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18 - SERVICING AND MAINTENANCE
18.2.4 - Refrigerants - general information
- Always remember that refrigeration systems contain
pressurised liquids and vapours.
- All necessary measures must be taken when partially opening
the system: Make sure that there is no pressure in the part
of the circuit concerned.
- Partial opening of the primary refrigerant circuit will cause a
certain quantity of refrigerant to be released into the
atmosphere.
- It is essential to keep the amount of lost refrigerant as low
as possible by pumping the charge and isolating it in another
part of the system.
- The refrigerant and lubricating oil, and the low-temperature
liquid refrigerant in particular, may cause inflammatory lesions
similar to burns if they come into contact with the skin or eyes.
Always wear protective eyewear, gloves and other protective
equipment when opening pipes or tanks liable to have liquids in
them. Store unused refrigerant in the appropriate containers and
limit the amounts stored in mechanical rooms.
- Cylinders and tanks of refrigerant must be handled with care
and signs warning users of the related poisoning, fire and
explosion hazards must be clearly visible. Refrigerant that
reaches the end of its life must be collected and recycled in
accordance with applicable regulations.
18.2.5 - Halocarbon and hydrofluorocarbon
refrigerants
Although non-toxic, vapours from halocarbon and hydrofluorocarbon
refrigerants are still hazardous because they are heavier than air
and can force the latter out of the machine rooms.
If refrigerant is accidentally released, ventilate the room with fans.
Exposure levels in workplaces must be kept to a practical minimum
and must never exceed the recognised limit of 1000 ppm for an
8-hour working day and a 40-hour working week.
Although halocarbon and hydrofluorocarbon refrigerants are not
flammable, keep them away from open flames (e.g. cigarettes,
etc.), as temperatures of over 300°C cause their vapours to break
down and form phosgene, hydrogen fluoride, hydrogen chloride
and other toxic compounds. These compounds may produce
severe physiological consequences if accidentally inhaled or
swallowed.
Warning : Do not expose vapours and zeotropic blends of
refrigerants containing R32 to open flames (such as cigarettes).
Refrigerants must be evacuated from pipes and tanks before
commencing any cutting or welding work. Do not use a torch to
check for leaks of refrigerants containing halocarbons such as
R410A, and its by-products.
NOTE : AQUASNAP 30WI machines operate using R410A. It is
essential that technicians use equipment which is compatible with
R410A with a working pressure which is approximately 1.5 times
higher than that of units using R407C.
18.2.6 - Servicing
- Note down the operating readings and perform the checks
indicated in the table on the previous page at least twice a
year and each time a unit is started up.
22
■ Weekly checks
With the unit running at full capacity, check the following values:
- Check the entire system for traces of water/oil under or
around the unit and for any unusual noises.
- LP compressor suction pressure,
- HP compressor discharge pressure,
- The water inlet and outlet temperatures in the exchangers
- The charge via the liquid sight glass and the condition of the
charge using the coloured indicator on the sight glass
- The oil level and its appearance. If the colour changes, check
the quality.
- Keep the unit clean.
■ Monthly checks
- Check all the values listed in the "Operating readings" table
on the previous page.
- Perform a corrosion check on all the metal parts. (Frame,
casing, exchangers, electrical boxes etc.)
- Make sure that the insulating foam is not detached or torn.
- Check the energy transfer fluids for any impurities which
could cause wear or corrosion in the exchanger.
- Check the circuits for leaks.
- Check whether the safety devices and the expansion valve(s)
operate correctly every 6 months.
■ Annual checks
- Carry out the same inspections as during the monthly checks.
- Test the oil for contaminants: if acid, water or metal particles
are detected in the oil, replace it in the corresponding circuit
and the dryer.
- If the whole oil load is being changed, use only new oil of the
same grade as the original oil, which has been stored in a
hermetically sealed container until loading. Oil type: (see
section 11 Main components of the refrigerating circuit).
- Check the filter dryer for clogging (measure the difference in
the temperature of the pipes at the dryer inlet and outlet).
- Clean the water filter and vent air from the circuit.
- Clean the exchangers and check the pressure drop in each.
- Check the operation of the water flow switch.
- Check the water quality or condition of the coolant.
- Check the antifreeze concentration (MEG or PEG)
- Disconnect all the cables and check the insulation of the
motor and the resistance of the windings.
- Check the electrical connections to ensure they are tight and
in good condition.
- Check the condition of the contacts and the current at full
load on all three phases
- Check the electrical box for water seepage.
NB : The cleaning intervals are given as a guide and should be
adapted to each installation.
18.2.7 - Disassembling the compressor
The compressor is fastened to the platform by four dia. 8 mm
screws.
Caution : If you do not have a torque wrench when tightening
these screws, you should only tighten them until they are snug
and then tighten a further ¾ turn.
IMPORTANT :
To ensure your unit runs smoothly and to obtain service under
the warranty, take out a maintenance contract with your
installer or an approved maintenance company.
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