Rheem On Demand Water Heater Troubleshooting – Quick Fixes for a Faulty Rheem Tankless Water Heater

Rheem has built a reputation for offering some of the most reliable and effective water heaters on the market. Their tankless water heaters are as user-friendly and durable as possible, so it is no surprise that many homeowners rely on them for their hot water needs. Despite their outstanding reputation, sometimes users will encounter some technical difficulties.

Rheem On Demand Water Heater

If you are dealing with error codes or other electronic issues with your tankless Rheem water heater, we are here to help.

While water heaters can underperform for many reasons, including a lack of power, faulty thermostats, corrosion issues, and improper installation, Rheem tankless water heaters feature complicated internal electronics, so the problem is usually displayed with an error code. If you are dealing with an electrical issue, you can usually solve the problem by resetting your water heater.

Related: Rheem Water Heater – Ultimate Troubleshooting Guide

How Do I Reset My Rheem Tankless Water Heater?

There are multiple reasons why you might need to reset your Rheem water heater. Overloading is a common issue that you can usually correct with a reset. Resetting your water heater will bring its settings back to the default factory settings, which is usually enough to get it working correctly.

While there are various models, most Rheem tankless water heaters have a simple reset button. To reset the heater, start by turning the water heater’s gas valve to the OFF position. After waiting several seconds, you can turn the valve back to the ON position and press the reset button.

Raheem Tankless Water Heater

Where is the Reset Button on a Rheem Hot Water Heater?

The actual reset button is located just above the unit’s thermostat, and it will be labeled ‘Reset Button’ and be bright red.

Rheem Water Heater Troubleshooting – Addressing Error Codes

We will now walk you through some of the most common error codes and explain how you can address them:

Error No Code

This code usually signifies a water flow issue. The display screen will not show an error code, but it will display the temperature, even if the water heater is not working.

Fixing the Issue

To fix flow issues that do not show an error code, you will need to adjust the water flow into the water heater. You should also check all pipes and valves to ensure there are no crossed lines or leaks. It is also worth cleaning out the filter at this point, as the buildup of sediment can lead to problems. Make sure everything is reconnected properly and see if that addressed the problem.

Error Code P1

P1 a common error code that often indicates a reduced water flow. You may notice that the water heater is still working, but they can also but at reduced pressure.

Fixing the Issue

You will need to check the water pressure from the aerator. In most cases, cleaning it out will help and can even eliminate the code. Once you have removed any sediment and debris from the intake filter, try adjusting the temperature and flow rate. If this does not work, visually inspect the flow sensor and contact the Rheem customer service line if you notice a sensor issue.

Error Code 1L

This code indicates that you need to service or clean your water heater. In most cases, this is due to excess limescale buildup, so a thorough descaling could be enough to clear the code.

Fixing the Issue

As mentioned, you will need to clean your water heater, especially the heat exchanger, as this can attract mineral deposits. Make sure you read through your owner’s manual and follow the proper cleaning routine. You may also want to lower the altitude settings, as this will help prevent the future buildup of limescale.

Error Code 05

This code is triggered for two reasons. Either there is a blockage somewhere in the water lines, or the pipes have not been properly connected. Addressing the issue will remove the error code.

Fixing the Issue

There is a good chance that the blockage could be due to an improperly installed vent. You should check the fittings and make sure they are secure. You should also inspect the vent and make sure it is clear of dust and debris by using compressed air. Fit everything back according to the manual. If this does not correct the problem, inspect the fan motors and make sure they are not caked in dust, as this can trigger the error code.

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Why Does My Tankless Water Heater Keep Shutting Off?

If your water heater is shutting off, rather than just producing error codes, it could be possible that your hot water requirements are exceeding what the unit is capable of producing. If you are working the water heater too hard, it will shut down, as this helps protect the electronics.

If you cannot afford a more powerful water heater and you do not have room to install a water heater with a built-in water tank, you can try reducing the amount of hot water you use. Try taking shorter showers and install a more energy-efficient shower head. You can also try washing your clothes with cold water. You should also spread your hot water usage out, meaning taking showers and running the dishwasher with plenty of time between the two.

If you are using an electric tankless water heater, you can also switch to a gas-powered option, as these tend to be more capable when it comes to dealing with significant hot water requirements.

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Final Words

Rheem water heaters feature programmable display screens. Not only do these screens make it easy to adjust the settings of your water heater, but they can also indicate performance issues with error codes. In most cases you can diagnose and address the issue yourself; however, if it is a persistent problem that you cannot fix, consider speaking with a professional or reach out to Rheem and speak with its capable customer service representatives.

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