High Static Belt Drive Blower Package (Option); Refrigeration System; Table 28 External Static Pressure Available; Table 29 Typical Discharge Pressure - Liebert Mini-Mate2 MMD24E User Manual

9.2.4

High Static Belt Drive Blower Package (Option)

The High Static Blower option is a belt-driven blower box that is attached to the evaporator box. Belt
drive should be checked monthly for signs of wear and proper tension. The motor sheave should be
adjusted per the following chart.
Table 28 External static pressure available
Sheave
Turns RPM
5 1450
4.5 1510
4 1570
3.5 1630
3 1690
2.5 1750
2 1810
1.5 1870
1 1930
0.5 1990
0 2050
9.2.5

Refrigeration System

Each month the components of the refrigeration system should be inspected for proper function and
signs of wear. Since in most cases evidence of malfunction is present prior to component failure,
periodic inspections can be a major factor in the prevention of most system failures. Refrigerant lines
must be properly supported and not allowed to vibrate against ceilings, floors, or the unit frame.
Inspect all refrigerant lines every six months for signs of wear and proper support. Inspect the
capillary and equalizer lines from the expansion valve.
Suction Pressure
Suction pressure will vary with load conditions. Suction pressure normally ranges from 58psi to 75psi
(405kPa to 517kPa).
Discharge Pressure
The discharge pressure will vary greatly with load and ambient conditions (see Table 29). The high-
pressure switch will shut the compressor down at its cut-out setting
Table 29 Typical discharge pressure
System Design
Air-Cooled
Water-Cooled 65 to 85°F water
(18 to 29.4°C)
Glycol-Cooled
High-Pressure Cut-Out
Thermostatic Expansion Valve
The thermostatic expansion valve keeps the evaporator supplied with enough refrigerant to satisfy
load conditions. Proper valve operation can be determined by measuring superheat level. If too little
refrigerant is being fed to the evaporator, then the superheat will be high. Conversely, if too much
refrigerant is being supplied, then the superheat will be low. The correct superheat setting is between
10 and 15°F (5.6 and 8.3°C).
2-Ton Units @
885 CFM (1504 CMH)
ESP
in. (mm)
1.0 (25.4)
1.1 (28.8)
1.3 (32.4)
1.4 (36.1)
1.6 (40.0)
1.7 (44.0)
1.9 (48.1)
2.1 (52.4)
2.2 (56.8)
2.4 (61.3)
2.6 (66.0)
Discharge Pressure, psig (kPa)
200-300 (1380-2070)
200-250 (1380-1725)
250-350 (1725-2415)
3-Ton Units @
1250 CFM (2124 CMH)
ESP
in. (mm)
0.4 (10.2)
0.5 (13.6)
0.7 (17.2)
0.8 (20.9)
1.0 (24.7)
1.1 (28.7)
1.3 (32.8)
1.5 (37.1)
1.6 (41.5)
1.8 (46.1)
2.0 (50.8)
400 (2760)
61
System Testing and Maintenance
®
Liebert Mini-Mate2
™