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21 - GENERAL MAINTENANCE
ATTENTION: Before starting any servicing or maintenance
operation on the unit, make sure that the power supply has been
disconnected. A current discharge could cause personal injury.
In order to obtain maximum performance from the unit
special attention should be paid to the following points:
- Electrical connections: The supply voltage should be
±10% of the nominal voltage limits.
Ensure that no faulty contacts exist in the terminal blocks,
contactor boards, etc. Make sure that all the electrical
connections are properly tightened, and that all the
electrical components (contactors, relays, etc.) are firmly
secured to the corresponding rails.
Pay special attention to the condition of the connecting
cables between the control elements and the electrical box,
and to that of the unit power supply cable. They should
not be twisted and there should be no slits or notches in
the insulation. Check the starting and running
consumptions are within the limits specified in the
corresponding technical information.
- Refrigerant circuit: Ensure that there is no leakage of
refrigerant or oil from the compressor. Check that the high
and low side operating pressures are normal. Make sure
that the coils are not dirty. If necessary an optional filter
may be placed at the outdoor air inlet. Check for unusual
compressor noise.
- Controls: Check the operation of all electric controls,
high and low pressure stats, etc.
The minimal maintenance operations and their periodicity
will be made according to the national regulations.
All work on the unit's electrical or refrigerant systems must
be carried out by a qualified authorized technician. See the
standard EN 378-4.
It is advisable to sign a maintenance contract with the install-
er or an approved maintenance company.
21.1 - General recommendations:
21.1.1 - Safety instructions
- Technicians working on the unit must wear the necessary
safety gear (e.g. gloves, eye protection, insulating clothing,
safety shoes).
- Similarly, it is recommended that personnel working close
to sources of high noise emission wear ear defenders.
The ear defenders should in no way impede the wearing of
other protective equipment.
- The surfaces of the compressor and pipes may reach
temperatures of over 100°C and cause burns if touched.
Likewise, the surfaces of the compressor may in some cases
drop to freezing temperatures which can cause frostbite. It is
therefore important to take special care when carrying out
maintenance work.
- Do not climb on the machine; use a platform to work at the
necessary height.
- Do not climb on the copper refrigerant pipes.
Caution: Do not work on any electrical components
without first turning off the main door switch in
the electric panel.
21.1.2 - Preliminary advice
Keep the unit clean.
- Keep the space surrounding the unit clean and cleared in
order to avoid accidents and ensure the proper ventilation
of the coil.
- Perform a visual (remains of water or oil below or around
the unit) and auditory inspection of the entire installation.
- In general, a corrosion control must be performed on the
metallic parts of the unit (frame, bodywork, exchangers,
electric panel, etc.).
- Check that the insulation foam is not unstuck or torn.
- All the electric connection states must be checked as well, as
well as the air tightness of the different circuits.
- Check whether the safety devices and the expansion valve(s)
operate correctly.
- Check all the values listed in the table "Operating readings"
on chapter 11.
21.2 - Access to main elements
21.2.1 - Air coil
- Check that the coil is free from dust and grease.
- Cleaning the accumulated dust on the coil can be performed
with a vacuum cleaner perpendicular to the fi ns or with a
low pressure water cleaner. Grease can be removed with
water with degreaser. Do not put stress on the fins as they
could deform.
Use safety gloves for this task. Take care with the
sharp parts of the coil.
21.2.2 - Condensate drain pan
- Check that the condensate pan is clean. There should be no
stagnant water.
- Check that the drain is not clogged.
- Cleaning of the pan can be done with water and
non-abrasive detergent.
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