you will probably need a professional

Hi there!
Check the rating of the electrical circuit breaker where the unit is tapped, it must be at least 25 % higher than the unit' s current rating on nameplate to avoid tripping.
If hi-limit of the unit trips after reaching temperature setting, try lowering the set point; hi-limits are designed to trip off at 450F for safety. Or it may be faulty causing premature or early trip off temperature.
Regards.

Wash water
temperature T3 in
wash block CHDESIN
not reached
within 60 minutes
Temperature limiter F2 has
cut out
Reset temperature limiter F2. See
Resetting Temperature Limiter F2
(Thermostat), 030 4.2. If necessary,
replace the temperature limiter. See
Replacing Temperature Limiter F2
(Thermostat), 030 4.3.
Heater elements do not heat
up
Check heater elements. If necessary,
replace a faulty heater element; see
Heater Element Replacement, 030 4.5..
Heater level switch does not
switch
See Heating Level Switch Does Not
Switch On, 050 3.1
Voltage (6VDC) from the
electronic not present. The
heating level switch controls
the heating relay voltage.
Check plug connections.
Check electronic module output voltage;
see 070 Fig. 5, Pos. 9.

Hi there!
Reset button of hi-limit switch will only pop-out when its sensing bulb sensed temperature higher tha 450F (trip temperature of hi-limit). Theramostat may be bad allowing oil to reach temp above 450F causing hi-limit to trip-off or hi-limit itself is bad tripping-off at temperature lower than 450F.
Check also the position of the sensing bulb of the hi-limit, it may be positioned touching the heat tube (for gas fryer) or heating element (for electric fryer) that's why it prematurely trips-off.
Regards.

Hi limit device trips prematurely (should only trip when oil temp reaches 450F). Check if the hi limit sensing bulb (located inside the fryer tank, between fire tubes) is not touching the fire tube because if it does, it will sense the heat from burner flame which is much higher than oil temp.

You could tripping the high temp limit this will be located near the heat exchanger When it shuts how long does the blower motor stay running? Do you have a meter?

I would say you have a bad element in the bottom.If the water is cold and heat until the top thermostat reach it tempture,then switch the bottom element and then the breaker trip.So replace the bottom element.

i have replaced TH2 in my dle0322 about 6 times now. It never lasts more than a month. What could be causing this?