Visit or Refer to our website: www.godrejsmartcare.com training page for information on Godrej SmartCare technical training or contact any of our branches regarding training on Compressor Operations & Service Techniques (COST), as well as for service manuals, pocket books, good servicing practices and various service publications.

A complete charge of oil is 300 cc. It is necessary to make sure that adequate quantity of the oil remains in the compressor before installing it on to the refrigeration system.

The chemical and physical effects that could happen because of such materials on refrigerants, oil and other compressor materials cannot be known unless proper careful laboratory tests are conducted. We do not recommend use of these types of additives. Further the same may result in violating the warranty terms issued on compressor.

The appropriate method to establish compressor’s pumping is with use of a pair of pressure gages, an ammeter and the compressor specifications. Examine the operating discharge and suction pressure apart from current. Using the compressor specifications, compare these readings/observations at the actual pressures noticed during examination. Certainly due to variations in power - voltage and human errors while reading, inaccuracies in the measured current may be within +/- 12%. Do not check compressor operation by closing the suction valve to see the extent of minimum suction achieved as it may damage the compressor due to heat generated inside.

Do not test compressor in open with ordinary air. Instead use dry Nitrogen and adopt correct testing procedure as recommended by Godrej.

Normally this does not happen but in case this is noticed then it is suggested to reduce dimming of lights caused by drop in voltage while the compressor takes a start by adding a start capacitor to the electrical wiring. The capacitor will minimize the duration of the compressor being in locked rotor condition and thus minimize the period of bulbs dim to an acceptable level.

At the outset the noise is a subjective matter. In many cases, just replacing the compressor may not solve the noise problem. Hence it is suggested that all possible noise sources be studied carefully before replacement of compressor is thought about. The noise spread out by refrigeration system of a refrigerator or air-conditioner could be:

• Loosening or Vibration of parts fitted to system e.g. tubes, rear panels/sheet metal parts etc.

• Wearing out of mounting bushes

• Compressor noise as an in the air sound

• Outdoor/indoor fan (Aircons) or Air-cutting noise

At times, it is difficult to ascertain the origins of noise using the ear only. It may be useful to use noise tester i.e. dB meter for this purpose. In short, the compressor need not be considered as main noise creator. If it is heard only in IDUs or evaporators the noise could be due to running fan/blower motor or any object touching fan blade.

Possible causes could be:

• Over sized compressor for the heat load

• Undersized evaporator/suction line tubing

• The compressor shows a high to low internal leak

• In adequate power supply (voltage)

• Increase in operating pressures

• Faulty relay

• Faulty thermostat

Problem of overheating can occur when oil in a compressor is insufficient or heated to the point when it loses its ability to act as lubricant. If the heat is excessively high, chemically the oil breaks down. Other reasons for overheating due to discharge temperatures could be as under:

• Low suction pressure

• High condensing pressure

Low suction pressure is normally the result of pressure drop in suction line, light load operating conditions or choked/restricted evaporators. High condensing pressures can be taking place due to inadequate airflow around/through the condenser, undersized condenser, and overcharge of refrigerant or presence of non-condensable gases in the refrigeration system.

Pressure ratio to be high is a result of low suction pressure and/or high condensing pressure. If the compressor is operated within our specified limits, this condition will not arise.

For selecting a compressor the capacity is stated under specific test conditions like ISI (e.g. ISI conditions for air conditioning compressors is at 35oC ambient; 55oC condensing and 7.2^oC evaporating temperatures. ISI conditions for refrigerator compressors is at 32^oC ambient temperature; 55^oC condensing and –23.3^oC evaporating temperatures).

A capacity of a compressor will vary as per the load. To ascertain compressor capacity one needs to note the conditions he is operating at and state readings for comparison suitable for the specific compressor and refrigerant. This is not so easy and is not possible unless one has test lab as expected for standards.

Godrej recommended start devices should be used on any compressor – old type or new type. We have tested and approved the suitable start devices, list of which is given below.

For additional information contact your local authorized Service Spare-parts dealer or our branch office.

A drier/filter plays a vital role in refrigeration system. It is designed to be a device to clean a refrigerant while flowing through the system. We suggest that the drier/filter be installed between the condenser and capillary/liquid line. It should be fitted in slanting position in such a way that only liquid flows onwards or towards evaporator and the gas is not permitted to flow. This item must be replaced quickly once the system is opened for repairs/service.

At Godrej, we do not permit such direct replacement of refrigerant; especially when the original compressor/ refrigeration system was designed for R-12 and a technician want to charge R-134a into it. Instead refer to Godrej Training Manual TM-1005 wherein retrofitting is explained but the process is expensive and calls for extra care.

We do not permit, because

• it needs change of lubricating oil from mineral oil to Poly-ol Ester oil.

• the residuals of mineral oil may contaminate the system, which at a later date can damage the compressor.

• the capillary tube and even condenser may need change.

• Over & above cleanliness is of utmost importance while working with POE oils & R-134a refrigerant.

We do not sell the spare-parts of compressors, because their precise use with the help of necessary machinery and cleanliness is not easily available at most repairs shops. If these parts fail, the same usually damage the compressor, more which finally affect on compressor’s heat removal capacity, efficiency and/or additional component failures. Precisely for these reasons we supply new & repaired compressors.

A refrigeration compressor could be checked as per below given procedure.

• Connect the Nitrogen cylinder to the process tube of compressor using a double stage pressure regulator.

• Connect the discharge side of the compressor to a receiver or a condenser coil of appropriate capacity.

• To the other end of the receiver or condenser coil, connect a pressure gauge having a range of 0 to 300 psig.

• After connecting, check for leakage at all joints.

• Supply Nitrogen gas at a constant pressure of 20 psig in the process tube of the compressor.

• Start the compressor & run it for a few seconds to build up a head pressure of approximately 125 / 150 psig (Refrigerator / Air-conditioner compressor). On attaining the specified head pressure, stop the compressor.

• Wait for a minute & check for drop in head pressure. It should be within the specified limit of 30 / 40 psig (Refrigerator / Air-conditioner).

• In case the drop is more than the specified limit, the compressor is having pumping defect, or else the compressor is okay.

Most refrigerants have different
CFC 12 & HC refrigeration systems – Molecular Sieve size XH 5 – 10 grams
HFC 134a system - Molecular Sieve size XH 7 – 10 grams .
During servicing it is better to fit a drier/filter of higher grammage

It is simple task and can be performed as under. First it is better to understand the terminals sequence of Godrej Compressor.

Measure the resistance of windings as under.

• Insert black test lead into Common Terminal of multimeter/ohm meter & red test lead into ‘W’ Terminal.

• Set the function switch to the Ohm range

• Connect the test leads to the No.1 terminal & No.2 terminal of the compressor & note the value.

• Connect the test leads to the No.1 terminal & No.3 terminal of the compressor & note the value.

• Connect the test leads to the No.2 terminal & No.3 terminal of the compressor & note the value.

• Now you are ready to identify the compressor terminal sequence:
   - Highest Reading indicates the total of Run + Start winding resistance
   - 2nd Highest Reading indicates the Start winding
   - Lowest Reading indicates the Run winding
  Upon this you are now able to locate S, C, R terminals of compressor.