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RG66007169 - Rev 00
7
CONTROL AND SAFETY DEVICES
All the control and safety devices are set and tested in the factory before the unit is dispatched.
7.1 CONTROL
DEVICES
7.1.1 SERVICE
THERMOSTAT
The service thermostat activates and deactivates the compressor according to the demand for chilled water (cooling mode) or heated water (heat pump
mode), as determined by a sensor installed on the water exchanger inlet. This device is governed by the microprocessor control (see also the chapter
regarding the microprocessor).
7.1.2
CONTROL DEVICE SETTINGS
Control devices
Set point min max differenzial
Service thermostat
°C
11,5
8
20
2
(outlet water temp. cooling mode)
Service thermostat
°C
45
25
47
3
(outlet water temp. heat pump mode)
7.2 SAFETY
DEVICES
7.2.1
HIGH PRESSURE SWITCH
The high pressure switch stops the compressor when the delivery pressure exceeds the set value.
7.2.2
REFRIGERANT CIRCUIT SAFETY VALVE (NOT AVAILABLE FOR MPE 09-15)
The safety valve is triggered in the event of a malfunctioning of the high pressure switch or in case of fire.
Warning
The safety valve is situated in the compressor compartment inside the unit. Never attempt to access internal components of the unit
until you have disconnected the power supply.
7.2.3
LOW PRESSURE SWITCH
The low pressure switch stops the compressor when the intake pressure falls below the set value.
7.2.4 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 prevents the compressor from starting up again after a stop until a set period of time has elapsed (approximately 5 minutes).
7.2.5
ANTIFREEZE THERMOSTAT
The antifreeze thermostat situated at the evaporator outlet performs a dual function: it prevents ice from forming in the evaporator in the event of an
excessive decrease in the water flow; it stops the unit in the event of a failure of the service thermostat.
This device is governed by the microprocessor control (see also the chapter regarding the microprocessor).
7.2.6
WATER DIFFERENTIAL PRESSURE SWITCH
The water differential pressure switch stops the unit in the event of an excessive reduction in the water flow, thus protecting it from the formation of ice
(chiller operation) and excessively high condensation temperatures (heat pump operation)
7.2.7
WATER SAFETY VALVE
The water safety valve opens when the pressure within the water circuit reaches a level that may cause damage to the unit.
7.2.8
SAFETY DEVICE SETTINGS
Safety device
activation
differential
resetting
Maximum pressure switch (bars)
42
Automatic
Refrigerant safety valve (bars)
45
Minimum pressure switch (bars)
2
Automatic
Antifreeze thermostat (°C)
3
3
Manual
Water differential pressure switch (bars) 0,050
0
Automatic
Water safety valve (bars)
4
