1.0 General Checking
- Check evaporator and condenser pressure and temperature in/out at the gauges, and thermometer and record the reading (The reading must be within the manufacturer’s range).
- Visually inspect the refrigerant filter for any frost formation.
- Visually inspect the oil filter pressure drop indicator.
- Check all refrigerant and oil levels as recommended by the manufacturer.
- Check all seals, valves, fittings, and pipelines for water leakage.
- Check all safety devices’ operation and clean, adjust, and lubricate as necessary.
- Check the suction, discharge, and oil pressure of all refrigerant compressors.
- Check all bolt nuts, mounting springs, and brackets for tightness and tighten as necessary.
- Check the operation of the oil pump unit.
- Test vent piping of all relief valves for the presence of refrigerant to detect improperly sealed relief valves.
- Inspect both Chiller and Condenser tubes.
- Check the oil level and refrigerant charge for the compressor.
- Check the overall electrical panel (thermostat, relay, overload, contactors and etc), wiring for tightness, and tighten as necessary.
- Check compressor voltage, and current running ampere and record the reading (The reading must be within the manufacturer range).
2.0 Compressor Checking
Oil Filter – The oil filter must be changed when the oil pressure drop 30% or semi-annually if not required earlier. When the oil filter is changed it should be inspected thoroughly for any Aluminium particles which would indicate possible bearing wear.
Oil Changing – The oil in the compressor must be changed annually or earlier if it becomes dark or cloudy.
2.2 Compressor Motor
Check motor mounting screws frequently to insure tightness. Meg motor windings annually to check for deterioration of windings.
2.3 Pressure Testing
The unit should be pressure tested annually. Any leaks found must be repaired immediately. If frequent purging has occurred the unit must be pressure tested as soon as possible to prevent air and moisture from entering the system and experience has shown that units which are maintained tight are systems that will provide trouble-free efficient operation.
3.0 Cooler and Condenser
The major portion of maintenance on the condenser and cooler will deal with maintaining of the water side of the condenser and cooler in a clean condition. The use of untreated water in cooling towers, closed water systems, etc. frequently results in one or more of the following:
- Scale formation.
- Corrosion or Rusting.
Slime and Algae Formation.
It is therefore to the benefit of the user to provide proper water treatment to provide for the longer and more economical life of the equipment. The following recommendation should be followed in determining the condition of the water side of the condenser and cooler tubes.
- The condenser tubes should be cleaned annually or earlier if conditions warrant. If the temperature difference between the water off the condenser liquid temperature is more than 4° greater than the difference recorded on a new unit it is a good indication that the condenser tube requires cleaning.
- The cooler tubes under normal circumstances will not require cleaning. If however, the temperature difference between the refrigerant and the chilled water increases slowly over the operating season, it is an indication that the cooler tube may be fouling or that there may be a water by-pass in the water box requiring gasket replacement.
4.0 Purge Unit (Annually)
- Clean and inspect all valves which are part of the purge unit system.
- Drain and flush the oil and refrigerant from the purge unit shell.
- Before flushing remove the float assembly from the purge unit shell.
- Disconnect the oil line from the bottom of the purge unit shell.
- To clean – flush Refrigerant – 11 from the top of the purge unit shell and let the refrigerant drain from the bottom through the oil line connection.
- After complete flushing, replace the float assembly and the oil drain line.
- Clean the following orifice. One (1) orifice in the liquid feed line to the cooling coil.
- Inspect the foul gas inlet check valve.
5.0 Oil Return System
Change the dehydrator in the oil return system semiannually or earlier if the oil return system fails to operate.
When the dehydrator has changed the nozzle of the educator should be checked for any foreign particles that may be obstructing the jet.
6.0 Electrical Control
- All electrical controls part should be inspected for obvious malfunctions.
- It is important that the factory settings of controls (operation and safety) not be changed.