Stiebel Eltron Water Heater Keeps Tripping [7 Reasons To Fix]

It can be very inconvenient and disruptive to your daily routines if the water heater keeps tripping and you have to fix it. Unless you find out the root cause of it, you can solve the issue permanently. 

Why is the Stiebel Eltron water heater keeps tripping? There are some common reasons behind that. Which includes – 

  • Excessive power supply
  • Clogged heat exchanger
  • Burnt-up heating element
  • Malfunctioning flow sensor
  • Worn-out element

There are some other reasons as well. A malfunctioning thermostat and faulty control board can also cause this issue in some cases. 

There are some common solutions to the Stiebel Eltron water heater problems. For excessive power supply problems, consider changing the breaker size. For the heating element problem, you have to clean or fix it. 

Depending on the reasons, the solutions are also different. So, keep reading the whole article and get rid of this tripping problem permanently. 

Stiebel Eltron Water Heater Keeps Tripping: Quick Guide!

There are several reasons why the Stiebel Eltron water heater keeps tripping. Here is a quick overview of these reasons with their appropriate solutions. 

Excessive Power SupplyCheck the recommended circuit breaker size and replace any breaker larger than the recommended size.
Clogged Heat ExchangerDescale the water heater 
Burnt-Up Heating ElementAlways turn off the system and water supply together when not requiring hot water.
Malfunctioning Flow SensorReplace the flow sensor
Worn-out Heating ElementCheck the heating elements with a multimeter and replace any faulty ones.
Malfunctioning ThermostatReplace the faulty thermostat with the help of a professional or consult a dealer.
Faulty Control BoardHave the control board checked and repaired by a professional.
stiebel eltron water heater keeps tripping

Stiebel Eltron Water Heater Keeps Tripping: Detailed Overview 

Here are the reasons behind the continuous water heater tripping problem in detail. Detailed solutions are also given for your convenience. 

Reason 1: Excessive Power Supply 

Every Stiebel water heater has a different power input requirement. If the power supply to the tankless unit is more than recommended, it can cause a power overload to the heater system. As a result, the Stiebel water heater will keep tripping.

How to Fix it:

Check the breaker size number for your water heater and match it with the recommended circuit breaker size. Here are the recommended circuit breaker size and maximum load capacity for some Stiebel Elton models. 

Tempra Trend (Models)Number & Min Circuit Breakers SizeMax. amp. load
Tempra 121 x 50 A1 x 50A-1 x 44A
Tempra 36 Plus3 x 50 A3 x 50A-3 x 44A
Tempra 202 x 40A-2 x 35A2 x 40A-2 x 35A
Tempra 24 Plus2 x 50 A2 x 50A-2 x 44A
Tempra 152 x 30 A2 x 30A- 2 x 26A
Tempra 29 Plus3 x 40A-3 x 35A3 x 40A-3 x 35A

If you are using a breaker bigger than the recommended size, replace it immediately.

Reason 2: Clogged Heat Exchanger

Due to the minerals in the water, scale, and sediments keep accumulating on the heat exchanger over time. As a result, the heat exchanger has to work overtime to make the water hot enough and get overheated. it causes the Stiebel Elton water heater to trip.

How to Fix it:

You have to descale the water heater to get rid of this problem. It is recommended to descale the tankless water heater at least twice a year depending on the water hardness. 

If you haven’t descaled your water heater for more than six months, there is a possibility that a clogged heat exchanger is causing the tripping problem. 

Here’s how to descale the heat exchanger of the Stiebel Elton water heater.

Step 1: Begin by turning off the power supply to the water heater. Locate the breaker or power switch for the water heater and switch it off. This is important for safety purposes.

Step 2: After that, shut off the water supply to the water heater by closing the isolation valves located on the inlet and outlet pipes. This will prevent water from flowing into the heater during the descaling process.

Step 3: Prepare a bucket filled with vinegar. Vinegar acts as a descaling agent to remove mineral deposits from the water heater’s elements. Make sure you have enough vinegar to fill the bucket and submerge the pump.

Step 4: Once the vinegar is prepared, connect a small fountain pump or pond pump to the water heater. Use inexpensive washer-dryer hookup lines to connect the pump to the hot and cold outlets of the water heater. This setup allows the vinegar to circulate through the system.

connect the pump to the hot and cold outlets of the stiebel eltron water heater

Step 5: Plug in the pump to start the circulation process. The vinegar will flow from the bucket into the water heater, through the pump, and back into the bucket. Let the circulation continue for about 20 to 30 minutes. This allows the vinegar to dissolve and remove mineral deposits.

Step 6: While the descaling process is underway, inspect the connections and fittings for any leaks. Address any leaks promptly to ensure a tight seal.

Step 7: After the recommended descaling time has elapsed, turn off the pump and disconnect it from the water heater.

Step 8: Now, drain the vinegar from the water heater by opening the isolation valves and allowing the vinegar to flow into a separate container or bucket. Ensure that all the vinegar is drained from the water heater.

Step 9: Once the vinegar has been drained, close the isolation valves again to prepare for the next steps.

