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If compressors or compressor oils need to be removed, make sure they have been evacuated to an acceptable level
to ensure that flammable refrigerant does not remain within the lubricant. The evacuation process must be carried out
before returning the compressor to suppliers. To speed up this process, only electrical heating of the compressor body
must be used. When oil is drained from a system, it must be done safely.
Work procedure.
The work must be carried out according to a controlled procedure in order to minimize the risk of the presence of
flammable gas or vapor during the execution of the work.
1. General work area: all maintenance personnel and others working in the local area should be educated on the
nature of the work being performed. Work in confined spaces must be avoided. The area around the work area
must be sectioned. Ensure that conditions within the area have been secured by the control of flammable material.
2. No ignition sources: No person carrying out work in relation to a refrigeration system involving exposure to piping
must use sources of ignition in a way that creates the risk of fire or explosion. All possible sources of ignition,
including cigarette smoke, must be kept sufficiently far from the place of installation, repair, removal and disposal,
during which the refrigerant may possibly be released into the surrounding space. Before starting work, the area
around the equipment must be checked to ensure that there is no risk of flammability or ignition hazards. "No
smoking" signs must be displayed.
Removal and evacuation.
When breaking into the refrigerant circuit to make repairs or for any other purpose, conventional procedures must be
used. However, for flammable refrigerants it is important to follow the best procedures as there is a risk of flammability.
The following procedure must be followed:
•
remove the refrigerant;
•
purge the circuit with inert gas; evacuate;
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purge again with inert gas;
•
open the circuit by cutting or brazing.
The refrigerant charge must be recovered in the correct recovery cylinders. For appliances containing flammable
refrigerants, the system must be flushed with OFN to make the unit safe. You may need to repeat this process
several times. Compressed air or oxygen must not be used for purging refrigerant systems. For appliances containing
flammable refrigerants, flushing must be achieved by breaking the vacuum in the system with OFN and continuing to
fill until the operating pressure is reached, then discharging to the atmosphere and finally lowering the vacuum. This
process must be repeated until there is no more refrigerant in the system. When the final OFN charge is used, the
system must be vented to atmospheric pressure to allow the work to be carried out. This operation is absolutely essential
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..
Charging procedures.
In addition to conventional charging procedures, the following requirements must be followed:
•
Make sure that contamination of different refrigerants does not occur when using charging equipment. Hoses or
lines should be as short as possible to minimize the amount of refrigerant they contain.
•
The cylinders must be kept upright.
•
Make sure the refrigeration system is grounded before charging the system with refrigerant.
•
Label the system when charging is complete (if not already done).
•
Be very careful not to overfill the refrigeration system.
Before recharging the system, it must be pressure tested with the appropriate purge gas. The system must undergo a
leak test upon completion of the charge but prior to commissioning. A subsequent leak test
must be carried out before leaving the site.
V 11/23
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