Airedale OnRak 3kW 35kW - Manual (Page 50)

LogiCool
™ OnRak
Active Cabinet Exhaust
IT Cooling
50
IT Cooling
Technical, Installation and Maintenance Manual :6912497 V1.5.0 02_2013
Rack Pressure Management
The fans will operate to maintain the “air off” temperature as long as the pressure remains within the normal operating
range. However, if the pressure within the server space changes beyond the high or low differential set-points, the fans
prioritise pressure control to bring the server pressure back within limits, at which point normal temperature control
resumes.
The diagram shows the normal operating area between the dotted lines (B) of the low and high set-point differentials.
The red zones (A and C) indicate areas where the fans prioritise pressure control to bring it back within limits.
100%
Fan
Speed
-100%
Fan Minimum
Speed
Low Set-point
(-40Pa)
Low Set-point
Differential
(-30Pa)
High Set-point
Differential
(0Pa)
High Set-point
(10Pa)
Fan
Speed
Fan Maximum
Speed
Temperature control is
affected as the fan speed is
increased to control pressure
0% 0%
Normal operating
range which is not
influenced by
pressure control
Temperature control is
affected as the fan speed is
reduced to control pressure
A B C