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POWERCIAT LX ST/HE/XE
13.6.2 - Level 2
Clean the coil, using appropriate products. We recommend
cleaning with clear water to remove pollutants. If the use of
cleaning products is necessary, we specify:
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pH between 7 and 8
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Absence of chlorine, sulphate, copper, iron, nickel or
titanium
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Chemical compatibility with aluminium and copper.
For RTPF coils this process can either be carried out using a
high-pressure spray gun in the low-pressure position. With
pressurised cleaning methods care should be taken not to
damage the coil fins.
The spraying of the coil must be done:
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In the direction of the fins
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In the opposite direction of the air flow direction
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With a large diffuser (25-30°)
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At a minimum distance of 300 mm from the coil.
It is not necessary to rinse the coil, as the products used are pH
neutral. To ensure that the coil is perfectly clean, we recommend
rinsing with a low water flow rate.
For MCHE condenser coils refer to the instructions in chapter
12.6.1.2 under level 1 maintenance for use of a high-pressure
spray gun.
IMPORTANT:
• Never use pressurised water without a large diffuser. High
pressure cleaners are only permitted for MCHE coils
(maximum permitted pressure 6200 kPa (62 bar).
•
Concentrated and/or rotating water jets are strictly forbidden.
•
Never use a fluid with a temperature above 45 °C to clean
the air heat exchangers.
•
Correct and frequent cleaning (approximately every three
months) will prevent 2/3 of the corrosion problems.
•
Protect the control box during cleaning operations.
13.7 - Evaporator maintenance
Check that:
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The insulating foam is intact and securely in place.
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The cooler heaters are operating, secure and correctly
positioned.
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The water-side connections are clean and show no sign of
leakage.
13.8 - Compressor maintenance
13.8.1 - Oil separator
Check the correct operation of the heaters and check that they
are well attached to the oil separator ring.
13.8.2 -
Replacing the built-in oil filter
As system cleanliness is critical to reliable system operation, there
is a filter in the oil line at the oil separator outlet. The oil filter is
specified to provide a high level of filtration (5 µm) required for
long bearing life.
The filter should be checked after the first 500 hours of operation,
and every subsequent 2000 hours. The filter should be replaced
at any time when the pressure differential across the filter
exceeds 200 kPa (2 bar).
The pressure drop across the filter can be determined by
measuring the pressure at the filter service port and the oil
pressure port. The difference in these two pressures will be the
pressure drop across the filter, check valve, and solenoid valve.
The pressure drop across the check valve and solenoid valve is
approximately 40 kPa (0.4 bar), which should be subtracted from
the two oil pressure measurements to give the oil filter pressure
drop.
13.8.3 - Checking compressor rotation
Correct compressor rotation is one of the most critical application
considerations. Reverse rotation, even for a very short duration,
damages the compressor.
The reverse rotation protection scheme must be able to
determine the direction of rotation and stop the compressor within
300 ms. Reverse rotation is most likely to occur when-ever the
wiring to the compressor terminals is disturbed.
To minimize the opportunity for reverse rotation, the following
procedure must be applied. Rewire the power cables to the
compressor terminal pin as originally wired.
For replacement of the compressor, a low pressure switch is
included with the compressor. This low pressure switch should
be temporarily installed as a hard safety on the high pressure
part of the compressor. The purpose of this switch is to protect
the compressor against any wiring errors at the compressor
terminal pin. The electrical contact of the switch would be wired
in series with the high pressure switch. The switch will remain in
place until the compressor has been started and direction of
rotation has been verified; at this point, the switch will be
removed.
The pressure switch that has been selected for detecting reverse
rotation has the manufacturer part number HK01CB001. This
switch opens the contacts when the pressure falls below 7 kPa.
It is a switch with manual reset that can be reset after the pressure
rises back above 70 kPa. The pressure switch must be a manual
reset type to prevent any risk of the compressor short cycling in
the reverse direction.
13 - STANDARD MAINTENANCE
