52
11.3.3 - Restart after high pressure detection
After detecting the overpressure, it is necessary to manually reset
the switched HPS (s). Using a dull tool with a diameter of less than
6 mm if the PZHH HPS is deactivated.
11.3.4 - Checks in case of apparent failure of the
safety accessory
If the operating pressure of the unit appears to have been exceeded
(for example: after opening of the relief valves), the unit must be
stopped immediately. The unit and the safety loop must pass all
periodic checks before any possible restart.
If the test reveals any malfunctions that could have led to exceed
the maximum allowable pressure (PS) of the device, a complete
check of all pressure equipment must be performed to verify their
mechanical integrity.
11.3.5 - High pressure safety loop periodic test
In order to verify the full integrity of the safety loop, the following
checks have to be performed periodically:
-
Contactors check
-
Complete loop operation check
11.3.5.1 -
Power contactor check procedure
This procedure shall be applied for each compressor of the unit.
1. Switch off the power of the electrical equipment.
Apply all safety procedures for access to equipment with
hazardous voltage.
2. Measure the resistance between upstream and downstream
terminals of the main power contactors KM- and KM-D for each
phase.
Note: calibrated Ohmmeter shall be used for this task.
3- Confirm resistance is more than 1.0 MOhm.
A resistance lower than 1.0 MOhm, indicates that contactor KM_
or KM_D is defective: further investigations and replacement of the
failed part is required.
Downstream terminals of KM- and KM-D contactors
Upstream terminals of KM- and KM-D contactors
11.3.5.2 - 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. C heck 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 triggeredg 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 -1.4 / +0 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.
11.4 - Condensers
30XB(E/P)ZE coils are all-aluminium micro-channel condensers.
11.5 - Fans
The fans are axial Flying Bird fans equipped with rotating shroud
and made of composite recyclable material. Each motor is fixed
with transverse supports. The motors are three-phase, with
permanently lubricated bearings and insulation class F (level IP55).
11 -MAJOR SYSTEM COMPONENTS AND OPERATION DATA
