Emerson Static Transfer Switch LED and Push Button Description, LED and push button description

Operating the Liebert STS2 LED Display

14.1.2LED and Push Button Description

The following table defines the LEDs and push buttons in the LED display:

Table 15 LED and push button description

Symbol	LED	Description	Action
			A green LED is lit if the Source 1 input power is present. This LED
A	Green	Source 1 power is present	only indicates that power is present to the power supply; it does not
			indicate if the power is within the programmed tolerances of the unit.
			A green LED is lit if the Source 2 input power is present. This LED
B	Green	Source 2 power is present	only indicates that power is present to the power supply; it does not
			indicate if the power is within the programmed tolerances of the unit.
C	Green	Source 1 within tolerance	A green LED is lit if Source 1 power is within the programmed
			tolerance for all phases.
D	Green	Source 2 within tolerance	A green LED is lit if Source 2 power is within the programmed
			tolerance for all phases.
E	Green	Source 1 SCRs on	A green LED is lit when the SCRs for Source 1 are closed.
F	Green	Source 2 SCRs on	A green LED is lit when the SCRs for Source 2 are closed.
			A yellow (amber) LED is lit when source transfers are inhibited
G	Yellow	Source transfer inhibited	(locked out) by a hardware condition. Connect a PC terminal to the
			Liebert STS2 to locate the exact cause. See 12.0 - Communication
			Interfaces for PC terminal commands.
H	Green	Push button to select Source 1	A green LED is lit if the button has been pushed to set Source 1 as
		as the preferred source	the preferred source.
I	Green	Push button to select Source 2	A green LED is lit if the button has been pushed to set Source 2 as
		as the preferred source	the preferred source.
J	Green	Output power is present	A green LED is lit to indicate that power is present on the output
			load.
			Push this button to turn off the horn that is sounded for an alarm.
K		Alarm silence button	This button does not reset an alarm condition, unless pushed
			simultaneously with “M” button.
		Symbol to indicate the K and M
L		must be pushed at the same
		time to reset alarm
			Push this button simultaneously with the “K” button to reset an alarm
M		Alarm reset push button	condition. An alarm can only be reset if the hardware condition
			permits a reset.
			A red LED is lit when an alarm condition is present in the Liebert
			STS2.
N	Red	Alarm present	Connect a PC terminal to the Liebert STS2 to locate the exact
			cause. See 12.0 - Communication Interfaces for PC terminal
			commands.
1	Green	CB1 closed	A green LED is lit if CB1 is closed, indicating power is flowing to the
			static transfer switch from Source 1.
2	Green	CB2 closed	A green LED is lit if CB2 is closed, indicating power is flowing to the
			static transfer switch from Source 2.
3	Green	CB3 closed	A green LED is lit if the output breaker/switch is closed.
3A	Green	CB3A closed	A green LED is lit if the output breaker/switch is closed. CB3A is
			installed on units with dual output breakers.
4	Yellow	CB4 closed	A yellow LED is lit if the Source 1 bypass breaker/switch is closed.
5	Yellow	CB5 closed	A yellow LED is lit if the Source 2 bypass breaker/switch is closed.

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