Diagnostic Codes - Rinnai RUCS65i series Installation And Operation Manual

Diagnostic Codes

This water heater is designed to display diagnostic codes. If there is a potential operation concern refer to the
code and remedy on the next page.
Diagnostic Information (on status monitor)
- - Initial (When unit is connected to power).
(non-displayed) Standby (power is supplied but there is no demand for hot water).
1,2,3 or 4 Hot water is being supplied without controller.
ON Hot water is being supplied with controller
FL or FH Stands for Forced Low and Forced High combustion. Only seen during the gas pressure
setting procedure which is done when certain components are replaced.
Error code flashing The error code will stop flashing after the problem is corrected and the water heater
supplies hot water.
To Display Diagnostic Information (with controller)
To display the most recent diagnostic information code press and hold the "On/Off" button for 2 seconds on the
MC-91-2 controller. While holding the "On/Off" button press the up button. The last 9 diagnostic codes will
flash one after the other. To exit this mode press the "On/Off" and up button as before.
To enter or exit the maintenance monitor information mode, press and hold the down button for 2 seconds and
without releasing it press the ON/OFF button.
To obtain the water flow rate: press the up or down buttons until "01" displays. The water flow rate will then
appear. For example "58" means 5.8 gal/min.
To obtain the outgoing water temperature press the up or down buttons until "02" displays. The temperature
will appear in degrees Fahrenheit.
No.
56
Data
01 Water flow rate
02 Outgoing water temperature
Status Monitor
Unit
0.1 gal/min
Degrees Fahrenheit
KCM Series Manual
Status Monitor