Stabilizing the System

Stabilizing the System

1. Accurate test gauge data will only be attained if the system temperatures and pressures are stabilized.

Ensure that equipment and hoses cannot come into contact with engine moving parts or sources of heat.

It is recommended that a free standing air mover is placed in front of the vehicle to provide air flow through the condenser/cooling system.

Start the engine, allow it to attain normal working temperature and set at fast idle (typically 1200 to 1500 rpm).

Select full air conditioning performance.

With all temperatures and pressures stable, or displaying symptoms of faults; begin relevant test procedures.

Graph - High Side Pressure/Ambient Temperature:

7. The 'Normal' condition is that which is relevant to the prevailing ambient temperature.

Graph-Low Side Pressure against Evaporator Temperature:

8. (To obtain lbf/in2 from bar, multiply the figure by 14.5)
Probable causes of faults may be found by comparing actual system pressures, registered on your manifold gauge set or recovery/recharge/recycle station, and the relevant pressure to temperature relationship graph. The following chart shows the interpretation that may be made by this difference.


NOTE: The A/CCM will disengage the compressor clutch should the evaporator temperature fall to 0° C.


NOTE: Graphs are typical for HFC 134A


The 'Normal' condition is that which is relevant to the prevailing evaporator temperature.