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15 - MAINTENANCE PROGRAM
All maintenance operations must be carried out by technicians
who have been trained on Danfoss products, observing all
Danfoss quality and safety standards.
15.1 - Maintenance schedule
Regular maintenance is indispensable to optimise equip-ment
operating life and reliability. Maintenance operations must be
carried out in accordance with the schedules below:
Service
Frequency
A
Weekly
B
Monthly
C
Annually
D
Special cases
If the equipment does not operate normally during main-
tenance operations, refer to the chapter on diagnostics and
breakdowns of the BW10 Control manual).
IMPORTANT: Before each equipment maintenance
operation please ensure that:
•
the unit is in the OFF position
•
it is impossible for the unit to restart automatically
during maintenance.
15.2 - Description of the maintenance operations
The equipment is supplied with polyolester oil (POE). Use only
Danfoss-approved oil.
Service A
Full-load operating test
Verify the following values:
•
compressor high-pressure side discharge pressure
•
compressor low-pressure side suction pressure
•
charge visible in the sight glass
•
temperature difference between the heat exchanger water
entering and leaving temperature.
Verify the alarm status
Service B
Carry out the operations listed under Service A.
Refrigerant circuit
•
Full-load operating test. In addition to the operations
described under Service A, check the following values:
-
compressor discharge pressure
-
compressor oil level
-
actual liquid subcooling
-
overheating at the expansion device
•
Verify the charge status by checking the colour indicator
of the sight glass. If the colour has turned to yellow,
change the charge and replace the filter drier cartridges
after carrying out a leak test of the circuit.
Electrical checks
•
Check the tightening of the electric connections,
contactors, disconnect switch and transformer.
•
Check the phase direction upstream of the unit and in the
customer’s electrical data table.
•
Check the status of the contactors and fuses.
•
Carry out a quick test (refer to the BW10 Control manual).
Mechanical checks
•
Verify the correct operation of the evaporator and
condenser pumps with the Quick Test function.
•
Verify the correct operation of cooling fans, speed
converter and condensing pumps.
Water circuit checks
•
Check the leak-tightness of the circuit.
Service C
Carry out the operations listed under Service B.
Refrigerant circuit
•
Check the leak-tightness of the circuit and ensure that
there is no piping damage.
•
Carry out an oil contamination test. If acid, water or
metallic particles are present, replace the oil in the circuit.
•
Verify the tightening of the thermostatic mechanism of the
expansion device.
•
Full-load operating test. In addition to the checks carried out
under Service B, validate the value between leaving water
and the saturated evaporating temperature.
•
Check the operation of the high-pressure switch(es).
Replace them if there is a fault.
•
Check the fouling of the filter drier (by checking the
temperature difference in the copper piping). Replace it if
necessary.
Electrical checks
•
Check the status and insulation of the electrical cables.
•
Check the phase/earth insulation of the compressors and
pumps.
•
Check the compressor and pump winding status.
Mechanical checks
•
Check that no water has penetrated into the control box.
•
Clean the filter of the air inlet grille and if necessary
replace the filter.
Water circuit checks
•
Clean the water filter.
•
Purge the circuit with air.
•
Verify the correct operation of the water flow switch.
•
Check the status of the thermal piping insulation.
•
Check the water flow by checking the heat exchanger
pressure difference (using a pressure gauge).
•
Check the concentration of the anti-freeze protection
solution (ethylene glycol or polyethylene glycol).
•
Check the heat transfer fluid staus or the water quality.
•
Check the steel pipe corrosion.
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