A.O. Smith 300 Series Instruction Manual page 42

OPERATING STATES
The current operational state of the water heater is displayed on the Desktop screen as the "Status." The common operational
states are described in the table below.
State
Standby The water heater is not in an active heating cycle. IE: the Tank Temperature is at or above the Operating Set Point.
Input Verification The control system is conducting a diagnostic check at the beginning of a heating cycle.
A Fault condition is detected by the control, the Enable/Disable switch on front panel is in disable position, or the Building Man-
Water Heating
Disabled agement system Enable/Disable is an open circuit.
Pre-Purge The Combustion Blower is energized to flush residual flue gases from the combustion chamber prior to ignition.
The Spark Igniter is energized.
Spark Igniter En-
ergized
Ignition Activation The 24-volt gas valve is energized and opens to allow fuel gas to flow to the Main Burner.
Ignition Verification The control system is monitoring the flame sensor for the required minimum flame sensing current.
Ensure the water heater is properly grounded. Flame sensing requires an adequate earth ground. If the water heater is not
properly grounded it will cause ignition failure.
Inter-Purge The Combustion Blower is energized to flush residual fuel gas from the combustion chamber after a failed ignition attempt.
Ignition was successful, flame sensing current has been established. The water in the storage tank is being heated.
Heating
Post-Purge The Combustion Blower is energized to flush residual flue gases from the combustion chamber at the end of a heating cycle.
Fault The control system has detected a Fault condition. Heating operation is disabled until the Fault condition is corrected. Power to
the water heater must be cycled off and on at the breaker to reset the control system.
Note: Cycling power will not reset the control system if the condition that caused the Fault has not been corrected.
CONTROL SYSTEM MENUS
From the Desktop screen pressing "Menu" on the LCD Touch Display will display the "Main Menu" this is where all control system
menus are located. The table below describes the control system menus.
Menu
Most commonly accessed menu. Contains the Operating Set Point and Differential user settings.
Temperatures
This menu displays the current state of all pressure switches and the ECO (open/closed). The on/off status of the Com-
Heater Status
bustion Blower, gas valve, Spark Igniter, flame sensor and other monitored water heater components are displayed in this
menu.
Display Settings Temperature units (°F or °C), the LCD appearance (brightness/contrast) and backlight delay user adjustable settings are
located in this menu.
Elapsed time of operation, total heating cycle time, heating cycle count, heating on time along with UIM and CCB software
Heater Information
revisions can be viewed in this menu.
Current Fault Displays any current Alert or Fault messages.
Fault History This control system menu retains a list of the last nine (9) Fault and Alert messages with a time stamp. The newest event
will replace the oldest. Faults will clear after 30 days.
Fault Occurrence This control system menu retains a running total of how many times each Fault condition has occurred since the water
heater was first installed. The data does not clear and cannot be reset.
Restore Factory Defaults This control system feature allows the user to restore control system user settings to their factory default settings. Display
Settings preferences ARE NOT changed when factory defaults are restored.
Help Screens Text based operational and user information explaining how to change user settings, navigate the control system menus
and icon descriptions.
Table 12. Operating States
Description
Table 13. Control System Menus
Description
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