How to Troubleshoot Rheem Tankless Water Heater Codes

Meredith Jameson

Rheem tankless water heaters use a condensing technology to offer continuous hot water without the use of a large water tank. The water is heated on demand only, which reduces energy consumption as well as overall energy costs.

Rheem tankless water heaters include a digital temperature control and display panel that will show an error code when a problem has occurred with the unit. Troubleshooting the error codes on the display panel may assist users attempting to resolve the issue themselves without the need for a service technician.

  1. Turn off the hot water faucet when an error code is displayed. Use the included remote control to turn off the main power switch. Wait five minutes and turn the power back on. Turn the hot water faucet back on.

  2. Check the gas valve and open it completely if the error code is “11” and contact your gas company if the error code is “12,” indicating that the gas supply was interrupted.

  3. Open the hot water faucet fully if the error code is “15,” indicating a low hot water supply.

  4. Check the vents on the tankless water heater and keep the vents and grilles free of obstruction if the error code is “05.” Wipe the vents and grilles with a damp cloth to remove dirt or debris.

  5. Contact Rheem for additional service if the error code is “13,” “1L” or the previous error code does not clear even after corrective actions.