Emerson Liebert PEX 1020FA/W/G User manual

i
TABLE OF CONTENTS
IMPORTANT SAFETY INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.0 LIEBERT PEX COMPONENTS AND NOMENCLATURE
2.0 COOLING CONFIGURATIONS
3.0 PRE-INSTALLATION GUIDELINES
3.1 Room Preparation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Air Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2.1 Downflow Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2.2 Upflow Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3 Location Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.4 Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.0 LIEBERT PEX DIMENSIONS AND WEIGHTS
5.0 EQUIPMENT INSPECTION AND HANDLING
5.1 Packaging Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.2 Unpacking the Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.2.1 Removing the Unit from the pallet With a Forklift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.2.2 Moving the Unit to the Installation Location with Piano Jacks . . . . . . . . . . . . . . . . . . . . . . . 24
5.2.3 Removing Piano Jacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.2.4 Removing Liebert PEX from pallet Using Rigging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.3 Placing the Unit on a Floor Stand. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.3.1 Downflow Chilled Water Units with EC Fan Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6.0 ELECTRICAL CONNECTIONS
6.1 Electrical Field Connection Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
6.1.1 Water Under Floor Sensor (LWD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
6.1.2 Remote Air Cooled Condenser Power Kit Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
6.1.3 iCOM Network Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
6.1.4 IntelliSlot 485 and WEB/SNMP Cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

ii
7.0 PIPING
7.1 Fluid Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
7.1.1 Condensate Piping—Field-Installed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
7.1.2 Humidifier Supply Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7.1.3 Requirements of Systems Using Water or Glycol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7.2 Refrigeration Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
7.2.1 Piping Guidelines—Air-Cooled Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
7.2.2 Piping Guidelines - Chilled Water units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
7.3 Dehydration/Leak Test and Charging Procedures for R-407C and R-22 . . . . . . . . . . . . . . . 42
7.3.1 Air Cooled Condenser with Electronic Fan Speed Head Pressure Control System . . . . . . . . 42
8.0 PIPING SCHEMATICS
9.0 CHECKLIST FOR COMPLETED INSTALLATION
9.1 Moving and Placing Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
9.2 Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
9.3 Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
9.4 Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
10.0 INITIAL STARTUP CHECKS AND COMMISSIONING PROCEDURE FOR WARRANTY INSPECTION
10.1 Information for Warranty Inspection—Remove Power From Unit Input Isolator. . . . . . . . 68
10.2 Startup Checks Inspection With Panels Removed and Input Isolator Switch Off . . . . . . . . 69
10.3 Commissioning Procedure With Panels On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

iii
11.0 MAINTENANCE
11.1 Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
11.1.1 Filter Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
11.2 Blower System - Belt Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
11.2.1 Belt Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
11.2.2 Belt Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
11.3 Blower System - Direct Drive (EC Fans) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
11.3.1 Removal - Downflow Chilled Water Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
11.4 Infrared Humidifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
11.4.1 Cleaning Humidifier Pan and Float Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
11.4.2 Changing Humidifier Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
11.5 Immersed Electrode Humidifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
11.5.1 Cleaning Humidifier Bottle, Electrodes and Steam Pipe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
11.6 Condensate Drain and Condensate Pump Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
11.6.1 Condensate Drain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
11.6.2 Condensate Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
11.7 Air Cooled Condenser and Drycoolers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
11.8 Reheat—Electric Reheat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
11.9 Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
11.9.1 Compressor Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
11.9.2 Scroll Compressors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
11.10 Compressor Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
11.10.1 Compressor Motor Burnout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
11.10.2 Compressor Replacement Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
11.11 Facility Fluid and Piping Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
11.12 Plate Heat Exchanger—Water Cooled Condenser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
12.0 HVAC MAINTENANCE CHECKLIST

