FRIULAIR PURESTREAM CWB FC, User And Maintenance Manual

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7425MUM661 Model: CWB FC - Use and Maintenance Manual Rev02
7
SAFETY DEVICES
CWB FC chillers have a series of safety devices that limit the machine's temperature and
pressure values to ensure that it operates within the anticipated limits and to avoid
dangerous situations.
Here is a list of dangerous situations, including the relative safety device and its location.
Dangerous situation Safety device Location
High condensation pressure High-pressure pressure switch Compressor output pipe
High condensation pressure
High-pressure prevention
system
Electronic controller
Low evaporation pressure
Low-pressure pressure
transducer
Compressor intake pipe
Low evaporation pressure
Low-pressure prevention
system
Electronic controller
Low water flow-capacity
Water differential pressure
switch
Plate evaporator
Low water temperature Anti-freeze thermostat Water exit from evaporator
Frequent compressor start-ups Anti-circulation timer Electronic controller
When they reach their set value, most of the security devices trigger an alarm managed by
the electronic controller.
For some safety devices, once the cause of the alarm times out, the machine
resumes operation automatically as soon as the reset value is reached. Others must
be manually reset to restart the machine (also see paragraph
5.11 Alarms ).
The following paragraph lists the characteristics of each safety device.
7.1 C
ALIBRATION OF THE SAFETY DEVICES AND TYPE OF REARM
Safety device Intervention value Reset value Type of rearm
High-pressure pressure switch 42 barg // 609 psi 37 barg // 536 psi Manual
High-pressure prevention * 37 barg // 536 psi 35 barg // 507 psi Automatic
Low-pressure pressure
transducer 6,4 barg // 93 psi 7,4 barg // 107 psi Semi-Automatic
Low-pressure prevention 6,9 barg // 100 psi 7,9 barg // 114 psi Automatic
Low-pressure vacuum alarm 5,4 barg // 78 psi 6,4 barg // 93 psi Manual
Water differential pressure
switch 85 mbar // 1,23 psi 105 mbar // 1,52 psi Manual
Anti-freeze thermostat 4°C // 39,2°F 8°C // 46,4°F Semi-Automatic
Anti-circulation timer ** 3 min. --- ---
* Consists in reducing the number of functioning compressors to 1 until the condensation pressure
falls below the reset value again.
** This is a function of the electronic controller that prevents the same compressor from stopping and
starting too frequently: at least 3 minutes must elapse between one compressor’s power up and the
next.