The Rinnai Bathroom Deluxe Controller  works in conjunction with the Rinnai Kitchen Deluxe Controller.
Digital controllers allow you to select the exact temperature of the hot water at the tap within the controller temperature range. This has a number of benefits:
Safety: If you have young children, the hot water can be pre-set to a child-safe level for the period while you are filling the bath—a safety interlock feature prevents the water temperature from being adjusted from another controller while the bathroom controller is operating and hot water is flowing.
Ability to transfer control back to the kitchen controller at the press of a button.
No need to mix hot and cold water, this reduces the effect of temperature spiking when another tap in the building is turned on
You use your Rinnai INFINITY continuous flow gas hot water unit more efficiently as less gas is required to heat water to 40 °C (typical shower temperature) than at 55 °C (default temperature without controllers)
Allows diagnosis of problems (such as gas supply disruption) when the appliance is serviced by displaying 'error' codes, which the service person can utilise.