Bosch Tankless Water Heater Reset Button [Gas & Electric]

This Bosch tankless water heater reset button guide will explain how to do it for both gas and electric models so that you can get hot water again. 

To reset the electric unit, you can locate the reset buttons on the thermal cutouts situated atop each heating element. While most gas-powered tankless units may have a dedicated reset button, some models may require you to reset the unit by using the power button. 

No matter the case, our step-by-step instructions will help you navigate the reset process for both gas and electric units. Eventually, that will bring back the comfort of a constant flow of hot water.

How To Reset Bosch Tankless Water Heater [Gas Units]

For gas-powered Bosch tankless water heaters, some models have a dedicated reset button that you can use to reset the unit. It is typically found on the front of the heater, and the button is named “RESET”. Press the reset button until you see the unit initiate the reset process. This will clear any error codes or malfunctions and restore the water heater to its default settings.

However, in certain gas-powered Bosch tankless water heater models, the reset process may involve using the power button instead of a dedicated reset button. Here are the steps to reset your unit using the power button:

  • Locate the power button on your Bosch gas tankless water heater. It is typically located on the control panel or front of the unit.
  • Press and hold the power button for more than 3 seconds.
  • Keep holding the power button until the appliance initiates the start-up sequence.
  • Release the power button once the start-up sequence is complete. At this point, the gas tankless water heater should be reset and ready to provide you with hot water.
bosch tankless water heater reset button

Bosch Tankless Water Heater Reset Button [Electric Units]

The process of resetting a Bosch tankless water heater may vary depending on the specific model you have. To reset your Bosch electric tankless water heater, just follow the below simple steps:

  • Step 1: Turn off the power supply to the water heater. This can be done by turning off the circuit breaker that controls the water heater.
  • Step 2: Remove the front panel of the heater. You can then identify the thermal cutouts positioned atop the heating elements.
  • Step 3: Press the red button that is placed on the center of the cutouts. The thermal cutouts will be reset after pressing the red button. Also, the heater will also be reset.
  • Step 4: You should put the front cover back onto the water heater and turn the power back on by switching on all the circuit breakers that are connected to the unit.

How Can You Determine If The Thermal Cutout Is Defective Or Not?

It is really important to check every thermal cutout of your water heater before resetting. Because a faulty thermal cutout won’t let you reset the unit. Therefore, make sure you have checked every cutout.

Below I have noted some simple steps that you can follow so that you can check thermal cutouts very easily:

  1. Turn off the power to the heater. This is crucial to ensure your safety while working on the unit.
  2. Remove the cover of the heater. This may involve unscrewing or unlatching the cover, depending on the specific model. Locate the thermal cutouts on the top of each heating module. These are safety devices designed to protect the heater from overheating.
  3. Check for continuity through each cutout. Using a multimeter set to the resistance or continuity mode, place the probes on either side of the cutout and measure the resistance. A continuity value of fewer than 0.5 Ohms indicates that the cutout is functioning correctly. However, a continuity value greater than 0.5 Ohms suggests that the cutout has tripped or is faulty.
  4. If any cutout has tripped or shows a faulty reading, it is essential to determine and resolve the cause. Tripping usually occurs under exceptional circumstances, such as excessive heat buildup. So, it’s important to investigate and address the underlying issue.
  5. Additionally, verify that the heater’s inlet filter screen and all outlets served by the heater are clear of debris. Any obstructions can impede the flow of water and affect the heater’s performance like
  6. Additionally, verify that the heater’s inlet filter screen and all outlets served by the heater are clear of debris. Any obstructions can impede the flow of water and affect the heater’s performance like you won’t get enough hot water from your water heater.
  7. Lastly, ensure that the heater is only being fed with cold water. Preheated water can strain the unit and potentially lead to malfunctions.

By following these steps, you can effectively check the thermal cutouts, inspect whether they are defective or not, and continue with your reset process.

When Do You Need To Reset Your Bosch Tankless Water Heater?

When encountering an error code on your water heater, it’s generally a good idea to try resetting the unit as the first troubleshooting step. It’s important to note that while resetting the heater often resolves minor issues, it may not always clear the error code.

In some cases, there might be underlying problems that require additional troubleshooting or repair. The following are common error code situations that may require a reset:

  1. Error Code C1 Or C2: To resolve the issue of excessive blockage during startup, the Bosch Tankless Water Heater will need to be reset. This will clear the error code C1 or C2 which is flashed when the unit detects an excessive blockage during startup.
  1. Error Code E3: When the Bosch tankless water heater detects flue gas temperatures above 167 °F (75 °C) or sustained temperatures above 145 °F (63 °C) for two minutes, it will show error code E3 and shut off the burner for safety reasons. To resolve this issue, descale the unit.
  1. Error Code E4: An error code E4 will appear if the air temperature inside the cabinet reaches or stays above 176 °F (80 °C) for two minutes. That will cause the appliance burner to cut off as a safety measure against overheating. To troubleshoot the E4 error code, check inside the cabinet for any concentric vents or flue gas leaks. 
  1. Error Codes F2, F3, F7, & F8: An internal error in the electronic control unit can trigger error codes F2, F3, F7, and F8 on a Bosch Tankless Water Heater. To resolve these error codes, it is recommended to contact a professional technician for diagnosis and repair.

