53
ATTENTION
When you have to take measurements with the machine
on and the electrical panel and refrigeration circuit
open, you must pay attention that the machine is under
voltage, the refrigeration circuit contains high pressure
gas, the pipes can be hot or cold, some parts can be in
motion.
ATTENTION
Do not use compressed air or oxygen for these
operations.
• Personnel approaching the machine must be competent in
the use of this refrigerant and comply with current regulations.
Evaluate procedures prescribed by Aermec and fire regulations
to avoid inconsistencies between our prescriptions and the
regulations in force.
• Any extraordinary maintenance or repairs on the unit must be
carried out by specialized technicians or qualified personnel.
• Before carrying out this procedure, it is essential that the tech
-
nician is fully familiar with the equipment and all its details.
• Make sure that all PPE (personal protective equipment) comply
with the regulations in force.
• Make sure that all the devices used to remove the refrigerant
comply with the regulations in force.
• Before the emptying operation, it is necessary to take and ana
-
lyze a sample of refrigerant and oil. Ensure the required power
before testing.
• Make sure that the power supply is switched on and that the
unit is powered up before proceeding with the operations.
EXECUTION OF THE VACUUM
Removal and evacuation
• The intervention must be carried out by specialized techni-
cians or qualified personnel.
• Turn off the unit and disconnect the power supply.
• Drain the refrigerant following the appropriate procedure; the
gas should be disposed of in a suitable torch with an anti-back
-
fire device.
• Make sure that there is no naked flames near the suction pump
outlet, and that it is well ventilated.
The following procedure must be followed:
• remove the coolant,
• purge the circuit with inert gas,
• evacuate,
• purge again with inert gas,
• open the circuit by cutting or brazing.
The refrigerant must be recovered in the appropriate tanks.
The system must be "flushed" with OFN (Oxygen Free Nitrogen)
to make the unit safe. You may need to repeat this process several
times.
Before carrying out the procedure make sure that:
• adequate mechanical handling equipment is available to be
used, where necessary, for handling the refrigerant cylinders,
• PPE (personal protective equipment) are available and are
used correctly,
• the refrigerant recovery process is supervised at all times by a
qualified and competent person,
• recovery equipment and cylinders that meet the appropriate
standards.
PROCEDURE TO FOLLOW FOR THE EXECUTION OF THE
VACUUM
• Disconnect the power supply.
• Make sure that all PPE (personal protective equipment) comply
with the regulations in force.
• Make sure that all the devices used to remove the refrigerant
comply with the regulations in force.
• Draw the refrigerant from the circuit. If it is not possible to suck
from a single point, use other sockets to unload the system.
• Before performing these procedures, make sure the holding
tank is large enough.
• Fill the tank up to and not more than 80% of its capacity.
• Do not exceed the maximum pressure allowed by the tank
even if the working times are short.
• Once the discharge is complete, quickly close the valves and
remove the equipment used.
• Make sure that the refrigerant has been cleaned before using
it on other systems.
• The identification of the recovered refrigerant must be carried
out after the unit has been unloaded. The identification of the
refrigerant must contain the date and approval. Make sure that
the signs regarding the flammable refrigerant contained are
shown on the unit.
Flushing must be achieved by breaking the vacuum in the system
with OFN (Oxygen Free Nitrogen) and continuing to fill until the
operating pressure is reached, then discharging to the atmos
-
phere and finally lowering to the vacuum. This process must be
repeated until there is no refrigerant in the system. When the
OFN final charge is used, the system must be discharged to at
-
mospheric pressure to allow the work to take place. This opera-
tion is absolutely vital if you want to carry out brazing operations
on the pipes.
Make sure that the vacuum pump outlet is not close to ignition
sources and that ventilation is available.
• When the cylinders have been filled correctly and the process
completed, ensure that the cylinders and equipment are
promptly removed from the site and that all isolation valves
are closed.
• The recovered refrigerant must not be charged to another
refrigeration system unless it has been cleaned and checked.
(see recycling procedure)
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