Liebert Rack Enclosure With Integrated Liquid Cooling XDK-W - Handbuch (Seite 17)

CoolTherm
Manual / Bedienungsanleitung
CoolTherm 01_998_330_0_k page / Seite 15/83
3.5 Control
The server cabinet temperature is controlled by the fan control board VR 2.2. A air temperature
sensor continuously measures the temperature of the server cabinet (server feed air). The air
circulation flow rate is controlled by the fan speed according to the current thermal load.
At temperatures lower than 20°C / 68°F fans rotate at 75% of maximum speed.
Between 20°C / 68°F and 23°C / 73,4°F speed increases proportional to the temperature up to
96% of maximum speed.
The failure of the temperature sensor set the fans to maximum speed.
PDU – Box*)
*) by 12 kW rack
under the roof
CoolTherm front view
The water flow rate is controlled by a three-way valve depending on thermal load. (distribution flow
control) Before all a undertemperature at part load operation can be avoided.
By using a blind sieve in the bypass a hydraulic volume control could be achieved
(two way valve function).
In case of failure the valve opens and the all the chilled water flows through the heat exchanger.
From 16°C / 60,8°F to 19°C / 66,2°F the three-way valve controls the water flow rate from 0% to
100% of the nominal flow rate.
Air temperature
sensor
Status LED:
Green
System OK
Yellow
fault controller
cooling/fans or
rear door open
Red
fault controller
cooling/fans and
rear door open
Space for
optional
equipment
Fuses for each
fan and
switching power
supply
Service socket
and fuse