Capacity of air conditioning systems - amounts of refrigerant and oil

We all know how important access to technical data is for a mechanic. The situation is no different in the case of a workshop servicing air conditioning in vehicles. Information about the size of the A/C system in the serviced car is crucial for its efficient operation.

A slightly higher amount (even more than 10%) of the refrigerant will not only result in a drastic decrease in the interior cooling efficiency, but above all will have a disastrous effect on the condition of the air conditioning compressor. Such action will soon result in a costly failure.

Understanding these threats and market needs, we encourage you to use the technical material and link below. There you will find information about the amount of refrigerant that should be filled in the air conditioning system, but also about the type and amount of oil used in it.

The following information and practical tips have been prepared by HELLA to provide professional support to car repair shops. The information provided on this website should only be used by suitably qualified personnel.

AIR CONDITIONING SYSTEM CAPACITIES: OIL REFRIGERANT QUANTITY   CHECK

REFRIGERANT R12, R134A, R1234YF: WORTH KNOWING.

There are still many vehicles on the market equipped with air conditioning originally adapted to the R12 refrigerant. 2001 was officially the last year of use of R12 in automotive air conditioning systems. From this year, systems filled with R12 are subject to mandatory modification as part of inspections or repairs. The R134a refrigerant was and is used as a replacement refrigerant, in addition to various "alternative" refrigerants (mixtures of refrigerants). The possibility of rebuilding air conditioning systems to use refrigerant 134a instead of R12 is an ongoing issue for owners of older vehicles and in some non-EU countries.

As part of the renovation, the installation should be checked for tightness. First, you need to eliminate leaks. All structural elements should be checked for proper operation and damage. Replace the filter-drier. Replace sealing rings. Additionally, replace the mineral oil of the R12 system with PAG or PAO oil. As part of this operation, the air conditioning should also be flushed.

The R134a refrigerant has a high global warming potential (GWP) of 1,430. The current Directive 2006/40/EC stipulates that in the future only refrigerants with a GWP of less than 150 will be used.

Air conditioning systems for class M1 vehicles (passenger cars, vehicles used to transport people with a number of seats less than or equal to 8) and class N1 (commercial vehicles with a permissible total weight of up to 3.5t), which were approved in the EU after January 1, 2011. , R134a refrigerant must therefore no longer be filled. From January 1, 2017, vehicles with systems filled with R134a refrigerant can no longer be homologated. However, the use of R134a refrigerant is still allowed for service and maintenance work on existing installations containing R134a refrigerant. The new refrigerant used is R1234yf with a GWP of 4. It is also possible to use other refrigerants, as long as their GWP is below 150. In the future, it remains to be seen whether all vehicle manufacturers will use the same or different refrigerants.

This will naturally have an impact on workshops and their staff. The purchase of new service equipment seems inevitable. Of course, special precautions must also be taken when storing and handling new refrigerants.

REFILLING REFRIGERANT - SAFETY RULES AND HANDLING OF REFRIGERANT: TIPS FOR WORKSHOPS

When topping up the refrigerant and performing any work on the refrigerant circuit, the following rules must be observed:

• Always wear safety glasses and gloves! At normal atmospheric pressure and normal ambient temperatures, the liquid refrigerant evaporates so quickly that its contact with the skin or eyes may cause tissue freezing (danger of loss of vision).
• In case of contact, wash the affected areas with plenty of cold water. Do not rub. See a doctor immediately!
• When working on the refrigerant circuit, the workplace must be well ventilated. Inhaling large amounts of refrigerant gas may cause vomiting and suffocation. Work on the refrigerant circuit must not be carried out from the ducts. Because refrigerant gas is heavier than air, it can accumulate there in high concentrations.
• Do not smoke! Cigarette embers can cause the refrigerant to decompose into poisonous substances.
• Do not allow the refrigerant to come into contact with open flames or hot metal. This may result in the formation of poisonous gases.
• Never allow refrigerant to escape into the atmosphere. When a refrigerant container or air conditioning system is opened, its contents escape under high pressure. This pressure depends on temperature. The higher the temperature, the higher the pressure.
• Avoid the impact of high temperatures on air conditioning structural elements. After painting work, vehicles must not be heated to a temperature higher than 75°C (drying oven). Otherwise, you need to empty the air conditioning first.
• When disconnecting service hoses from the vehicle, ensure that the connections are not directed at the body. Residual refrigerant may leak from the connectors.
• When cleaning your vehicle, do not aim steam cleaners directly at air conditioning parts.
• Do not under any circumstances change the factory setting of the adjustment screw on the expansion valve.