Step 10: Replace the anti-scale cartridge if your Stiebel Eltron water heater has one. Follow the manufacturer’s instructions for replacing the cartridge and ensure it is properly seated and secured.

anti-scale cartridge of stiebel eltron water heater

Step 11: Open the isolation valve on the cold water supply line to allow water to flow into the water heater. Check for any leaks and ensure the valve is fully open.

Step 12: Now, open the isolation valve on the hot water outlet line in a similar way. Again, check for leaks and ensure the valve is fully open.

Step 13: Switch the power to the water heater by turning on the breaker or power switch. Make sure the temperature selector is set to the highest setting initially.

Step 14: Calibrate the water heater’s temperature selector by turning it all the way to the highest setting and then back to zero. This step ensures accurate temperature control.

Step 15: Set the desired temperature for your water heater. Adjust the temperature selector to your preferred setting. A common recommendation is around 109 degrees Fahrenheit for an ample supply of hot water.

Step 16: Double-check all connections and valves for leaks once the water heater is operational again. Address any leaks promptly to avoid water damage and maintain efficient operation.

Reason 3: Burnt-Up Heating Element 

Sometimes you may forget to turn off the heating system even after turning off the water supply. In this case, the heating element will try to heat the system even if there is no water. 

As a result, it gets overheated and the water heater keeps tripping. This is a common occurrence.

How to Fix it:

Always turn off the system and water supply together when you don’t require hot water.

Reason 4: Malfunctioning Flow Sensor

The flow sensor of your water heater can be clogged or faulty sometimes. In this case, it can not sense if there is water to heat or not. 

Sometimes, the water heater can continue to heat the water without proper flow detection. This can lead to overheating and cause the heater to keep tripping.  

How to Fix it:

First, you have to check if the flow sensor is working properly or not. If not, you have to replace it. There are three reasons why a flow sensor can stop working. 

  • The flow sensor is clogged
  • The O-ring is damaged
  • The flow sensor is broken or worn out

Here’s a link to an article on how to identify a faulty water flow sensor in Stiebel Eltron and replace it in detail. You can click on it if you want to know about the symptoms of a faulty flow sensor with a replacement process.

Well, let’s learn how to replace the flow sensor-

Step 1: Safety first! Turn off the power supply to the water heater. Turn off the water supply as well.  

Step 2: Turn a hot water faucet on in your house to drain the water heater. 

Step 3: The flow sensor is located on the access panel in your Stiebel Eltron. Open the access panel to access the sensor. 

wiring connection from the flow sensor of stiebel eltron water heater

Step 4: Disconnect the wiring connection from the flow sensor. 

Step 5: Now, remove the tiny retaining pin for the top of the sensor that holds the flow sensor in place.

Step 6: Take an adjustable wrench and unscrew the securing nuts from the flow sensor. 

Step 7: Lift the entire assembly where the flow sensor is located. This will cause the flow sensor to rise as well. Hold onto the sensor and wiggle it out of its position until it is removed.

Step 8: Wiggle the flow sensor out of its place. 

Step 9: Carefully check the flow sensor for buildup and dirt. If you find the sensor to be clogged or dirty, blow some air compressor to clean it. Check the o-ring that keeps the flow sensor in place, if this is worn out, you have to remove it and place a new o-ring beneath the sensor. Check the flow sensor as well. If it looks damaged, excessively clogged, or worn out you have to replace it. 

Step 10: Now you have to Install the new or clean flow sensor. Align the new flow sensor and insert it back into its original position. You might have to wiggle it a little bit and apply slight force to fit it properly. 

Step 11: Reconnect the wiring connections to the sensor. 

Step 12: Restore the power and water supply. 

Reason 5: Worn-out Element 

The heating elements of your Stiebel Eltron water heater can wear out over time. As a result, it starts malfunctioning. Either the element overheats or underheats the water. When the element overheats, the Stieble Eltron water heater keeps tripping. 

How to Fix it:

You have to check the element with a multimeter and if found faulty, you have to replace it. Here’s what you need to do. 

Step 1: Before beginning the process, disconnect the water heater from the power supply. Turn off the water supply as well. 

Step 2: To check the resistance of each element, use an Ohm meter. Consult the heater’s nameplate and wattage specifications to find the correct resistance values.

Step 3: Take the Ohm meter and measure the resistance of each element. Touch the meter’s probes to the terminals of an element. If the meter reads 0 Ohms or flickers, it indicates that the element is faulty and needs to be replaced.

Step 4: To replace the element, take a Phillips screwdriver to disconnect the wire connected to the faulty element. If there are multiple failed elements, it’s helpful to mark the wires associated with each one to avoid confusion later.

Step 5: Next, close the ball valves and drain the water heater. Locate the ball valves on the water heater and turn them off. 

Step 6: Then, connect a hose to the drain valve and direct the other end to a suitable drainage area. Open the drain valve and let the water heater drain completely.

Step 7: Once the water heater is drained, you’ll need an 11/2˝ socket wrench spanner to remove the failed element from the heat exchanger socket. Carefully unscrew the faulty element, taking note of any signs of internal damage such as splitting caused by air contamination during heating.