Here you can explore our dedicated guide on Bosch tankless water heater error codes for detailed information.

What Makes The Reset Button Trip On the Tankless Water Heater?

There are several reasons why the reset button will trip in your Bosch tankless water heater. I’ve outlined all the possible reasons below:

01. High Temperature Of Water

The reset button on a hot water heater also known as thermal cutoff, is designed to trip and shut off power to the heating elements when the water temperature becomes too hot. 

When the temperature of the water in the hot water heater reaches or exceeds the safety limit (typically around 180 degrees Fahrenheit), the reset button will trip and cut off power to the heating element or gas burner. The Thermal cutoff is a safety mechanism that prevents the water heater from overheating and potentially causing damage or creating a safety hazard.

02. Clogging In Water Paths

If your hot water heater continues to trip the reset button, it is important to address the underlying cause of the overheating. In many cases, the issue may be due to obstructions in the plumbing system that restrict water flow and cause the water to heat up too quickly.

Showerheads, faucet aerators, and the water heater’s filter screen are typical sources of blockages in the water flow. Over time, these components can become clogged with sediment or mineral buildup, which reduces water flow and can cause the water heater to overheat.

It is important to regularly inspect and clean these components to ensure proper water flow and prevent the overheating of the water heater.

03. Blockage In Inlet Filter Screen

In addition to checking the plumbing system, there are a few other things you can do to address issues with the reset button on your Bosch Electric Tankless Water Heater.

First, it is important to inspect the inlet filter screen for blockage and clean it if necessary. This filter helps to prevent sediment and debris from entering the water heater, which can cause blockages and lead to overheating.

04. Preheated Water

Another potential cause of the reset button tripping is if the water feeding the unit is preheated. Bosch Electric Tankless Water Heaters are designed to work with cold water only. So, feeding it with preheated water can cause the unit to overheat and trip the reset button. Make sure that the water feeding the unit is at a suitable temperature and is not preheated.

05. Malfunction Of Heating Elements

If you have checked the plumbing system and ensured that the water feeding the unit is at a suitable temperature but the thermal cutouts continue to trip, it may be necessary to inspect the heating elements for electric continuity. 

Over time, heating elements can become damaged or worn out, which can cause them to malfunction and trip the thermal cutouts. Inspecting and replacing the heating elements if necessary can help to address this issue.

What Is The Purpose Of Reset Button On Bosch Tankless Water Heater?

The reset button on a Bosch tankless water heater is typically used to reset the heater’s internal circuitry when it has detected a problem or fault. In the event of a fault or malfunction, the reset button can be used to restart the heater and clear the fault code. 

Also, the reset button is a safety feature on a water heater that shuts off the heating element or burner when the water temperature exceeds the preset limit. Also, it interrupts power in the event of a malfunction, such as a power surge or a faulty thermostat. 

However, it is important to note that simply resetting the heater may not fix the underlying issue that caused the fault in the first place. If you are experiencing issues with your Bosch tankless water heater, it is recommended to check our complete guide on Bosch tankless water heater troubleshooting.


How do I know if my tankless water heater needs to be reset?

Signs that your water heater needs to be reset include a lack of hot water or water that is not as hot as usual, longer heating times, or a tripped reset button. Resetting the unit may help troubleshoot the issue. Nevertheless, a professional plumber should handle any persistent issues.

What do you need to be careful of during the resetting process?

Before using the reset button, make sure to follow the manufacturer’s instructions and safety guidelines. Ensure that the unit is turned off and disconnected from the power source before attempting to reset.

What should I do if the reset button on my water heater doesn’t work?

If the reset button on your Bosch tankless water heater doesn’t work, ensure it is not jammed or damaged. Check the power supply and circuit breaker. If the issue persists, contact a qualified service technician for assistance or Bosch technical support.

Can I reset my water heater multiple times if the issue persists?

Resetting your Bosch tankless water heater multiple times is not recommended if the issue persists. While resetting can help resolve minor glitches, persistent issues may require professional diagnosis and repair. 


Resetting a Bosch tankless water heater is a straightforward process that requires basic knowledge of electrical appliances. Simply press the red buttons on the thermal cutouts of the heating elements and the water heater will be reset.

This guide aims to offer clear solutions to any confusion or problems regarding the Bosch tankless water heater reset button. 

Well, maintenance is necessary for your water heater if you want your reset button to not trip. Therefore, I recommend you check out our ultimate Bosch tankless water heater maintenance guide. We’ll be happy to see you there.

Best of luck!

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