CAMERA 5137310 - Caterpillar

Personal injury can result from contact with refrigerant.This system is under pressure at all times, even if the engine is not running. Heat should never be applied to a charged system.Contact with refrigerant can cause frost bite. Keep face and hands away to help prevent injury.Protective goggles must always be worn when refrigerant lines are opened, even if the gauges indicate the system is empty of refrigerant.Always use caution when a fitting is removed. Slowly loosen the fitting. If the system is still under pressure, evacuate the system recovering the refrigerant before removing the fitting.Personal injury or death can result from inhaling refrigerant through a lit cigarette.Inhaling air conditioner refrigerant gas through a lit cigarette or other smoking method or inhaling fumes released from a flame contacting air conditioner refrigerant gas, can cause bodily harm or death.Do not smoke when servicing air conditioners or wherever refrigerant gas may be present.Before any checks of the air conditioning and heating system are made, move the machine to a smooth horizontal surface. Lower all implements to the ground. Make sure the transmission is in neutral or park and that the parking brake is engaged. Keep all other personnel away from the machine or where they can be seen.
Personal injury can result from hot coolant. Any contact with hot coolant or with steam can cause severe burns. Allow cooling system components to cool before the cooling system is drained.
Never weld or solder any charged components.
Note: A performance check of the air conditioning system must be made with a manifold gauge set. Refer to the Testing and Adjusting, "Manifold Gauge Set - Install".Note: Before you conduct a performance test, refer to the Troubleshooting, "Visual Inspection".Note: The ambient temperature must be at least 21 °C (70 °F) in order to conduct the following test.
Install the manifold gauge set. Refer to the Testing and Adjusting, "Manifold Gauge Set (Refrigerant) - Install".
Start the engine and operate the engine at 1000 rpm (Low idle).
Move the temperature control knob to the maximum cool position. Put the fan switch in the HIGH position on the side that is for air conditioning.
In order to stabilize the system, continue to operate the system at 1000 rpm for a minimum of 10 minutes.
Adjust the engine speed to approximately 1300 to 1400 rpm. Record the readings on the gauge for discharge (high pressure), and on the gauge for suction (low pressure).
Compare the discharge and suction pressures on the manifold gauge set to the pressure ranges in Table 1 in order to determine if the system is functioning correctly for the current ambient temperature.
Table 1
Pressure Range (1)    
Ambient Air Temperature
C° (F°)     High Pressure Test Fitting
kPa (psi) (2) (4)     Low Pressure Test Fitting
kPa (psi) (3) (5) (6)    
21°C (70°F)    
820 to 1300 kPa (120 to 190 psi)    
70 to 138 kPa (10 to 20 psi)    
27°C (80°F)    
950 to 1450 kPa (140 to 210 psi)    
70 to 173 kPa (10 to 25 psi)