iv
LIST OF FIGURES
Figure 1 Downflow model component locations, air/water/glycol cooled systems . . . . . . . . . . . . . . . . . . . . . 3
Figure 2 Upflow model component locations - air/water/glycol/chilled water systems . . . . . . . . . . . . . . . . . 4
Figure 3 Downflow model component locations - chilled water EC fan systems . . . . . . . . . . . . . . . . . . . . . . 5
Figure 4 Upflow model component locations - chilled water EC fan systems . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 5 Liebert PEX model number nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 6 Cabinet and floor planning dimensional data - 1 bay downflow, large frame models . . . . . . . . . 10
Figure 7 Cabinet and floor planning dimensional data - 2 Bay downflow, large frame models . . . . . . . . . 11
Figure 8 Cabinet and floor planning dimensional data - 3 bay downflow, large frame models . . . . . . . . . 12
Figure 9 Cabinet and floor planning dimensional data - 1 bay upflow, large frame models. . . . . . . . . . . . 13
Figure 10 Cabinet and floor planning dimensional data - 2 bay upflow, large frame models. . . . . . . . . . . . 14
Figure 11 Cabinet and floor planning dimensional data - 3 bay upflow, large frame models. . . . . . . . . . . . 15
Figure 12 Cabinet and floor planning dimensional data - 1 bay downflow, large frame EC fan models . . . 16
Figure 13 Cabinet and floor planning dimensional data - 2 bay downflow, large frame EC fan models . . . 17
Figure 14 Cabinet and floor planning dimensional data - 3 bay downflow, large frame EC fan models . . . 18
Figure 15 Cabinet and floor planning dimensional data - 1 bay upflow, large frame EC fan models . . . . . 19
Figure 16 Cabinet and floor planning dimensional data - 2 bay upflow, large frame EC fan models . . . . . 20
Figure 17 Cabinet and floor planning dimensional data - 3 bay upflow, large frame EC fan models . . . . . 21
Figure 18 Equipment recommended for handling Liebert PEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 19 Removing packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 20 Floor Stand Arrangement - Downflow units, forward curve fan . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure 21 Floor Stand Arrangement - Downflow chilled water units (EC fan option) . . . . . . . . . . . . . . . . . 26
Figure 22 Minimum clearance requirements for EC Fan Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 23 Installation handle fixing locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 24 Lowering EC fan motor into operating position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 25 Floorstand orientation & base plate fixing details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 26 Upflow ducting configurations - forward curve fan systems, type D air path . . . . . . . . . . . . . . . . 29
Figure 27 Duct connection details - forward curve fan systems, type D air path . . . . . . . . . . . . . . . . . . . . . 30
Figure 28 Duct connection details - backward curve(EC) fan systems, type V air path . . . . . . . . . . . . . . . . 31
Figure 29 Plenum discharge details - forward curve fans, type U and V air path. . . . . . . . . . . . . . . . . . . . . 32
Figure 30 Electrical panel general arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 31 Field connection terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 32 Water Under Floor Sensor (LWD) wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Figure 33 Piping schematic - air cooled, scroll compressor models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Figure 34 Piping schematic - water/glycol, scroll compressor models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Figure 35 Piping schematic - chilled water models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Figure 36 Primary connection locations - 1 bay downflow, air/water/glycol cooled, single scroll compressor,
forward curve fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Figure 37 Primary connection locations - 2 bay downflow, air/water/glycol cooled, single scroll compressor,
forward curve fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Figure 38 Primary connection locations - 2 bay downflow air/water/glycol cooled, dual scroll compressor mod-
els, forward curve fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Figure 39 Primary connection locations - 3 bay downflow, air/water/glycol cooled, dual scroll compressor, for-
ward curve fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Figure 40 Primary connection locations - 1 bay upflow, air/water/glycol cooled, single scroll compressor mod-
els, forward curve fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Figure 41 Primary connection locations - 2 bay upflow, air/water/glycol cooled, single scroll compressor mod-
els, forward curve fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Figure 42 Primary connection locations - 2 bay upflow, air/water/glycol cooled, dual scroll compressor models,
forward curve fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

v
Figure 43 Primary connection locations - 3 bay upflow, air/water/glycol cooled, dual scroll compressor models,
forward curve fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Figure 44 Primary connection locations - 1 bay downflow, chilled water, forward curve fan . . . . . . . . . . . . 55
Figure 45 Primary connection locations - 2 bay downflow, chilled water, forward curve fan . . . . . . . . . . . . 56
Figure 46 Primary connection locations - 3 bay downflow, chilled water, forward curve fan . . . . . . . . . . . . 57
Figure 47 Primary connection locations - 1 bay upflow, chilled water, forward curve fan . . . . . . . . . . . . . . 58
Figure 48 Primary connection locations - 2 bay upflow, chilled water, forward curve fan . . . . . . . . . . . . . . 59
Figure 49 Primary connection locations - 3 bay upflow, chilled water, forward curve fan . . . . . . . . . . . . . . 60
Figure 50 Primary connection locations - 1 bay downflow, chilled water, EC fan . . . . . . . . . . . . . . . . . . . . . 61
Figure 51 Primary connection locations - 2 bay downflow, chilled water, EC fan . . . . . . . . . . . . . . . . . . . . . 62
Figure 52 Primary connection locations - 3 bay downflow, chilled water, EC fan . . . . . . . . . . . . . . . . . . . . . 63
Figure 53 Primary connection locations - 1 bay upflow, chilled water, EC fan . . . . . . . . . . . . . . . . . . . . . . . 64
Figure 54 Primary connection locations - 2 bay upflow, chilled water, EC fan . . . . . . . . . . . . . . . . . . . . . . . 65
Figure 55 Primary connection locations - 3 bay upflow, chilled water, EC fan . . . . . . . . . . . . . . . . . . . . . . . 66
Figure 56 Proper filter pleat direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Figure 57 Fan Belt Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Figure 58 EC Fan motor removal procedure - handle fixing location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Figure 59 EC fan motor removal procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Figure 60 Correct orientation of float switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Figure 61 Infrared humidifier lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Figure 62 Immersed electrode humidifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Figure 63 Electrode orientation for different water qualities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

