User's Manual

Service Menu Parameters
Liebert
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iCOM
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128
S153 Fanspeed Dehum/No Power—Sets the fan speed when a call for dehumidification is active.
This allows the unit’s fan speed to be reduced to help with any overcooling due to dehumidification.
This also allows the coil to remove additional moisture faster.
S154 Allow Fan Modulation on Comp—Permits setting the fan to fixed speed if the unit is
equipped with compressors. Two options are available: No, Yes (factory default).
• No: Sets the fans speed to S152 STD speed during compressor operation. Once this parameter is
set at the local display, it must be removed at the local display before fan speed control can be
re-engaged.
• Yes: Allows the fan speed to modulate during compressor operation according to the programmed
fan control settings.
S155 High Return Limit Enable—Sets a control point that will increase the fan speed if the return
temperature exceeds the limit set in the High Return Temperature Limit parameter. Three options
are available:
• Disabled: The high return limit is disabled.
• Local: This setting uses the unit’s factory-installed return air temperature sensor for applying the
limit.
• Team: Applied in U2U networks only. Allows the high return limit to be applied to all units in the
group based on the highest return temperature sensed by all connected and operating units.
Values are hidden when the fan control sensor is set for return.
S15A High Return Temperature Limit—Sets the temperature limit that will increase the fan
speed to decrease the return temperature. Some compressors may require this limit to prevent
extremely high return temperatures that could degrade the compressor oil, which could decrease the
compressor life expectancy.
S15B Return Limit P-Band—Sets the rate of fan speed increase as the actual return temperature
approaches the limit set in the High Return Temperature Limit parameter.
Figure 111 Setpoints screen, page 6 of 10
S158 Fanspeed Filter at 0-100%—This parameter should be adjusted only by a factory-trained
service technician. Fan Cap Filter at 0% / 100% controls the rate of change during fan speed changes
to avoid overshoots. The filter value depends on the current control deviation from the setpoint. On
the setpoint (at 0%), it’s typically set lower (slow), and at the end of the P-band (at 100%) it’s typically
set higher (faster). The value is given in % control output change per second. This parameter sets the
rate of change based on where actual temp is when compared to setpoint.
S159 Fanspeed Transition Filter—This parameter should only be adjusted by a factory-trained
service technician. The transition fan speed filter controls how quickly the fan speed changes between