Airedale OnRak 3kW 35kW - Manual (Page 49)

IT Cooling LogiCool
™ OnRak
IT Cooling
49
Technical, Installation and Maintenance Manual :6912497 V1.5.0 02_2013
Load Neutral Mode
When operating in load neutral mode, the unit ensures the “Air On”/room temperature is modulated to maintain the valve
temperature setpoint. In this condition the air temperature leaving the OnRak is less than the air temperature entering the
server cabinet.
This mode of temperature control considers the impact of case heat radiation as well as the effect of other equipment on
the surrounding environment. Using the OnRak in load neutral mode reduces the cooling capacity as the OnRak tries to
maintain a room setpoint and operates in a similar manner to a CRAC unit.
Server Air Off Temperature Sensors
regulate the fan speed to maintain a
constant cabinet temperature of 40°C
Remote Room Air
Temperature
Sensor
Air Off Temperature is used
to maintain the Room Air
Temperature by modulating
the 3-way valve to adjust the
flow of water through the coil
Heat lost to air
AIR OFF
18˚C
ROOM
AIR TEMP
20˚C
Server
Air Off
Sensor
No. 1
Server
Air Off
Sensor
No. 2
Server
Air Off
Sensor
No. 3
Server
Air Off
Sensor
No. 4