24. OPERATION
CHARACTERISTICS
24.1. COOLING SET POINT
(Default defi ned) = 7°C, ∆t = 5°C.
24.2. HEATING SET POINT
(Default defi ned) = 45°C, ∆t = 5°C.
In case of restoring of the unit supplied
power after a momentary interrup-
tion, the pre-set mode is maintained in
memory.
24.3. COMPRESSOR START-UP
DELAY
To prevent the compressor start too
close to each other, two functions
have been arranged.
- Minimum time from last turnoff 60
seconds.
- Minimum time from last start 300 sec-
onds.
24.4. CIRCULATION PUMP
The electronic board provides an out-
put to manage the circulation pump.
After the fi rst 10 seconds of pump
operation, when the water fl ow rate is
running, activate the function of water
fl ow rate alarm (fl ow switch).
24.5. 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 heater
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 VERI-
FYING THAT IN THE WATER CIRCUIT IS AN
ANTIFREEZE SOLUTION.
The intervention of this alarm sets the
compressor block and not of the pump
block, which remains active, and the
heater starts up if installed.
For resetting the normal functions, the
water output temperature has to be
over +4 ° C, the reset is manual.
WARNING:
AT ANY INTERVENTIONS OF THIS ALARM
IT IS RECOMMENDED TO IMMEDIATELY
CONTACT THE NEAREST TECHNICAL
SERVICE ASSISTANCE
24.6. WATER FLOW RATE ALARM
The PGD1 provides the management
of a water fl ow rate alarm command-
ed from a fl ow switch installed on the
machine as standard. 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 com-
pressor and the pump.
WARNING
Inspection, maintenance
and possible repair opera-
tions must be carried out only
by an authorised technician
according to the law.
Unsuitable check/mainte-
nance operation may cause
damage to things and people.
25. 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:
25.6.1. 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 insula-
tion state
− Where provided the percentage of
glycol
25.6.2. Electric circuit
CONTROL:
− Efficiency of safety devices
− Electrical power supply
− Electrical power consumption
− Connections tightened
− Compressor casing heater
operation
25.6.3. Cooling circuit
CONTROL:
− Compressor conditions
− Efficiency of the tube core ex-
changer heater
− Working pressure
− Loss test for the control of the the
cooling circuit sealing
− High and low pressure switches
operation
− Perform the necessary checks on the
filter-drier to verify their efficiency.
25.6.4. Mechanical controls
CONTROL:
− The screws, compressors and the
electric box of the unit external pan-
elling 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.
26. EXTRAORDINARY
MAINTENANCE
The NXW 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. In the long run,
however, small leaks from the joints
may arise. Due to these leaks, the
refrigerant comes out and the circuit is
1 metro
1 metro
minimum technical spaces for maintenance
52
INXWPY. 1004. 4438805_00
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