COUPLING AS 3599855 - Caterpillar

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(1) Factory installed identification tag
(2) Retrofit tag that is installed by the dealer One may also identify the type of refrigerant that is used in the air conditioning system by examining the charging ports. Systems with R-134a will use ports that are quick disconnect (4) while systems with the older R-12 will use threaded ports (3). These ports are usually found in the block fittings that attach to the compressor.
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(3) R-12 charging port
(4) R-134a charging port If the system contains R-12 and needs to be serviced, refer to Service Manual, SENR3334, "Air Conditioning and Heater R-12".If the system contains R-12 and needs to be retrofitted for use with R-134a, refer to Special Instruction, SEHS9734, "Retrofitting Caterpillar R-12 Air Conditioning System to R-134a Refrigerant".