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1.3 - Maintenance safety considerations
Engineers working on the electric or refrigeration compo-
nents must be authorized, trained and fully qualified to do so.
All refrigerant circuit repairs must be carried out by a trained
person, fully qualified to work on these units. He must have
been trained and be familiar with the equipment and the
installation. All welding operations must be carried out by
qualified specialists.
Any manipulation (opening or closing) of a shut-off
valve must be carried out by a qualified and authorised
engineer. These procedures must be carried out with the
unit shut-down.
NOTE: The unit must never be left shut down with the
liquid line valve closed, as liquid refrigerant can be trapped
between this valve and the expansion device. (This valve
is situated on the liquid line before the filter drier box.)
During any handling, maintenance and service operations
the engineers working on the unit must be equipped with
safety gloves, glasses, shoes and protective clothing.
Never work on a unit that is still energized.
Never work on any of the electrical components, until the
general power supply to the unit has been cut using the
disconnect switch(es) in the control box(es).
If any maintenance operations are carried out on the unit,
lock the power supply circuit in the open position ahead
of the machine.
If the work is interrupted, always ensure that all circuits
are still deenergized before resuming the work.
ATTENTION: Even if the unit has been switched off, the
power circuit remains energized, unless the unit or circuit
disconnect switch is open. Refer to the wiring diagram for
further details. Attach appropriate safety labels.
Operating checks: During the life-time of the system,
inspection and tests must be carried out in accordance
with national regulations.
The information on operating inspections given in annex
C of standard EN278-2 can be used if no similar criteria
exist in the national regulations.
While working in the fan area, especially when grilles or
casings are removed, disconnect the fan power supply to
prevent their automatic restart.
Safety device checks (annex C6 – EN378-2): The safety
devices must be checked on site once a year for safety
devices (high-pressure switches), and every five years for
external overpressure devices (pressure relief valves).
Check manual “30XA Pro-Dialog Control” for a detailed
explanation of the high-pressure switch test method.
At least once a year thoroughly inspect the protection
devices (valves). If the machine operates in a corrosive
environment, inspect the protection devices more frequently.
Regularly carry out leak tests and immediately repair
any leaks.
Ensure regularly that the vibration levels remain accep-
table and close to those at the initial unit start-up.
Before opening a refrigerant circuit, purge and consult the
pressure gauges.
Change the refrigerant when there are equipment failures,
following a procedure such as the one described in NFE
29-795 or carry out a refrigerant analysis in a specialist
laboratory.
Plug all openings whenever the refrigerant circuit is opened
for up to one day. For longer openings place a nitrogen
charge in the circuit.
1.4 - Repair safety considerations
All installation parts must be maintained by the personnel in
charge, in order to avoid material deterioration and injuries
to people. Faults and leaks must be repaired immediately.
The authorized technician must have the responsibility to
repair the fault immediately. Each time repairs have been
carried out to the unit, the operation of the safety devices
must be re-checked.
Comply with the regulations and recommendations in unit
and HVAC installation safety standards, such as: EN 378,
ISO 5149, etc.
If a leak occurs or if the refrigerant becomes contaminated
(e.g. by a short circuit in a motor) remove the complete
charge using a recovery unit and store the refrigerant in
mobile containers.
Repair the leak detected and recharge the circuit with the
total R134a charge, as indicated on the unit name plate.
Certain parts of the circuit can be isolated. Only charge
liquid refrigerant R134a at the liquid line.
Ensure that you are using the correct refrigerant type
before recharging the unit.
Charging any refrigerant other than the original charge
type (R134a) will impair machine operation and can even
lead to a destruction of the compressors. The compressors
operating with this refrigerant type are lubricated with a
synthetic polyolester oil.
Do not use oxygen to purge lines or to pressurize a machine
for any purpose. Oxygen gas reacts violently with oil,
grease, and other common substances.
Never exceed the specified maximum operating pressures.
Verify the allowable maximum high- and low-side test
pressures by checking the instructions in this manual and
the pressures given on the unit name plate.
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