A/C Systems - R-134A Refrigerant Introduction
Group: CLIMATE CONTROLNumber: 93-97-003
Date: OCTOBER, 1993
Model: 1994 EXCEL, SCOUPE, ELANTRA
Subject
INTRODUCTION OF NEW A/C SYSTEMS WITH R-134a REFRIGERANT
1. DESCRIPTION
R-134a has been selected as an alternative refrigerant that has no ozone depleting potential, with similar thermodynamic properties to the current R-12 refrigerant.
There are important differences between these two refrigerants.
- Unlike R-12, R-134a contains no chlorine and has zero ozone depletion potential.
- A/C systems using R-134a generally operate at slightly higher pressures than R-12 systems.
- A synthetic polyalkylene glycol (PAG) oil also has been developed as a lubricant for the HFC-134a system. HFC-134a is not compatible with current mineral oils and it will lead to system failure if they are mixed.
This bulletin describes service precautions, and provides information about part changes, service tools and equipment needed to service this new A/C system.
2. SERVICE PRECAUTIONS
Basically, the service procedures for R-134a A/C systems are the same as for R-12 A/C systems, but the following should always be kept in mind:
- R-134a and R-12 A/C components are not interchangeable.
- Always use the recommended PAG oil when servicing an R-134a A/C system.
- When leak checking a R-134a A/C system, be sure that you are using an R-134a leak detector.
- An R-134a A/C system sight glass does not correctly indicate the amount of refrigerant charge. A charge machine or weight scale must always be used to charge with the proper amount of refrigerant.
3. PART CHANGES FOR R-134a
4. NEW SERVICE TOOLS FOR R-134a
- R-12 and R-134a require separate and non-interchangeable service tools and equipment because the refrigerants and lubricants are not compatible and must not be mixed even in the smallest amounts.
Never use the same set of equipments and tools for both R-12 and R-134a because all equipment contains residual amounts of refrigerant and lubricant. This may cause contamination of the A/C system.
- The use of incorrect equipment will result in refrigerant and/or lubricant contamination which may cause A/C system or service equipment failure.
4-1. Leak Detector
Current R-12 leak detectors will not detect R-134a, although some R-134a leak detectors will detect R-12 refrigerant.
NOTE:
Always refer to and follow the equipment manufacturer's recommendations when operating leak detectors.
4-2. Manifold Gauge Set
4-3. Recovery and Recycling Systems
During service of the automotive air conditioning systems, containment of refrigerant is important.
Hyundai recommends that a recovery/recycling system be used for any A/C related repairs requiring system recharging.
5. PRECAUTION FOR REFRIGERANT HANDLING
R-12 refrigerant and r-134a refrigerant must never be mixed, even in the smallest amounts, as they are incompatible with each other. If the refrigerants are mixed, system failure is likely to occur.
Use only the recommended lubricant for R-134a A/C systems and components. If lubricants other than the one recommended are used, system failure may occur.
the PAG lubricant absorbs moisture from the atmosphere at a rapid rate, therefore, the following precautions must be observed:
1. When removing refrigerant components from a vehicle, immediately cap the components to prevent moisture from entering the A/C system.
2. When installing refrigerant components on a vehicle, do not remove the cap until just before connecting the components.
3. Complete the connection of the refrigerant tubes and hoses quickly to prevent moisture from entering the A/C system.
4. Use the recommended lubricant from a sealed container.
If accidental system discharge occurs, ventilate the work area before resuming service.
6. EFFECTIVE PRODUCTION DATE
Beginning with 1994 model year production for:`
Excel
Scoupe
Elantra