Emerson Liebert iCOM, Manual

Page: 64 / 172

Operation
Liebert
®
iCOM
®
for Liebert DSE
™
56
3.8.7 Liebert EconoPhase (Full / Partial)
Before the Liebert DSE can switch from compressor operation to EconoPhase operation, the following
conditions must be met:
• Liebert iCOM startup test
• Communication with the Liebert EconoPhase control board established
• Communication with the Liebert MC control board established
• Communication with the EEV control board established
Once the conditions above are satisfied, the Liebert iCOM will determine whether the outdoor dry
bulb conditions are low enough to provide enough cooling to maintain the indoor room load. Dry bulb
conditions must be either:
• 32°F (0°C) or lower
or
• 5°F (-15°C) lower than the return temperature.
The transition to Mixed Mode can be from either full Compressor Mode or full EconoPhase Mode.
Mixed Mode operation is based on the outdoor minimum criteria mentioned above. The Liebert iCOM
uses proprietary calculations to determine how much compressor capacity is required to maintain
room temperature as heat load and outdoor conditions change. When the Liebert DSE is operating in
mixed EconoPhase Mode, the outer coil will always be the Liebert EconoPhase circuit and the inner
coil will always be the compressor operation circuit. EconoPhase operation will be aborted if either of
the following conditions occur:
• Communication to the condenser or pump control board is lost
• Indoor room temperature control cannot be maintained as measured by the supply air sensor
If EconoPhase operation cannot maintain the temperature setpoint or a pump failure occurs,
compressor operation will automatically start to ensure room temperature is maintained. If Liebert
iCOM exits Mixed Mode 10 times because room temperature cannot be maintained with EconoPhase,
an MM Cycle Lock Out warning will occur. Mixed Mode will not resume until the warning has been
acknowledged or the control has rebooted.
Figure 45 Liebert EconoPhase operation
NOTE
When supply air temperature control is used, the supply air temperature minus the outside air
temperature must be greater than 5°F (-15°C) before EconoPhase can be used.
Comp Pump
Mixed Mode
Pump Pump
Full
EconoPhase
Pump Idle
Partial
EconoPhase
Comp Comp
Full DX