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C6.2.38/0719/E
6.2 Preparation and work procedure
A work procedure shall be provided in the preparation stage. All maintenance staff and others
working at the site shall be instructed on the nature of the work being carried out.
If any work is to be conducted on the refrigeration systems or any associated parts, appropriate fire
extinguishing equipment shall be provided. Dry powder or CO
2
fire extinguishers are considered
appropriate. Confirm that appropriate fire extinguishing equipment is available near the work area.
Work shall be undertaken under a controlled procedure so as to minimize the risk of a flammable
gas or vapour being present while the work is being performed.
Prior to starting to work on systems containing flammable refrigerants, safety checks are necessary
to ensure that the risk of ignition is minimized.
Avoid working on systems filled with flammable refrigerant in a confined space.
6.3 Disassembling system components
When disassembling system components please follow the main steps described hereunder:
1.
Recover refrigerant and evacuate system using an A3-dedicated recovery unit and vacuum
pump. All refrigerants shall be recovered to avoid significant release. Ensure that the outlet of
the vacuum pump is not close to any potential ignition source and that ventilation is available.
2.
Flush system with dry nitrogen. Compressed air or oxygen shall not be used for purging
refrigerant systems.
3.
Disassemble components with a cutting tool.
4.
Drain, recover and dispose of compressor oil as appropriate.
To disconnect:
▪
Using a pipe cutting tool, cut off the suction and discharge
lines in such a manner that the new compressor can easily be
re-connected into the system.
▪
Heat joint areas 2 and 3 slowly and uniformly until the braze
material softens and the tube end can be pulled out of the
fitting.
To reconnect:
▪
Recommended brazing material: Silfos with minimum 5% silver or silver braze used on other
compressors.
▪
Due to the different thermal properties of steel and copper, brazing procedures may have to be
changed from those commonly used.
NOTE: Since the discharge stub contains a check valve, care must be taken not to overheat
it to prevent brazing material from flowing into it.
6.4 Provisions of legislation and leak check requirements
According to EN 378-4, systems with a refrigerant charge above 3 kg shall be subject to tightness
inspection at least on an annual basis. The owner/operator shall keep an updated logbook of the
refrigerant system containing all details with regard to maintenance and repair works (quantities and
type of refrigerant changed or transferred, system components changes and replacements, etc.).
The F-gas Regulation (EU) No 517/2014 contains additional requirements depending on the system
and stipulates training requirements for alternative refrigerants.
6.5 Exchanging the refrigerant
WARNING
Air/R290 mixture! Flammable atmosphere! Explosion hazard!
In any case
avoid air/R290 mixture in the refrigeration system. Make sure that the system
is filled with pure R290 refrigerant. In the event that the refrigerant needs
replacing, the charge should be recovered using R290 qualified refrigerant
recovery unit and recycling bottles.
Figure 20: Tube connecting areas