Operation
Liebert
®
CRV
™
154
Reheating
—Electrical heating (optional): The heating elements heat the air passing over them
during dehumidifcation. The heating control is active only when the unit is in dehumidification mode.
The reheats will only activate when the unit is dehumidifying. The reheats will begin activation when
the control temperature has dropped to -66% of the control's proportional band and will deactivate
when temperature setpoint has been reached.
Dehumidification
(DX mode)—The temperature of the cooling coil is reduced to remove moisture
from the air (refer to Service menus-Setpoints parameters screen - Page 2, Service menus-Setpoints
parameters screen - Page 3, Service menus-Diagnostics / service mode parameters screen - Page 3 and
Service menus-Opt).
• In dehumidification mode, the air after passing over the coil is reheated (if needed) by electrical
heaters to stabilize the initial temperature.
Humidification
(optional)—The humidifier creates steam, which is distributed into the air stream
via the steam distribution pipe. (See also
Appendix A - Humidifier—600mm (24") Units Only
).
The Liebert CRV's humidification is activated when the measured temperature and humidity sensor
has been calculated to exceed the corresponding dew point setpoint. The dew point setpoint is
calculated based on the temperature and humidity of the sensor set to control the control setpoint and
relative humidity.
Example: Temperature Setpoint 72°F / Humidity Setpoint 50% = 52°F Dew Point
The status of the humidifier lockout can be viewed in the Service/Diagnostics menu.
These protections do not apply to the external humidifier output.
NOTE
If dehumidification cannot reach its setpoint within a set amount of time, the unit will delay
dehumidification to allow the room temperature to stabilize.
NOTE
The Liebert iCOM
®
control monitors the condition of the air discharging from the unit to
protect neighboring electronic equipment. Liebert iCOM will prevent the humidifier from
activating if the discharge air is near its saturation point. This protects against discharging
fog from the unit or condensation forming on the unit's supply air baffles. This protection mode
is activated when the supply sensor reading is below 53°F (11.7°C) or above 55% relative
humidity. When this condition is met a message will display showing “humidifier” suspended.