Liebert 100-1000A User Manual

Minimal periodic maintenance of the Liebert STS2 is required. As with all electrical distribution 

components, the system should be regularly inspected for electrical connection integrity, signs of 

excessive temperatures, dirt accumulation, and proper system operation.

The recommended tightening torque for all nuts and bolts is as shown below, unless otherwise 

labeled. All power connections are designed to remain at proper torque throughout the lifetime of the 

unit. 

The Liebert STS2 includes comprehensive system alarms and fault detection to identify operational 

problems. To increase the degree of confidence of proper system operation, periodic transfer tests can 

be easily performed. For instructions for changing the preferred source and switching sources:

• For a Color Graphical Display unit, see 10.2 - Manual Transfer / Preferred Source 

Selection on page 66.

• For an LED-equipped unit, see 14.2.2 - Manual Transfer / Preferred Source Selection on 

A standard furnace filter is installed behind the air intake in the front door. The air intake allows air 

to circulate to cool the unit. Replace the filter when it becomes dirty and impedes air flow. The 

frequency of changing or cleaning the filter depends on the location in which the unit is located.
The size of the filter is 1 in. x 25 in. x 25 in. (2.54 cm x 63.5 cm x 63.5 cm).

Only qualified service personnel should perform maintenance on the static switch.
Lethal voltages exist inside the unit during normal operation. 
The unit is supplied by multiple AC power sources. Disconnect and lock-out all power sources 

before working inside unit.

10-32

25

3

35

4

1/4-20

53

6

80

9.0

5/16-18

107

12

180

20.4

3/8-16

192

22

240

27.1

1/2-13

428

48

480

54.3