Control - Knurr CoolServe Betriebsanleitung

CoolServe
Manual / Bedienungsanleitung
3.5

Control

The temperature control is achieved by the fan control board VR 2.2.
An air temperature sensor continuously measures the temperature of the CoolServe air output
side. 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.
The water flow rate is controlled by an two way valve depending on thermal load.
Before all a undertemperature at part load operation can be avoided.
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 valve controls the water flow rate from 0% to 100% of the
nominal flow rate.
The programming of the control is factory preset and password protected.
The failure of the temperature sensor or one of the fans set an alarm using a potential free contact.
Following alarms can be also provided to potential free contacts:
- control failure fan malfunction
- high temperature (two levels)
fan control characteristic (example)
CoolServe
Start at 20°C
air inlet
temperature
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