18
AGL_Unit_ZX_Small_E_Rev03
5
Maintenance & repair
5.1 Replacing a compressor
CAUTION
Inadequate lubrication! Bearing destruction!
If the system contains one,
exchange the accumulator after replacing a compressor with a burned-out
motor. The accumulator oil return orifice or screen may be plugged with
debris or may become plugged. This will result in starvation of oil to the new
compressor and a second failure.
In the case of a motor burnout, the majority of contaminated oil will be removed with the
compressor. The rest of the oil is cleaned through the use of suction and liquid line filter driers. A
100 % activated alumina suction line filter drier is recommended but must be removed after
72 hours.
It is highly recommended to replace the suction accumulator, if the system
contains one.
This is because the accumulator oil return orifice or screen may be plugged with
debris or may become plugged shortly after a compressor failure. This will result in starvation of oil
to the replacement compressor and a second failure. When a compressor is exchanged in the field,
it is possible that a major portion of the oil may still be in the system. While this may not affect the
reliability of the replacement compressor, the extra oil will add to rotor drag and increase power
usage.
▪
De-energize the refrigeration unit before any intervention.
▪
Close valves to isolate the unit from the system.
▪
Recover the refrigerant from the unit and make sure that the compressor is not under pressure.
▪
Release the compressor mounting parts then lift the compressor and replace it with the new
one.
NOTE: For more information about unit components and spare parts, please refer to the
compressor application guidelines and to the Copeland Spare Parts Catalogue available at
www.climate.emerson.com/en-gb/tools-resources
5.2 Safety devices
During regular maintenance, all mechanical safety devices such as high- and low-pressure
switches must be checked for proper functioning and triggering at adjusted setpoints.
In case of high- and/or low-pressure switch replacement, the triggering points must be checked
before putting the system back in operation.
5.3 Condenser fins
WARNING
Uncovered rotating parts! Personal injuries!
Exercise great caution
during maintenance when the housing is removed: the fan can start
unexpectedly and cause personal injuries or damage to the maintenance
tools.
CAUTION
Acid cleaning! Corrosion of condenser fins!
Do not use acidic solutions
to clean the coil. After cleaning, the fins should be brushed lightly with a
proper fin comb.
Condenser fins become dirty over time as ambient air is induced to the condenser. Dirty coil
surfaces result in high condensing temperatures and poor unit performance. Regular cleaning is
recommended, the frequency of doing so being dependent on the installation and the surrounding
environment. As a general guide it is advisable to do this at least once every 6 months.
As a general rule and for a clean environment we recommend that the fins be cleaned with liquid
detergent diluted with clean water. The ZX Small unit has a well-designed chassis with falling levels
towards a large drainage hole and provided the unit is installed level, any cleaning solution should
be able to drain away. A light brush downward (in the direction of the fins) should be done before
washing to remove heavy deposits.
