11.8 - Frequency variator maintenance
ATTENTION: Before any intervention at the frequency variator,
ensure that the disconnect/isolator switch is open and that no
voltage is present (reminder: the capacitor discharge time is
approximately 20 minutes).
Only a well qualified person is allowed to replace or modify
the components inside the frequency variator.
During periodic inspections, check the ventilation grilles at the
frequency variator door; ensure that they are not pierced, damaged
or obstructed.
Replace the fan, if a “replace fan” alert/warning is displayed in the
alarm list.
For any other alarm or problem at the frequency variator, contact
the Carrier service department.
The frequency variators in the 30XW-V/30XWHV units do not
require a dielectric test, even if they are replaced parts: they are
systematically checked before delivery. Otherwise the filtering
components installed in the frequency variator can falsify the
measurement and may even be damaged.
If it is necessary to test the insulation of a component (e.g.
compressor, cables) the frequency variator must be disconnected
at the power circuit.
11.9 - Service valve (option 92)
The unit can be equipped with optional service valves to facilitate
maintenance and repair operations.
If option 92 is ordered, each refrigerant circuit will be supplied with
shut-off valves on the compressor economiser, discharge and
suction lines.
ATTENTION: The compressor suction valve must be used
without pressure difference at the terminals. If there is a
pressure difference, leak-tightness at the valve may be lost
and the valve can even fail altogether.
25
Equal pressure
11.10 - High pressure safety loop periodic test
The aim of this periodic test is to check the settings of the high
pressure safety loop on one of the unit’s refrigerant circuits and
check it is operating correctly. This procedure must be repeated
for each circuit.
Complete safety loop test
The purpose of this periodic test is to verify the proper functioning
and setting of the high-pressure safety loop of a refrigerant circuit.
In order to reach the triggering pressure of the loop, the pressure
and temperature thresholds activating the discharge of the
compressor by the regulation system are raised.
This procedure must be repeated for each circuit of the unit.
1. Set up a calibrated pressure gauge on the high pressure part
of the circuit (compressor discharge)
2. Reset all activated alarms
3. Activate the HP test mode for the corresponding circuit via the
control interface.
Enable Quick Test Mode (Quick Test Menu> [ QCK_TEST ]
parameter active)
Activate the high pressure test for the desired circuit (Menu Quick
Test> parameter [HP_TEST] to 0 for circuit A or 1 for the B circuit.
The corresponding circuit starts to perform the HP test.
4. Getting Started Machine
5. For water-cooled units, stop the circulation of the secondary
circuit to the condenser in order to stop the condensation and
cause the increase in pressure (this operation is managed by the
control on air-cooled machines)
6. Record the trigger value
7. Check that both HPS were triggered
If both HPS have tripped, go to step 10
If only one of the HPS has tripped, go to step 8
8. Replace the triggered HPS with another system whose trigger
value is adequate.
Alternatively, an emergency stop button can be installed.
9. Repeat steps 2 to 6
10. Check if the trigger values are correct
The release values should be between -1 .5 /+0.5 bars of nominal
values indicated on the unit.
11. Reset all alarms
12. Reset all HPS
Note:
Access to the maintenance functions can be protected by a
password. Contact your dealer or the manufacturer’s service
department for more information.
For step 8, the electrical disconnection of the triggered HPS
and its substitution must be performed in an environment
with live parts. All the procedures and authorization provided
for this type of intervention must be respected.
The type of connector must be WAGO 231-302 or equivalent.
11 - STANDARD MAINTENANCE
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