What does the priority light mean on a Rheem tankless water heater?
What does the priority light mean on a Rheem tankless water heater? Category: home and garden home appliances. 3.9/5 (7,932 Views . Press the “Priority button” on the temperature controller. The green Priority light will glow indicating that this controller is controlling the temperature and that the Rinnai Tankless Water Heater is ready to supply hot water. What does the Rheem error code 21 mean? Rheem error code 21 means the air intake filter is not working correctly. Rheem error code is found on indoor units only and can be caused by a dirty air filter door or improperly installed...