Control - Knurr CoolTherm Bedienungsanleitung

CoolTherm
Manual / Bedienungsanleitung
3.5

Control

The server cabinet temperature is controlled by the fan control board VR 2.2. An 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.
figure CoolTherm front view
The water flow rate is controlled by an optional 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 (option) 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 optional three-way valve controls the water flow rate from
0% to 100% of the nominal flow rate.
CoolTherm
Air temperature
sensor
PDU – Box*)
*) by 12 kW rack
under the roof
01_998_330_0_m
Status LED:
Green
System OK
Yellow
fault controller
cooling/fans or
rear door open
Red
fault controller
cooling/fans and
rear door open
Fuses for each
fan and
switching power
supply
Space for
optional
equipment
Service socket
and fuse
page / Seite 16/157