Flooded type water cooled screw chiller (PCB Control)
97
5)
The unit must be disconnected from the power supply during inspection or replacement of the lines
of the unit.
If it is required to tighten the line bank screw or replacing the wire and element in the electrical
cabinet during commissioning and maintenance, it shall be down when the power supply is
disconnected. Similar operations by the user in later maintenance and service shall also be done
when the power supply is disconnected.
6)
The non-user parameters in the touch screen of the unit and electronic expansion valve control
module are forbidden to be changed.
The non-user parameters in the touch screen of the unit and electronic expansion valve control
module are directly related to the performance and reliability of the unit, and are not allowed to be
changed in principle. Even if it is required to adjust some parameters due to special local climate, it
shall be done by or under the instructions of after-sale personnel or professionals in the factory.
7)
If any exceptional case occurs to the unit, it is forbidden to forcibly start up the unit unless under the
instructions of professionals.
Exceptional temperature, pressure, sound, or vibration, etc. of the unit during the running shall be
clearly recorded in details, and reported to after-sale personnel or professionals in the factory. It is
forbidden to forcibly start up the unit unless permitted.
2.
Maintenace
If the problem is much more serious, contact your local Midea or your local representative for assistance.
Cleaning Heat Exchangers
Check the chiller tightness and whether
there’s leak of heat exchange tubes. It is necessary to do
nondestructive inspection for the principal weld (longitudinal and circumferential weld of
evaporator/condenser barrel) of pressure vessel. Inspect and clean cooler tubes at the end of the first
operating season. Tube condition in the exchanger will determine the scheduled frequency for cleaning,
and will indicate whether water treatment is adequate in the water circuit. Too much scale will cause big
loss of capacity and efficiency.
Refer to the following pressure-temperature curve for condition in heat exchangers:
High pressure-cooling water temperature (high pressure beyond 0.6~1.2MPa is abnormal)
Fig.26 High pressure at full load (standard unit)
