rheem tankless water heater troubleshooting

Troubleshooting Common Issues with Rheem Tankless Water Heaters

Rheem tankless water heater troubleshooting is essential to maintaining these units’ performance and functionality. While these Rheem water heaters are generally reliable, occasional issues that require troubleshooting and repair may arise. This piece will explore common troubleshooting steps for Rheem tankless water heaters, including problems with water temperature, ignition failure, and error codes. 

By understanding these troubleshooting techniques, homeowners can quickly identify and resolve issues with their tankless water heaters, especially Rheem products, ensuring a consistent hot water supply and optimal performance.

Rheem Tankless Water Heater Troubleshooting

Rheem tankless water heaters provide an efficient and reliable hot water supply. However, like any complex appliance, they can occasionally encounter problems. This section will guide you through troubleshooting common Rheem water heater (tankless) issues. These steps can resolve the problem and restore your unit’s optimal performance.

No Hot Water

If you’re experiencing a lack of hot water from your Rheem tankless water heater, follow these troubleshooting steps:

    • Check the power supply:

Ensure the unit receives power and the circuit breaker or fuse is not tripped. Consult the Rheem tankless water heater troubleshooting manual for specific instructions.

    • Inspect the water flow:

Verify that the water flow is adequate by checking the faucet or showerhead for any obstructions or clogs.

    • Clean the water filter:

Sediment buildup in the water filter can restrict flow. Clean or replace the filter as recommended in the user manual.

Insufficient Hot Water:

If you’re getting lukewarm or cold water instead of hot water, consider these troubleshooting steps:

    • Check the temperature setting: 

Ensure the temperature is set appropriately on the unit. Refer to the Rheem tankless water heater troubleshooting manual for the recommended temperature range.

    • Verify water flow and pressure:

Insufficient or low pressure can affect the heater’s performance. Confirm that the water supply valves are fully open and the pressure is within the required range.

    • Descale the heat exchanger:

Over time, mineral deposits can accumulate on the heat exchanger, reducing its efficiency. Consult the Rheem tankless water heater troubleshooting manual for instructions on descaling the unit.

Error Codes Displayed:

If your Rheem tankless water heater displays error codes, follow these steps:

    • Refer to the Rheem tankless water heater troubleshooting manual:

Each error code corresponds to a specific issue. Consult the manual to identify the error code and follow the recommended troubleshooting steps.

    • Reset the unit:

In some cases, resetting the unit can resolve minor issues. Locate the Rheem tankless water heater reset button (refer to the user manual for its location) and press it to reset the system.

Flame Failure or Ignition Problems:

If your Rheem tankless water heater fails to ignite or experiences flame failure, follow these troubleshooting steps:

    • Check the gas supply:

Ensure that the gas supply to the unit is turned on and the gas valve is open. If using propane, ensure the tank is not empty.

    • Verify the gas line:

Inspect the gas line for any leaks or blockages. If you suspect a gas leak, turn off the gas supply immediately and contact a professional.

    • Clean the burner:

Accumulated debris or dust on the burner can disrupt ignition. Clean the burner using compressed air or a soft brush per the Rheem tankless water heater troubleshooting manual.

    • Check the spark electrode:

Ensure the spark electrode is clean and properly positioned. Gently clean any residue or buildup on the electrode.

    • Water Temperature Fluctuations:

If you’re experiencing inconsistent water temperatures from your Rheem tankless water heater, try these troubleshooting steps:

    • Check for crossed hot and cold water lines:

Ensure the hot and cold water lines are properly connected and not reversed.

    • Inspect the temperature sensor:

The temperature sensor monitors the water temperature. Verify that it is clean and correctly positioned.

    • Adjust the temperature rise:

The temperature rise is the difference between the incoming water temperature and the desired output. Consult the Rheem tankless water heater troubleshooting manual to determine the recommended temperature rise and adjust it accordingly.

Tripping of Safety Features:

If your Rheem tankless water heater repeatedly trips safety features like the high limit switch, follow these steps:

    • Check for blockages in the venting system:

Obstructions in the vent pipes can cause overheating and trigger safety shutdowns. Ensure the venting system is clear and free of debris.

    • Inspect the heat exchanger:

A dirty or malfunctioning heat exchanger can lead to overheating. Clean or repair the heat exchanger as instructed in the Rheem tankless water heater troubleshooting manual.

    • Verify proper airflow:

Ensure the unit has adequate space for proper airflow and is not obstructed by objects or debris.

How to Turn on Rheem Tankless Water Heater

Follow these simple steps to switch on a Rheem tankless water heater:

    • Locate the power switch:

The power switch may be situated on the device itself or a nearby wall-mounted control panel, depending on the model.

    • Turn on the gas supply (for gas models):

If you have a gas-powered Rheem tankless water heater, turn on the gas supply valve. If you’re going to use propane, be sure the tank isn’t empty.

    • Examine the water supply valves:

Ensure the hot and cold valves attached to the unit are fully open. These valves are usually found in the plumbing lines that go to the tankless water heater.

    • Turn on the power switch:

If it is off, toggle it on.

If you are looking to secure a Rheem water heater with little or no technicalities in operation, a Rheem RTEX-24 24kW 240V Electric Tankless Water Heater is what you need. They are quite easy to turn on, evidently in their self-modulating power control.

Final Verdict

Rheem tankless water heaters offer efficient hot water solutions, but occasional troubleshooting may be required. Following the tankless water heater troubleshooting manual and the steps outlined in this article can address common issues and ensure optimal performance. Remember, if you encounter complex problems or are unsure about any step, it’s always advisable to consult a professional technician for assistance. Remember that, for better efficiency, it is always advised to use the best recirculation pumps for tankless water heaters.


How Do I Install a Recirculation Pump on a Tankless Water Heater?

To install a recirculation pump on a tankless water heater, follow these steps: 

    • Shut off the power and water supply to the unit.

    • Install the recirculation pump on the hot water outlet of the tankless water heater.

    • Connect the pump to a dedicated return line or integrate it with the existing plumbing system.

    • Restore the power and water supply.

    • Test the recirculation pump to ensure proper functionality.

What Is the Best Rheem Tankless Water Heater for a Large Home?

The Rheem RTGH-95DVLN tankless water heater is regarded as one of the top Rheem tankless water heaters for large households. It has a high flow rate of up to 9.5 gallons per minute (GPM) and can simultaneously give hot water to many showers. Thanks to its condensing technology, energy economy, and innovative features, it offers enough hot water for a big household.

How do I keep my tankless water heater performing at its best?

Follow these tips to get the most out of your tankless water heater. Clean or descale the device regularly to eliminate mineral accumulation according to the manufacturer’s instructions. If required, inspect and replace the water filter. Maintain the heater’s water pressure and flow. Check for gas leaks (if any) and make sure the gas supply is steady. Maintain proper ventilation and keep the surrounding area clear of debris. Finally, arrange regular expert maintenance to identify and fix potential concerns immediately, ensuring your tankless water heater runs effectively and dependably.

How do tankless water heaters reduce energy bills?

Tankless water heaters save energy by removing the standby heat loss typical tank water heaters face. They simply heat water as needed, eliminating the continual energy usage of maintaining a big hot water tank. This on-demand heating approach saves energy waste and utility expenses, potentially saving money on energy bills.

What is the average lifespan of a tankless water heater?

A tankless water heater has an average lifespan of roughly 20 years. The actual longevity, however, might vary based on factors such as consumption habits, water quality, maintenance methods, and the precise type and brand of the water heater.