• 32 • Installation - Operation - Maintenance manual (IOM) • AIR COOLED CHILLERS & SPLIT UNITS - 0105-E
3) Clean any corroded surfaces and repaint them.
4) Inspect the chilled water circuit for any signs of leakage.
Check operation of the water circulating pump and its ancillaries.
Check the percentage of antifreeze in the chilled water circuit, top up as necessary (if antifreeze is used).
5) Carry out all weekly maintenance duties.
The first and last inspection will include the seasonal shutdown procedure or the restarting procedure depending
on the case.
These inspections should include the following operations:
- Check the contacts of motor contactors and control devices.
- Check the adjustment and operation of each control device.
- Conduct an oil analysis to determine the acidity. Record the results.
- Chanage the oil if necessary.
WARNING : Oil analyses should be carried out by a qualified technician. Misinterpretation of the results could cause
damage to the equipment.
Also, analysis operations should be conducted according to the right procedures, so as to avoid accidents and
potential injury of service personnel.
- Follow the recommendations given by LENNOX as concerns compressor oil (see the appropriate table).
- Conduct a refrigerant leak test.
- Check motor winding isolation.
Other operations may be necessary depending on the age and the number of hours of operation of the installation.
7.3 CLEANING THE CONDENSER
7.3.1 Air cooled condensers
Clean the coils either with a vacuum cleaner, cold water, compressed air, or with a soft brush (non metallic). On
units installed in a corrosive atmosphere, coil cleaning should be part of the regular maintenance program.
On this type of installation, all dust gathered on the coils should be quickly removed by regular cleaning.
Caution: do not use high pressure cleaners that could cause permanent damage to the aluminium coil fins.
7.3.2 Multitube water cooled condensers
Use a cylindrical brush to remove sludge and other substances in suspension inside the condenser tubes. Use a
non corrosive solvent to remove scale deposits.
The water circuit in the condenser is manufactured in steel and copper. A water treatment specialist, given the right
information, will be able to recommend the right solvent for removing scale.
The equipment to be used for external water circulation, the quantity of solvent and the safety measures to be taken
must be approved by the company supplying the cleaning products or by the company conducting these operations.
7.4 COMPRESSORS / OIL DRAINAGE
Oil for refrigeration equipment is clear and transparent. It keeps its colour over a long period of operation.
Given that a correctly designed and installed refrigeration system will operate without any problems, there is no
need to replace the compressor oil even after a very long period of operation.
Oil that has become dark in colour has been exposed to impurities in the refrigeration piping system or to excessive
temperatures on the discharge side of the compressor, and this inevitably impairs the quality of the oil. Darkening
of the colour of the oil or degradation of its qualities can also be caused by the presence of humidity in the system.
When the oil has changed colour or has been degraded, it must be changed.
In this event, before putting the unit back into service, the compressor and the refrigeration circuit will have to be
evacuated.
7.5 IMPORTANT
Before proceeding with any service operations, make sure that the power supply to the unit is switched off.
When the refrigeration circuit has been opened it will have to be evacuated, recharged, and inspected to ensure
that it is perfectly clean (filter-drier) and leaktight. Remember that only trained and qualified personnel are
authorised to open a refrigeration circuit.
Regulations stipulate recovery of refrigerants and forbid willful discharge of refrigerants into the atmosphere.
MAINTENANCE
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