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Model number nomenclature-Evaporator units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Model number nomenclature-Air-cooled, indoor condensing units . . . . . . . . . . . . . . . . . . . . . . . . 3
Model number nomenclature-Outdoor air-cooled prop fan condensing units . . . . . . . . . . . . . . . . 4
Model number nomenclature-Water/glycol-cooled condensing units. . . . . . . . . . . . . . . . . . . . . . . 4
Model number nomenclature-Chilled water units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 6
Wall-box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Free-cooling arrangement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Air-cooled systems, 2 and 3 tons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Water/glycol-cooled systems, 2 and 3 tons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 10 Chilled water systems, 3 tons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 11 Threaded rod and hardware kit installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 12 Refrigerant piping diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 13 Dimensions, evaporator and chilled water units with direct drive blower . . . . . . . . . . . . . . . . . . 24
Figure 14 Dimensions, evaporator units with optional belt drive blower assembly . . . . . . . . . . . . . . . . . . . 25
Figure 15 Evaporator and chilled water unit piping data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 16 Evaporator and chilled water unit electrical connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 17 Close-coupled installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Figure 18 Indoor air-cooled centrifugal condenser dimensions and pipe connections . . . . . . . . . . . . . . . . . . 32
Figure 19 Centrifugal condenser electrical connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 20 Cabinet and floor planning dimensional data, outdoor condensing unit . . . . . . . . . . . . . . . . . . . . 34
Figure 21 General arrangement (air- cooled condensing unit) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Figure 22 Cabinet dimensions and piping data, water/glycol indoor condensing module . . . . . . . . . . . . . . . 37
Figure 23 General arrangement, water/glycol split systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Figure 24 Optional free-cooling coil (3-way valve) on water/glycol units . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Figure 25 Optional hot water reheat (two-way valve) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Figure 26 Control key locations-all-mounted display box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Figure 27 Control menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Figure 28 Control board (inside evaporator) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Figure 29 Wall box board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Figure 30 Ground current detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Figure 31 Hot gas bypass. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
FIGURES
iv
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Troubleshooting
Need help?
Do you have a question about the Mini-Mate2 MMD24E and is the answer not in the manual?
Questions and answers
Low suction & head pressure w/ glycol system & free cooling. Inlet cooling water 56 degrees, 10# diff. press, recovered refrigerant & weighed in proper charge 96oz.
Low suction and head pressure in a Liebert Mini-Mate2 MMD24E with a glycol system and free cooling could be caused by:
1. Low Glycol Solution Level – Insufficient glycol in the system can reduce heat transfer efficiency.
2. Improper Glycol Concentration – Incorrect glycol mixture can affect system performance.
3. Low Water/Glycol Temperature – If the temperature is too low, the free-cooling coil may take over, reducing suction and head pressure.
4. Restricted Flow in the System – Blockages or closed valves in the glycol piping can limit circulation.
5. Malfunctioning Three-Way Valve – If the free-cooling valve does not function correctly, it may divert flow improperly.
6. Dirty or Clogged Coil – A buildup of debris on the free-cooling coil can restrict heat exchange.
7. Air in the System – Entrapped air can reduce efficiency and cause pressure issues.
8. Pump Issues – A faulty or improperly sized pump may not circulate glycol effectively.
Checking glycol levels, valve operation, and system cleanliness can help diagnose the issue.
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