Emerson Liebert iCOM, Manual

Page: 120 / 172

Service Menu Parameters
Liebert
®
iCOM
®
for Liebert DSE
™
112
S153 Fanspeed Dehum/No Power —Sets the fan speed when a call for dehumidification is active.
This allows the units fan speed to be ramped lower to help with any overcooling due to the
dehumidification process. This also allows the coil to remove additional moisture even faster.
S154 Allow Fan Modulation on Comp —Provides the option to set the fan to fixed speed if the unit
is equipped with compressors. Two options are available: No and Yes (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 to re-engage fan speed control.
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. The options are:
Disabled, Local (default) and Team.
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 potentially cause degradation of the compressor oil,
that could decrease the overall compressor life expectancy.
S15B Return Limit P-Band —Sets the rate of fanspeed increase as the actual return temperature
approaches the limit set in the High Return Temperature Limit parameter.
Figure 87 Setpoints screen, page 6 of 9
S158 Fanspeed Filter at 0-100% —This parameter should only be adjusted by a factory service
trained 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 service
trained technician. The transition fan speed filter controls how quickly the fan speed changes
between different modes of operation. For example, if the fans are operating based on a call for reheat
which is normally 100% fan speed and the reheats are turned Off or no longer needed then the fan
speed would instantly change if this filter is not applied, which may cause instability in the fan speed
control. This filter helps with the transition to avoid overshoot.