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Maintenance
76
7.6 Optional Air Filters
The optional air filters must be inspected and serviced on a regular schedule. The period between
inspections will depend upon environmental conditions. Under normal conditions, the air filters will
require cleaning or replacement approximately every 12 months.
Abnormal or dusty conditions will require more-frequent cleaning and replacement of air filters
(sometimes as often as every two months). Inspect installations in new buildings more often, then
extend the inspection period as experience dictates.
7.7 Torque Requirements
All electrical connections must be tight. Table 12 provides the torque values for the connections in
the Liebert FS. Use these values unless the equipment is labeled otherwise.
7.8 Detecting Trouble
It is important that the operator check the instrument readings if abnormal equipment performance
is suspected. Any metered value that differs appreciably from normal could mean an impending mal-
function and should be investigated.
Items to check include:
• Alarm messages indicate malfunction or impending malfunction. A daily check of the operator
control panel will help to provide an early detection of problems. Refer to Table 16 to interpret
alarm messages.
• Tracing a problem to a particular section is facilitated by alarm messages and the metered
parameter indications. These are stored in the Status Reports and can be displayed at the opera-
tor control panel or at an optional terminal. A Liebert Services engineer will be familiar with test
points inside the unit.
!
CAUTION
Be certain recyclable filter elements are dry before reinstalling them in the Liebert FS.
Table 12 Torque specifications (unless otherwise labeled)
Nut And Bolt Combinations
Bolt Shaft Size
Grade 2
Standard
Electrical Connections
With Belleville Washers
Lb-in N-m Lb-in N-m
1/4 53 6.0 46 5.2
5/16 107 12 60 6.8
3/8 192 22 95 11
1/2 428 48 256 29
Circuit Breakers with Compression Lugs (For Power Wiring)
Current Rating Lb-in N-m
250A 250 28
Circuit Breakers with Compression Lugs (For Control Wiring)
AWG Wire Size or Range Lb-in N-m
#22 - #14 3.5 to 5.3 0.4 to 0.6
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