Description of operation, Operating instructions, Features available on temperature controllers – Rinnai RC98HPE User Manual
Page 5

Manual - Rinnai Condensing Water Heaters
5
The Rinnai water heater is one of the most advanced 
water heaters available. It provides a continuous 
supply of hot water at a preset temperature. 
This appliance is a condensing tankless, direct vent 
appliance where air is brought in from the outside and 
combustion gases are exhausted to the outside. This 
appliance uses a concentric vent where the outer 
passage way brings in air from the outside, and the 
inner passage way expels the combustion gases. 
While electricity, water, and gas supplies are 
connected, the Rinnai water heater produces hot water 
whenever a hot water tap is open. 
Ignition is electronic. There is no pilot light consuming 
gas while the water heater is not being used. The gas 
burner lights automatically when the hot water tap is 
opened and goes out when the tap is closed. 
Installation of the temperature controller is highly 
recommended. The temperature controller can set the 
temperature within a specific range and can provide 
error codes to diagnose any problems. 
The temperature of the outgoing hot water is constantly 
monitored. The Rinnai water heater may adjust the 
water flow in order to maintain the temperature setting. 
The water flow may vary from summer to winter due to 
the difference in ground water temperature. 
Description of Operation
Features Available on Temperature Controllers
The MC-91 temperature controller is supplied with the appliance. Additional functions are available through the 
use of optional controllers. 
Operating Instructions
Features
MC-91
MC-100
BC
-10
0 
MC-502
Description
Call
Sends a short series of beeps to all controllers in the system. It is 
not an intercom. 
Clock
12 hour AM/PM clock.
Function
Used on this model to set the clock or sound volume.
In Use Indicator
Indicates that hot water is being supplied (i.e. a hot water tap is 
open). 
ON/OFF Button
Used to turn the water heater ON or OFF.
Power Save
Allows the temperature controller to be in an energy saving 
mode. 
Priority Button / 
Indicator 
Indicates that this controller is setting the temperature . Priority 
can be switched to another controller by pressing its Priority 
Button when no hot water is running. 
Sound Volume
Used to adjust the voice prompt volume.
Temperature Display
Shows the temperature setting.
Thermostat
Increases or decreases the temperature setting.
Water Smart / Bath Fill 
Button / Indicator 
Used to select the Water Smart / Bath Fill Function to fill a bath 
with a predetermined volume of water. 
Water Volume
Used to select the water volume for the Water Smart / Bath Fill 
Function. 
MCC-91
Error Codes
When a fault is detected an error code flashes at the temperature 
display on models MC-91, MCC-91, and MC-502; and flashes at 
the clock display on models MC-100 and BC-100. 
