Oil level in compressor: This should be about ½ of the sight glass. If this level is not maintained, it is a positive indication of malfunction in the plant. If the oil level in the compressor goes down, Never Fill in oil to make up the level. The only correct step is to find out the reason for the poor oil return and rectify it. Be alert to observe any unusual noise and vibration, it may ampify and cause serious problems. Check for overheating of any part of the plant.
Log books: Eventhough logging the readings is a part of the operation, it is these readings that tell the real condition of the plant if the readings show any abnormality, there is some malfunctioning somewhere and this has to be investigated and rectified without delay. The log book forms an important maintenance tool for day to day operation of the plant, as well as for future reference.

Weekly
Clean air filters: A dirty filter can reduce the plant capacity. More the dirt accumulation on the air filter, greater will be the reduction in capacity of the plant. Air filters, if not cleaned regularly will get saturated with dirt and thereafter dirt will pas on to the cooling coil fins, which will affect plant capacity much more and in extreme cases can even lead to liquid flood back to the compressor, which is highly injurious to the compressor.
Cooling coils being wet, this dirt/dust will form a crust on the coil. Hence, air filters are to be cleaned regularly . Weekly cleaning has been suggested; but where the plants are installed in dust environments, it may be necessary to clean the filters more often. Air filters should be changed, when it is found that cleaning does not remove all the dust.

Leak testing for refrigerant leak: A halide torch should be used to locate the leaks. Now electronic leak detectors are available. While leak testing, the approach should be to find a leak rather than taking it for granted that there won't be any leak and doing the work of leak test as ass ritual. Even a minor leakage can lead to lot of problems, such as poor oil return, heating of compressor apart from poor cooling. Further refrigerant is costly and so less leak/no leak becomes a big cost saving centre in the operation of the plant.

Water pump glands: Check for excessive water leak, through the pump land; certain amount of water drip through the gland is necessary to deep the gland cool. However, if the drip develops into regular flow, it is an indication that the gland is not holding well. The gland inputs can be tightened to reduce the leak, When tightening the nuts does not improve the situation, the gland packing has to be renewed. If this is not in time, water consumption will go up and in chilled water pump, a water leak means, loss of refrigeration.

Clean the water strainers: A clogged strained reduces water flow rate and thus affect the plant performance. Further, if the strainers are not cleaned regularly, the dirt/muck will form a crust and it becomes difficult to clean. This can even puncture strainer mesh, necessitating replacement of he strainer element. Though the strainer may look to be too small an item, it plays a very important role in keeping the heat exchanger surfaces clean and efficient.

Belt tension or belt drives: Check the tension of belts and lighten whenever found loose. A loose belt will reduce transmission efficiency and its own life will be educed. Further, the drive pulleys can get heated up. Replace belt when it is not possible to tighten them together. In multibelt drives, change he complete set of belts. Select the belts of matched set. If this is not done, the load will be taken only by the smaller length belts, thereby affecting transmission efficiency and belt life.

It is the pressure gauges and thermometers which give us a correct indication of the plant performance and condition. Therefore ensure that these are in good order.

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Check the spray of the cooling tower nozzles.
Drain, clean and refill the cooling tower sump, cooling towers being open, collect lot of dust and muck, hence the necessity to clear once in a week. The cooling tower water may require bleed off due to increased total concentration of the dissolved solids. Check the water hardness periodically.
Analyze the pressure and temperature readings of the plant from the log book and establish that the plant is working satisfactorily. Corrective action should be taken promptly when reading show even a minor malfunction.