Emerson VH User Manual

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.

These systems may be air, water, or glycol cooled - depending on the heat rejection method selected.

Two stages of mechanical refrigeration

Three stages of electric reheat standard; steam/hot water, hot gas on water and glycol-cooled systems 

optional

Infrared standard, steam grid and steam generating optional

Utilizes the lag compressor

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.

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.

Three stages of electric reheat standard; hot water/steam optional

Infrared standard, steam grid and steam generating optional

Utilizes the lag compressor