How do I properly flush a Rinnai tankless water heater?

To properly flush a Rinnai tankless water heater, you will need to turn off the power and water supply to the unit. Connect a pump and hoses to circulate a descaling solution through the system for about 45 minutes. Then, flush the unit with clean water to remove any remaining solution. Finally, reconnect the power and water supply and test the unit to ensure it is working properly.