25. FUNCTIONING
CHARACTERISTICS
25.1. COOLING SET POINT
(Default defi ned) = 7°C, ∆t = 5°C.
25.2. HEATING SET POINT
(Default defi ned) = 45°C, ∆t = 5°C.
In case of restoring of the unit supplied
power after a momentary interruption, the
pre-set mode is maintained in memory.
25.3. COMPRESSOR START DELAY
To prevent the compressor start too close
to each other, two functions have been
arranged.
− Minimum time from last turn-off
60 seconds.
− Minimum time from last start
300 seconds.
25.4. CIRCULATION PUMP
The electronic board provides an output to
manage the circulation pump.
After the fi rst 10 seconds of the pump
operation, when the water fl ow rate is
running, activate the function of water fl ow
rate alarm (fl ow switch).
25.5. ANTI-FREEZE ALARM
The anti-freeze alarm is active as if the
machine is turned-off or if the machine is in
standby mode. In order to prevent
breakage of the plate-type exchanger due
to freezing water contained, the compressor
is locked (if the machine is turned on under
4° C) and the resistance starts up (if standby
below 5° C).If the temperature detected by
the probe in the exchanger output and in
the chiller input is below +4 ° C.
WARNING
THE ANTI-FREEZE SET TEMPERATURE CAN
BE VARIED ONLY BY AN AUTHORISED
SERVICE CENTRE AND ONLY AFTER
VERIFYING THAT IN THE WATER CIRCUIT
IS AN ANTIFREEZE SOLUTION.
The intervention of this alarm sets the com-
pressor block and not of the pump, which
remains active, and the resistance starts-up
if installed.
For the restoration of the normal functions
of the temperature of the water output
have to come back over +4 ° C, the reset
is manual.
W
ARNING:
AT ANY INTERVENTIONS OF THIS
ALARM IT IS RECOMMENDED TO
IMMEDIATELY CONTACT THE NEAREST
TECHNICAL SERVICE ASSISTANCE
25.6. WATER FLOW RATE ALARM
The GR3 provides the management of a
water fl ow rate alarm commanded from a
fl ow switch standardly installed on the
machine. This safety type can occur after
the fi rst 10 seconds of operation of the
pump if the water fl ow rate is not suffi cient.
This alarm sets the block of the compressor
and the pump.
WARNING
Inspection, maintenance and
possible repair operations
must be carried out only by
an authorised technician
according to the law.
A deficient check/mainte-
nance operation may result
in damage to things and
people.
For machines installed near
the sea the maintenance
intervals must be halved.
26. REGULAR MAINTENANCE
Any cleaning operation is forbidden before
disconnecting the unit from the power
supply.
Check for voltage before operating.
Periodic maintenance is essential to maintain
the unit in perfect working order under the
functional as well as the energetic aspect.
Therefore it is essential to provide yearly
controls for the:
26.6.1. Hydraulic circuit
CONTROL:
− Water circuit filling
− Water filter cleaning
− Flow switch control
− Air in the circuit (leaks)
− That the water flow rate to the
evaporator is always constant
− The hydraulic piping thermal insulation
state
− Where provided the percentage of
glycol
26.6.2. Electric circuit
CONTROL:
− Efficiency of safety devices
− Electrical power supply
− Electrical power consumption
− Connections tightened
− Function of the compressor housing
resistance
26.6.3. Chiller circuit
CONTROL:
− Compressor conditions
− Efficiency of the plate-type exchanger
resistance
− Working pressure
− Loss test for the control of the sealing of
the refrigerant circuit
−
Function of high and low pressure switches
− Perform the necessary checks on the
filter-drier to verify their efficiency.
26.6.4. Mechanical controls
CONTROL:
− The screws, compressors and the
electric box of the unit external
panelling are properly tightened. If they
are poorly tightened, they produce
abnormal noise and vibrations
− The structure conditions.
If necessary, treat oxidised parts with
paints suitable for eliminating or
reducing oxidation.
27. EXTRAORDINARY
MAINTENANCE
The NRL are loaded with R410A gas and
tested in the factory. In normal conditions,
no Technical Assistance Service operation
is needed for the refrigerant gas check.
Along time, however, small leaks from the
joints may be generated. Due to these
leaks, the refrigerant comes out and
46
INRLPY. 02.10 4086916_01
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