ELBOW ASSY 0957399 - Caterpillar

Note: The electrical power supply to the compressor should be switched OFF to perform this test.
Test the rotation. Rotate the compressor in the direction of belt travel by turning the nut on the end of the compressor main shaft. Rotation should be smooth with no binding.Rotation Checked? Yes/NoRotation Smooth? ____ (Yes) or (No)
Check the charge level confirmation. The air conditioning system must be correctly charged per Caterpillar specification or an incorrect diagnosis will occur. The best method to achieve the correct system refrigerant charge is by recovering, evacuating, and recharging with clean refrigerant to the correct level. Charging the A/C system must be conducted by weighing refrigerant with a calibrated scale to insure accuracy. Also, be sure to replace oil removed during refrigerant recovery with new oil. Reference SENR5664 for refrigerant charging procedures and capacity of CAT A/C systems.Charge Level Checked? Yes/NoOil Removed During Recovery: ____ (ml) or (oz)Refrigerant Charge Amount: ____ (Kg) or (lbs)
Test for low pressure. This test is best performed with the machine parked in the shade and with ambient temperatures less than 30 °C (86 °F). Close all cab doors and windows, block fresh airflow into the cab, and bypass the low-pressure switch (if the air conditioning system is so equipped). Start the machine and operate at high idle with the air conditioning switched ON and the cab blower set on low. Measure the low-side pressure at the refrigerant compressor after 10-15 minutes of operation. If the pressure reading is less than 69 kPa (10 psi) then the compressor suction valves are operating correctly.Low Pressure Checked? Yes/NoRecord Low Pressure Reading: ____ (kPa) or (Psig)Note: If cab temperature is above 25 °C (77 °F) when starting the test, the cab blower may require high-speed setting to reduce the temperature before starting the procedure.
Test for high pressure. Start the engine and set the speed at approximately 1200 rpm. Turn the air conditioner ON. Place a sheet of cardboard over the condenser to block airflow. Limiting the airflow over the condenser will cause compressor discharge pressure to increase. Check if the compressor discharge is able to increase up to 2414 kPa (350 psi). Once the specified pressure is reached, immediately remove the cardboard. If the compressor passes the test, the discharge valves are operating correctly.High Pressure Checked? Yes/NoRecord High Pressure Reading: ____ (kPa) or (Psig)The functional test is now complete. If this test procedure results in inconclusive results, your dealership's Technical Communicator can report the problem using the on-line Dealer Solution Network. The Dealer Solution Network will provide your Technical Communicator with additional troubleshooting support.Illustrations 1 through 4 are provided as Good Air Conditioning System Practices and Troubleshooting Tips.
Illustration 1 g01127048
Typical Refrigerant Compressor ( 3E-1906 Refrigerant Compressor Gp shown)
Illustration 2 g01123619
Wire lead and pin location for field coil
Illustration 3 g01126988
Permissible mounting orientation and location of Suction Port "S" and Discharge Port "D". (1) Suction Port "S" (2) Discharge Port "D"
Illustration 4 g01127111
On-Delay Timer Assembly (Compression Protection System)Procedure to Test the On-Delay Timer Assembly
In order to diagnose a faulty on-delay timer