USER and
MAINTENANCE
MANUAL
25
10.2 VERIFICATIONS DURING OPERATION
>
Check that the sequence of the phases is correct� This can be verified by making sure that the supply
pressure increases and the intake pressure decreases when the compressor is started up� Otherwise,
the phase sequence is incorrect and the compressors are rotating in the wrong direction; it is therefore
important to quickly restore the correct phase sequence� If the compressor is repeatedly started up
and shut down in the wrong direction, and the phase sequence is not corrected, the compressor will
be permanently damaged�
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Check that the evaporator inlet water temperature is near to the unit control set value�
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For the unit is supplied with pump unit, if the pump should be noisy, close the flow cock until normal
functioning has been restored� This can occur when the pressure drop in the system is largely offset
from the pump static pressure�
CALIBRATING THE CONTROL COMPONENTS
The control equipment is entirely calibrated and tested in the factory before the unit is shipped� However,
after the unit has been working for a reasonable period of time, the safety devices should be checked�
The calibration settings are shown in Table 2�
11
The control equipment should be serviced by qualified staff only.
Incorrect calibration settings can cause serious damage to the unit and
injuries to people.
Control and safety components Activation set point
Differential
Reset
Safety valve setting
30�0 bar
-
-
High pressure switch setting
27�5 bar
4
(Controller) manual
Low pressure switch setting
1�5 bar
1
(Controller) manual
Anti-freeze alarm setting
-15 °C
6 °C
(Controller) manual
Evaporator heater setting
5 °C
1 °C
Automatic
Leak detector R290
5% LEL
Manual
10.3 CHECKING THE REFRIGERANT LOAD
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Check, after a few hours of operation, that the liquid warning light is green: if it is yellow, there is humi-
dity in the circuit� In this case, the circuit must be dried by qualified personnel�
>
Check that bubbles do not appear at the liquid indicator� The continuous passage of bubbles can in-
dicate the lack of refrigerant and the need for top-up� The presence of just a few bubbles is permitted,
however, especially when the compressor is working at a rate other than the nominal one�
10.4 ALARMS
Repeatedly resetting the alarms without understanding and resolving
the problems that have caused the alarms could permanently damage
the machine. Always contact the technical assistance service when an
alarm occurs!
Summary of Contents for PURPLE
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