AEC ACOA Series Air-Cooled Central Chillers - Manual (Page 46)

7 Maintenance
7-1 Making Periodic Inspections
A program of regular inspection, cleaning and preventive maintenance by trained personnel will
contribute greatly to the long satisfactory service life of your ACOA central chiller.
Read essential temperatures and pressures periodically to see that they indicate normal operation.
Record these readings on a log sheet. Refer to the sample log sheet on Page 52. If any abnormal
operation is observed, try to determine cause and remedy it. See Chapter 8 on Page 49 for more
information on troubleshooting.
7-2 Making Monthly Inspections
• Wipe down external surfaces on the unit.
• Shut down the unit, open the main disconnect, and inspect the control panel, checking for
loose wires, burned contacts, signs of overheated wires, etc.
• Restart the unit and check performance of controls.
• Check sight glasses for proper refrigerant charge.
7-3 Maintaining the Evaporator and Condenser
The efficient performance of evaporator and condenser heat transfer surfaces is essential for
efficient performance of your ACOA central chiller. If these surfaces accumulate a film of dirt,
scale or slime, performance efficiency degrades substantially. The refrigerant side of heat
transfer surfaces does not foul, since refrigerant is a good solvent and it is in a closed, filtered
cycle.
Water side surfaces can foul from the water system. A program of water treatment can slow the
rate of fouling on heat transfer surfaces, but not eliminate it.
7-4 Cleaning the Evaporator
You can detect the effects of fouling by recording full load performance data on the log sheet. If
the difference between leaving water from the evaporator and saturated suction temperature at
the compressor is 2º greater than the difference recorded at clean conditions, the tubes should be
cleaned. You should clean the evaporator water side surfaces at least annually, and more often
if you use severely fouled water. Do this cleaning with the appropriate cleaning chemicals.
ACOA Series Air-Cooled Central Chillers
Page 45