Trane TRG-TRC012-EN notes

TRG-TRC012-EN 29

period four

Maintenance Considerations

notes determine the level of water treatment required to remove contaminants from

the cooling tower water.

Scale deposits are best removed by chemical means. The water-cooled

condenser is commonly isolated from the rest of the cooling tower water circuit

by valves, and a pump circulates cleaning solution through the condenser

tubes.

Sludge is removed mechanically. This involves removing the water boxes from

the condenser and loosening the deposits with a stiff-bristled brush. The

loosened material is then flushed from the tubes with clear water. As part of this

procedure, the strainers on both the chilled water and cooling tower water

circuits should be cleaned every year.

Every 3 years, or more frequently for process or critical applications, it is

recommended that a qualified service organization perform non-destructive

tube inspections on both the evaporator and condenser tubes. The eddy-

current tube test is a common method.

Rarely, problems may arise that cause refrigerant or water leaks. These must be

repaired immediately.

For air-cooled chillers, the condenser coils should be cleaned at least annually

in order to maintain proper efficiencies and operating conditions. Follow the

manufacturer’s instructions to avoid damage to the coils.

Probably the most important annual maintenance task required for helical-

rotary water chillers is an oil analysis. It may be conducted more frequently for

chillers that run continuously or more often than normal. This test, performed

by a qualified laboratory, verifies the integrity of the refrigeration system by

testing the moisture, acidity, and metal concentration levels. This analysis can

determine where problems exist or could potentially develop. By taking oil

samples on a regular basis, normal operating trends for the compressor and

bearing metals can be analyzed. As opposed to changing the oil once a year

whether it needs it or not, regular oil analyses can be used to determine proper

oil change intervals as well as predict major problems before they occur.

maintenance considerations

▲Oil analysis

◆Conduct annual analysis to verify

system integrity

◆Measure oil pressure drop to

determine if filter needs changing

◆Measure charge

▲Refrigerant charge

◆Measure charge and trim as

necessary

◆Measure superheat and subcooling

Figure 43