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LCE

RG66004766_rev.05

9.2 MAXIMUM PRESSURE SWITCH

The high pressure switch is of the manually reset type and classifiable as category 4 in accordance with

the EEC 97/23 directive. It directly stops the compressor when the discharge pressure exceeds the set

value (see section 5.4).

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 is activated (i.e. the compressors stop) when the set value is reached.

Attention: during this operation, if the safety device fails to activate, the second cascade-

connected pressure switch will step in to shut down the unit. However, in any event you

should be ready to shut off the unit as directed in the section "Stopping the Unit" – see

also section 5.4.

The high pressure switch must be manually reset; this is possible only when the pressure falls below the

value indicated by set differential (see Table II).

9.3 MINIMUM PRESSURE SWITCH

The low pressure switch stops the compressor when the intake pressure falls below the set value for

more than 60 seconds.

The switch is automatically reset when the pressure rises above the value indicated by the set differential

(see Table II); however, the unit will not resume operation until the alarm memory on the microprocessor

control is cleared.

9.4 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 system].

This device is a function included in the microprocessor control and operates with proportional extension

band that can be set.

9.5 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.

9.6 ANTI-RECYCLE TIMER

The function of the timer is to prevent excessively frequent compressor starts and stops.

This device is a function included in the microprocessor control.

It sets a minimum time of 300 seconds between two consecutive starts.

Never modify the factory default delay value: wrong settings could cause serious

damage to the unit.

9.7 OIL DIFFERENTIAL PRESSURE SWITCH

LCE units are equipped with orbiting scroll compressors; these compressors do not have a lubricant

pump and therefore no oil differential pressure switch is provided.