vi
LIST OF TABLES
Table 1 Weights for 1 bay downflow, large frame models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Table 2 Weights for 2 bay downflow, large frame models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 3 Weights for 3 bay downflow, large frame models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Table 4 Weights for 1 bay upflow, large frame models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 5 Weights for 2 bay upflow, large frame models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 6 Weights for 3 bay upflow, large frame models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 7 Weights for 1 bay downflow, large frame EC fan models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 8 Weights for 2 bay downflow, large frame EC fan models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 9 Weights for 3 bay downflow, large frame EC fan models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table 10 Weights for 1 bay upflow, large frame EC fan models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Table 11 Weights for 2 bay upflow, large frame EC fan models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Table 12 Weights for 3 bay upflow, large frame EC fan models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Table 13 Recommended refrigerant line sizes - OD copper mm (inches) . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Table 14 Indoor unit approximate refrigerant charge for R-22 or R-407C . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Table 15 Liquid Line charges - refrigerant per 30m (100 ft) of Type “L” copper tube . . . . . . . . . . . . . . . . . 40
Table 16 Base Charge Limit for Air Cooled Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Table 17 Outdoor condenser approximate refrigerant charge kg (lb) per circuit . . . . . . . . . . . . . . . . . . . . . 41
Table 18 Filter quantities, downflow units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 19 Filter quantities, upflow units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 20 Compressor oil types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Table 21 Guide to resistance of copper and AISI 316 stainless steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

1
IMPORTANT SAFETY INSTRUCTIONS
SAVE THESE INSTRUCTIONS
This manual contains important safety instructions that should be followed during the installation
and maintenance of the Liebert PEX. Read this manual thoroughly before attempting to install or
operate this unit.
Only qualified personnel should move, install or service this equipment.
Adhere to all warnings, cautions and installation, operating and safety instructions on the unit and in
this manual. Follow all operating and user instructions.
!
WARNING
Risk of electric shock. Can cause injury or death.
Disconnect local and remote power supplies before working within.
Before proceeding with installation, read all instructions, verify that all the parts are included
and check the nameplate to be sure the voltage matches available utility power.
The iCOM microprocessor does not isolate power from the unit, even in the “unit off” mode.
Some internal components require and receive power even during the “unit off” mode of iCOM
control.
The PEX unit isolation switch is inside the unit. The line side of this switch contains live high
voltage.
The only way to ensure that there is NO voltage inside the unit is to install and open a remote
isolation switch. Refer to unit electrical schematic.
Follow all local codes.
!
WARNING
Risk of explosive discharge from high-pressure refrigerant. Can cause injury or death.
This unit contains fluids and gases under high pressure. Relieve pressure before working with
piping.
!
WARNING
Risk of refrigerant system rupture or explosion from overpressurization. Can cause
equipment damage, injury or death.
NOTE
The Liebert PEX indoor cooling unit has a factory-installed high pressure safety switch in the
high side refrigerant circuit.
!
WARNING
Risk of high-speed moving parts. Can cause injury or death.
Disconnect all local and remote electric power supplies before working in the unit.
!
CAUTION
Risk of contact with hot surfaces. Can cause injury.
The compressors, refrigerant discharge lines, humidifiers and reheats are extremely hot
during unit operation. Allow sufficient time for them to cool before working within the unit
cabinet. Use extreme caution and wear protective gloves and arm protection when working on
or near hot compressors, discharge lines, humidifiers and reheats.

2
!
CAUTION
Risk of leaking water. Can cause equipment and building damage.
This unit requires a water drain connection. It also requires an external water supply to
operate.
Improper installation, application and service practice can result in water leakage from the
unit. Water leakage can result in severe property damage and loss of critical data center
equipment.
Do not locate unit directly above any equipment that could sustain water damage.
Emerson recommends installing leak detection equipment for unit and supply lines.

Liebert PEX Components and Nomenclature
3
1.0 LIEBERT PEX COMPONENTS AND NOMENCLATURE
Figure 1 Downflow model component locations, air/water/glycol cooled systems
2
5
8
3
1
4
7
10
11
12
6
9
1. iCOM Control Display
2. Filters
3. Evaporator Coil
4. Electrical Panel
5. Input Isolator
6. Infrared Humidifier
7. Fan Motor
8. Fan Pulley
9. Compressor
10. Condensate Pump (optional)
11. Water Cooled Condenser
12. Water regulating Valve