Emerson AC4 User Manual

The Override Output feature allows you to manually change the state of any digital output to ON or 

OFF, overriding automatic control by the Liebert AC4

 

(the default setting for all outputs). This menu 

also allows you to release the manual override, returning any output to automatic control.
There are two ways to override automatic control of outputs:

• Use the Override Output menu, as described in this section, to turn any output ON or OFF.
• Use the hardware switch on the circuit board to force all four outputs ON at the same time

(see Item F - Manual Override Switch (outputs) in 1.6 Controller Board Overview).

After an output is forced manually ON or OFF, it remains in that state until returned to automatic 

control through this menu.
Table 20 summarizes the four types of control, including the abbreviated message that appears on 

the LCD and in log reports.

 

To force an output point ON or OFF or return it to automatic control:

• From the Main Menu, use the arrows

↑↓

 to

 

choose System and 

Control, then press Enter ↵ (see 7.1 Login for help).

• Enter your password at the Login screen.
• From the System and Control Menu, use the arrows

↑↓

 to

 

choose 

Override Output, then press Enter ↵.

Select an Output
The Select Output menu, shown at right, displays the current status 

of all four outputs.

• Use the arrows

↑↓

 to

 

choose the output you want—for example, 

Device_1—and press Enter ↵.

• From the Override Output menu, use the arrows

↑↓

 to

 

choose one 

of these options:

• AUTO - return to automatic control
• FORCE ON - manually turn this output ON (operating)
• FORCE OFF - manually turn this output OFF

• Press Enter ↵.

AUTO

Automatic

Controlled by Liebert AC4 

(default for all outputs)

FORCE ON

Manually ON

This output has been forced ON 

(operating) or OFF via the Override 

Output menu

FORCE OFF

Manually OFF

HW FORCE ON

Manually ON 

(all outputs)

All outputs have been forced ON 

(operating) via the hardware switch on 

the circuit board (see Item F - Manual 

Override Switch (outputs) in 

VIEW STATUS

↑↓=NEXT

↵

=SELECT

LOGIN

AAAA

↑↓=SELECT

↵

=NEXT/END

SETUP SYSTEM

CLEAR ALARMS & LOGS

↑↓=NEXT

↵

=SELECT

OVERRIDE OUTPUT

DEVICE_2

 AUTO

↑↓=NEXT

↵

=SELECT

DEVICE_3

 AUTO

DEVICE_4

 FORCE ON

SELECT DEVICE_1

FORCE ON

↑↓=SELECT 

↵

=END