For reliable operation Rinnai continuous flow water heaters in residential applications should be serviced every two years. For reliable operation the Rinnai iHeat should be serviced annually. For reliable operation the Rinnai Energysavers should be checked by a licensed tradesperson every two years, including inspection of the flue system. For reliable operation Rinnai Portable Convectors should be checked by a licensed tradesperson every two years. For reliable operation Rinnai Super Ray heaters should be checked by a licensed tradesperson every two years. For commercial applications Rinnai has a recommended commercial maintenance and servicing schedule. This is available on request.