Step 8: Take the new element and ensure that it has a factory-provided O-ring in place. Insert the new element into the heat exchanger socket, making sure it fits securely.

Step 9: Use the 11/2 ̋ socket wrench spanner to tighten the new element. Be careful not to over-tighten it, as this can damage the O-ring seal. Just ensure it’s securely fastened.

With all the heating elements replaced, it’s important to check for any leaks. Open the ball valves and run water through the heater to verify that there are no leaks from the newly installed elements.

Step 10 Reattach the wires to their respective elements. Connect the wires back to the terminals of each element, ensuring a secure connection.

Step 11: Restore the power supply to the water heater. 

Finally, locate the on/off power switch for the water heater and turn it on.

Reason 6: Malfunctioning Thermostat

If the thermostat of your Stiebel Eltron water heater is faulty, it can cause the water to get overheated. As a result, the safety upper limit button will keep tripping. 

If the thermostat of your water heater is faulty, you will notice some other symptoms as well. For example: 

  • The water temperature fluctuates automatically. Either it gets overheated or underheated. 
  • Strange noise coming from the water heater.
  • The thermostat might not get power

Sometimes, the reset button on the thermostat itself can malfunction. As a result, it keeps tripping, even though the water isn’t hot beyond the safety limit. 

How to Fix it:

You have to replace the faulty thermostat. If the reset button is faulty, replacing the thermostat will take off this as well. 

As replacing the thermostat is a complicated process, you should consult a professional dealer. If you want to do it by yourself, the following video might help.

Reason 7: Faulty Control Board 

If none of the above reasons are true for the water heater repeatedly tripping problem, you might have a faulty control board. 

The main element that can be damaged in the control board is two large “blue” capacitors on the board that power the entire system. These capacitors are connected in a specific way, forming a star or triangle configuration. It creates lower voltage points between certain connections.

The capacitors lose their capacity over time causing the control board to fail. Also, if the wiring connection from the main board is corroded or damaged, the control board can malfunction. 

When the control board of the electric water heater malfunctions, it can not properly detect the point when the system should stop heating the water. As a result, the water will overheat causing the heater to trip. 

How to Fix it:

First, Carefully examine the capacitors of the control board for any signs of physical damage, such as bulging, leakage, or discoloration. If you notice any abnormalities, they are likely defective. Don’t forget to check the wiring connection.

If the capacitors are damaged, replacing them should fix the issue. For replacement see the model number of the capacitor from its body. If the wiring connection is loose, tighten the. Corroded wires need to be replaced. 

loose wiring connection of control board of stiebel eltron water heater

If replacing the capacitors and wirings doesn’t work, there are problems with the main control board. And for sensitive components like the control board, it is recommended to have it checked and fixed by a professional.

How Do I Reset My Stiebel Eltron Tankless Water Heater?

When the Stiebel Eltron trips, you have to reset the high-limit button to make the heater operate again. Here’s how to reset the Stiebel Eltron water heater after tripping. 

Step 1: Before performing the reset, ensure your safety by turning off and locking out all circuit breakers connected to the water heater.

Step 2: Using a screwdriver, remove the screw that secures the cover on the right side of the unit. Open the cover to access the internals of the water heater.

Step 3: Now, look for the thermal safety resets located on the top of each copper heating vessel. 

wiring connection from the flow sensor of stiebel eltron water heater

Step 4: To reset the thermal safety, use a non-conductive device such as a pencil with an eraser. Press the reset button or switch on top of each copper heating vessel.

Step 5: When pressing the reset button, listen for a click. If you hear a click when the button is depressed, it means the thermal safety has been reset successfully.

Step 6: Close the cover of the water heater and securely reinstall the screw. 

Step 7: Finally, restore the power supply to the water heater. Your Stiebel Eltron water heater has now been reset.

If you want to learn more about the resetting process of other Stiebel Eltron models, check the linked article.


Why is my Stiebel Eltron hot water not hot?

Your Stiebel Eltron water heater is not hot due to excessive flow rate adjustment, a faulty heating element, or a malfunctioning thermostat. A clogged heat exchanger or insufficient power supply can also cause this issue. 

What is the eco mode on the Stiebel Eltron?

The ECO mode on the Stiebel Eltron water heater is a setting that saves energy and prevents the growth of bacteria in the water tank. In ECO mode, the temperature of the water tank is reduced by 15 °C. 

Why is my electric water heater not staying hot long?

Your electric water heater is not staying hot long enough due to the accumulation of sediment, a malfunctioning heating element, a broken dip tube, and a lack of insulation. These factors contribute to a decreased supply of hot water. 

Final Words

That’s all about the Stiebel Eltron water heater keeps tripping. Hopefully, after reading this article, you should be able to identify the problem and resolve it. 

Remember to always prioritize your safety while working on the water heater. And consider seeking professional assistance when necessary.

In addition to this problem, you can pay a visit to this linked article on adjusting the Stiebel Eltron water heater temperature if you ever face such issues.

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