A/C - R134a Service Precautions/Parts Differences
Bulletin No.: 003/93Issued: 9/7/93
Revised: 11/26/93
Category
U
Applicable Model/s
See Below
Subject:
R134a SERVICE PRECAUTIONS AND PARTS COMPARISON
The revised portion of this bulletin is indicated by asterisk(s). Replace the original bulletin with this revised copy.
*APPLICABLE MODELS/VINS
This bulletin contains information on R134a air conditioning systems. Vehicles produced prior to the dates listed have R12 systems. Refer to this chart to determine the vehicle's system.
DESCRIPTION
Starting with the 1994 626 model, Mazda will install air conditioning Systems that contain RlS4a refrigerant.
This bulletin will describe key differences between the R134a and R12 refrigerants and oils. Where possible, the bulletin also explains how to identify R134a components from R12 components. Information is listed in alphabetical order, refer to the index for specific bulletin items.
*ALPHABETICAL INDEX
OVERVIEW
R12 is currently being used in all Mazda air conditioning Systems. The 1994 model 626 will be produced with R134a air conditioning.
R12 refrigerant contains the chemical "chlorine". Chlorine is a contributor to ozone depletion. R134a does not contain chlorine and is considered ozone friendly.
WARNING
It accidental discharging occurs, ventilate the work area immediately before servicing. Additional health and safety information can be obtained from the refrigerant manufacturer.
Exposure to air conditioning refrigerant, lubricant vapor or mist can irritate eyes, nose and throat.
Avoid breathing air conditioning refrigerant, lubricant vapor or mist.
1. CHARGING VALVES
Charge ports have been redesigned to prevent refrigerant charging errors.
Identification:
R134a ports are female connectors, manufactured with no threads (quick connectors) and are larger in diameter than R12 ports.
2. COMPRESSORS AND COMPRESSOR OIL
R134a compressors have identification labels on the compressor body.
NOTE:
DO NOT use R12 compressor parts to repair R134a compressors, A/C system failure will result.
R12 compressor oil is mineral based and R134a compressor oil is synthetic.
Identification:
Refer to the labeling on the compressor oil container.
NOTE:
Each compressor has a label identifying which type compressor oil is required. Failure to follow this instruction can result in damage to the compressor and components.
R134a COMPRESSOR OILS ARE NOT IDENTICAL. Use only the R134a compressor oil specified for the compressor you are servicing. Refer to the lubrication requirements specified by the compressor manufacturer (see table).
Before recharging a R134a system, add the same amount of compressor oil that was removed during servicing.
R134a refrigerants and compressor oils attract and absorb moisture rapidly. Be careful to plug or cap lines, ports and containers after disconnection or opening. This will keep moisture and dust out of the system and container.
WARNING:
Never place used oil into a container with unused oil. Never place used oil into an air conditioning system. Do not reuse oil in the recovery/recycling/charging equipment.
R134a compressor oil will cause damage if allowed to stay in contact with a painted surface. If compressor oil does get on a painted surface, wipe it off immediately and flush the surface with water.
3. EVAPORATOR
No operational changes.
Identification:
R134a evaporators are manufactured with metric threads on the connectors.
4. EXPANSION VALVE
The expansion valve settings have been altered to maintain proper cooling.
Identification:
R134a expansion valves have "R134a" printed on the top.
5. FLEXIBLE HOSE
R134a air conditioning flexible hoses are made from nylon.
Identification:
Panasonic - R134a hoses have a green label at the end. R12 hoses have no marking.
Nippondenso - R134a hoses have the letter "LR" at the end. R12 hoses have no marking.
MANA AC Kits - R134a hoses have a blue label with "R134a" on the hose. R12 hoses have no marking.
6. JOINTS (Only for factory and Nippondenso A/C)
R134a components are redesigned to prevent R12 components from being installed in R134a systems.
Identification:
R134a joints are manufactured with a metric thread and larger diameters.
7. OIL SEAL/O-RING
The material used for R134a oil seal/o-ring production has changed from the R12 air conditioning systems.
Identification:
An R134a label appears on all parts packages.
NOTE:
To avoid system contamination, keep oil seals and o-rings in the package until installation.
R134a o-rings may be used in R12 systems but R12 o-rings can not be used in R134a systems.
8. PIPPING
No operational change.
Identification:
All R134a pipping with charge ports and/or pressure switches are tagged with a light blue label.
9. PRESSURE SWITCH
R134a air conditioning Systems operating pressures are higher than R12. The pressure switch for the R134a is calibrated for this higher pressure.
10. RECEIVER/DRIER
The moisture absorbing material used in the R134a receiver/drier is different than the R12 receiver/drier.
NOTE:
Due to the absorbing properties of the receiver/drier, sealing caps should be left in place until installation.
Identification:
Panasonic - R134a receiver/drier has larger diameter connectors and a green label on the receiver /drier. R12 receiver/drier has no markings.
Nippondenso - R134a receiver/drier has no identification marks or labels. R134a does have larger diameter connectors with metric threads. R12 receiver/drier has no markings.
MANA AC Kits - RlS4a receiver/drier has a R134a" designation. R12 receiver/drier has no markings.
11. REFRIGERANT
The chart identifies some of the differences in refrigerant designations, formula and containers.
12. SERVICE EQUIPMENT
Use only equipment which is U.L. listed and is certified to meet the requirements of SAE J2210 to remove R134a refrigerant from air conditioning Systems.
WARNING:
Some mixtures of air and R134a can be combustible at elevated pressures and can result in fire or explosion leading to injury and/or property damage. Never use compressed air for pressure testing R134a equipment.
Leak Detectors
R12 leak detectors are not calibrated to detect R134a refrigerant. Use only leak detectors designed for R134a systems to detect a R134a refrigerant leak.
Manifold Gauges
Use only manifold gauges designed for R134a systems. Never try to interchange parts between R134a and R12 gauges.
Vacuum Pumps
If a vacuum pump is used instead of the recovery/recycle/charging equipment, it must have a check valve installed to prevent the pump oil from back-flowing into the air conditioning system.