Galletti LCA 080 - Maximum Pressure Switch; Minimum Pressure Switch; Service Thermostat; Antifreeze Thermostat

LCA
RG66000986 – Rev.00
19
MAXIMUM PRESSURE SWITCH
The high pressure switch is of the manually reset type and classifiable as category IV under EEC 97/23.
It directly stops the compressor when the discharge pressure exceeds the set value.
Warning: do not attempt to change the setting of the pressure switch: should the latter
fail to trip in the event of a pressure increase, the pressure relief valve will open!
To verify its efficiency, while the compressors are running, close off the passage of air into the
condensers and check by referring to the compressor outlet pressure gauge (previously installed)
whether the pressure switch trips (i.e. the compressors stop) when the set value is reached.
Warning: while you are carrying out this check, you should be ready to shut off the unit
as directed in the section "Stopping the Unit" in case the safety device fails to trip.
The high pressure switch must be manually rest; this is possible only when the pressure falls below the
set differential (see Table III).
MINIMUM PRESSURE SWITCH
The low pressure switch stops the compressor when the intake pressure falls below the set value for
more than 180 seconds.
The switch is automatically reset when the pressure rises above the set differential (see Table III);
however, the unit will not resume operation until the alarm memory on the microprocessor control is
cleared.
SERVICE THERMOSTAT
The function of this device is to start and stop the compressors according to the demand for chilled
water, as determined by a sensor placed at the evaporator inlet [water returning from the circuit]
This device is a function included in the microprocessor control and works with a proportional bandwidth
that may be set as desired.
ANTIFREEZE THERMOSTAT
The antifreeze sensor situated at the evaporator outlet detects the presence of excessively low
temperatures and stops the unit. Together with the flow switch and low pressure switch, this device
protects the evaporator from the risk of freezing as a result of faults in the water circuit.
This device is a function included in the microprocessor control.