Emerson Liebert Deluxe System/3 DH - Manual (Page 9)

Introduction
1
1.0 I
NTRODUCTION
1.1 System Description
Liebert Deluxe environmental control systems are available in several configurations. Each configu-
ration can operate with either Advanced Microprocessor Controls (AM), or Advanced Microprocessor
Controls with Graphics (AG). A brief description of each, including operational differences, are listed
below. Check model numbers to see what is supplied with your unit.
1.1.1 Compressorized Two-Step Systems
These systems may be air, water, or glycol cooled - depending on the heat rejection method selected.
Cooling
Two stages of mechanical refrigeration
Heating
Three stages of electric reheat standard; steam/hot water, hot gas on water and glycol-cooled systems
optional
Humidification
Infrared standard, steam grid and steam generating optional
Dehumidification
Utilizes the lag compressor
1.1.2 Compressorized Four-Step Systems
The 4-stage systems have all the features of a compressorized 2-stage system plus cylinder unloaders
on one head of each compressor. This permits the compressors to operate at a reduced level and
increases energy efficiency during low load conditions. The system responds to an increasing room
load with either a two step or a four step process of increasing the unit's cooling.
Cooling
Four stages of mechanical refrigeration:
1. Lead compressor at reduced capacity.
2. Lead and lag compressors at reduced capacity.
3. Lead compressor at full capacity; lag compressor at reduced capacity.
4. Lead and lag compressors at full capacity.
Heating
Three stages of electric reheat standard; hot water/steam optional
Humidification
Infrared standard, steam grid and steam generating optional
Dehumidification
Utilizes the lag compressor