17
Cooling
HP/LP switches
The condensing unit HP and LP switches are located in the right-hand end of the housing. The device has been pre-set to the
conditions specified below.
Low pressure setting
On the suction side of the compressor, the low pressure settings stop the compressor when the pressure gets too low (lower
set-point) and restarts the compressor once the pressure has risen back to the upper set-point. These are managed by the
mechanical switch as an upper set-point and a differential setting, as below.
Lower set-point (cut-out pressure) = Upper set point (cut-in pressure) – differential.
The default settings are as below:
• Upper set-point = 5 barg
• Differential = 3 barg
This gives a default lower set-point of 2 barg.
High pressure setting
On the discharge side of the compressor, there is a high pressure trip which prevents the compressor from over-pressuring the
system. This will stop the compressor if the pressure gets too high and is set to the below set-point by default:
• High pressure trip setting = 25 barg
The high pressure switch has an automatic reset, which is set to restart the compressor at 4 barg below the trip pressure.
This differential is not adjustable.
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