Liebert iCOM Microprocessor TM-10098 - Manual (Page 12)

iCOM
Control Training and Service Manual
Temperature Control
Operations and Charts
The temperature proportional control band value
is divided into two parts: the
temperature set point plus ½ of the temperature proportional band for cooling
operation and the temperature set point minus ½ of the temperature proportional
band for heating operation. A temperature dead band can also be programmed
into the control to shift the cooling and/ or heating on/ off operations away from the
temperature set point.
This programmed temperature dead band value is divided into two parts: the
temperature set point plus ½ of the dead band – no cooling operation and the
temperature set point minus ½ of the band – no heating operation.
The temperature set point range is adjustable from 41 - 104
°F in increments of
1
°F. The temperature proportional band range is adjustable from 2 - 54°F in
increments of 1
°F. The temperature dead band range is adjustable from 0 - 36°F
in increments of 1
°F.
Standard 2 Stage Compressorized Cooling
The basic temperature cooling control band is established at the temperature set
point with the length equal to ½ of the programmed temperature proportional band
divided by the number of cooling stages.
The Liebert DS units are supplied with two (2) compressors, each compressor is
rated at ½ of the unit capacity. The two (2) compressors will be either the
semi-hermetic or scroll type and will operate in an on/ off configuration to cool the
space.
The temperature controller activates the first cooling stage (lead compressor)
when the return air temperature increases to 50% of the cooling proportional band
and the second cooling stage (lag compressor) at 100% of the cooling proportional
band. The optional hot gas bypass solenoid valve, supplied with each compressor
when ordered, is also energized on a call for cooling.
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