Tool Briefing: A/C System Flushing

When an A/C system has suffered damage or been serviced improperly, it can cause confusing symptoms. Often the best way to diagnose a system is to return it to a known state of charge. Simply recovering the refrigerant and evacuating the system isn’t...


Hints for using the tools

When using the GE-48800 as a flush machine, first make sure that the oil separator’s drain bottle on the side of the machine is empty. This makes it possible to measure the amount of oil removed from the system during flushing. Also make sure that there is at least 10 pounds of refrigerant in the machine’s Internal Supply Vessel (ISV), often called the recovery tank. Finally, make sure the manual valve for the external refrigerant supply tank is closed. That’s because if electrical power is lost during the flush cycle, the machine’s electrically operated valves will be disabled. If the manual valve is open, refrigerant will flow from the supply tank into the recovery tank, making it impossible to recover refrigerant from the vehicle.

A separate flushing adapter is needed to connect the machine’s hoses to the vehicle’s hoses at the compressor block connection. The adapter kit is available from Robinair and other sources, and if you own the original GM J45268 Flush Adapter Kit, that will also work. The hoses can be connected so that refrigerant will flow in either direction, meaning the machine can be used to back-flush the system.

Read the User Manual

One of the machine’s automated features is a filter monitor. As spelled out in the SAE standard, the filter-drier must be replaced after 150 pounds of refrigerant has passed through it. Machines built to that Standard include software that monitors the quantity of refrigerant flowing through the filter, and once that maximum quantity has been reached, the machine will go into a forced stand-by mode. Before using the machine for anything at all, make sure there’s enough filter life to get through the job.

The user manual tells you how to find “filter capacity” data in the maintenance menu, how to change the filter and how to reset the filter monitor. The new filter has a serial number which must be entered on the keypad before the machine will reset and function normally again. While the details of filter replacement/reset procedures may differ with different manufacturers, similar filter capacity features are built into every RRR machine built to the SAE J2788 Standard.

As with any piece of shop equipment, it’s important to read the user’s manual carefully and make sure you understand how to use the machine before connecting it to the vehicle. This is even more important when complying with this particular TSB, because whether it’s the machine described here or any other new RRR machine, if it’s built to the latest SAE Standards, it will be different from any other machine you’ve ever used.

 

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