Some things to know about R134a refrigerant

R134a refrigerant is a lighter and more popular medium to low temperature refrigerant due to its excellent overall performance and is therefore an effective alternative to R12 refrigerant in many areas where R12 is used. r134a refrigerant is known as difluoromethane in Chinese and has the chemical molecular formula CH2FCF3, as R32 refrigerant with a molecular weight of 52 but a standard boiling point of -26.1 It has a molecular weight of 52 and a standard boiling point of -26.1.

Main differences between R134a and R12 refrigeration systems

a. The container for R134a is light blue, while the container for R12 is white.

b. The connection hoses for R134a refrigeration systems are made of rubber and nylon with Society of Automotive Engineering (S.A.E. # J2196) seals; however, the connection hoses for R12 refrigeration systems are usually made of universal rubber hoses.

c. R134a refrigeration system connection hoses are colour coded (blue with black stripes for low pressure hoses, red with black stripes for high pressure hoses and yellow with black stripes for common hoses), but R12 refrigeration system connection hoses are not.

d. The R134a refrigerant inlet uses quick couplings, while the R12 refrigeration system uses threaded couplings.

e. The fitting connecting the hose to the instrument for the R134a refrigeration system has a 1/2" thread and the fitting for the high pressure port is larger than the fitting for the low pressure port; the R12 refrigeration system has a 7/16" thread at the connection between the hose and the instrument.

f. Compared to the R12 refrigeration system, the R134a refrigeration system has higher pressures and temperatures and requires a larger cooling fan.

Precautions in the use and maintenance of R134a

A. Instruments, equipment and gauges used for R134a cannot be interchanged with those used for R12 because if R12 is mixed with R134a, it will damage the compression surface and may also damage the use of instruments and equipment.

B. R134a and R12 refrigerant refrigerant oil cannot be mixed, because R134a and R12 refrigeration system refrigerant oil is not compatible. r12 refrigeration system generally uses domestic 18, 25 refrigerant oil, while R134a system generally uses synthetic PAG (polyethylene glycol (PAG) oil or polyester POE (polyester) oil.

C. Wear safety glasses and gloves when servicing refrigeration systems to avoid contact of liquid refrigerant with the skin, especially the hands and eyes, to avoid frostbite.

D. Similar to PAG oil and R134a, two layers of separation (between them) occur in the high and low temperature zones (Figure 1). For this reason, when filling R134a, it needs to be heated in a container containing hot water, but the temperature should not exceed 40. Heating with a heating device such as a burner is prohibited. Try to prevent the separation of the two layers, as this may have a negative effect on the compressor discharge pressure and cooling.

E. Use special seals and gaskets for R134a systems. The cooling oil used will cause the seals and gaskets used in R12 systems to blister and fail, resulting in refrigerant leakage.

F. When filling with R134a, the container containing R134a should be kept in an upright position to ensure that R134a enters the system in a gaseous state, otherwise R134a may enter the compression surface in a liquid state, which could damage the compressor. In addition, the filling operation should be carried out in an area with good air circulation to prevent the operator from being asphyxiated by the oxygen in the cylinder.

G. Store the liquid storage dryer (or gas-liquid separator) hermetically and install it quickly; otherwise the air entering the liquid storage dryer (or gas-liquid separator) will weaken the temperature absorption capacity of the desiccant and even fail.