10
3.
OPENING THE REFRIGERATION
SYSTEM
3.1
Flammable
refrigerants
Never open a refrigerating system before all components for the repair are available. The compressor, drier,
and other system components must be sealed off until a continuous assembly can occur.
Opening a defect system must be done in different ways depending on the refrigerant used. Fit a service
valve to the system and collect the refrigerant in the correct manner.
R600a and R290 are hydrocarbons. These refrigerants are flammable and are only allowed for use in appli-
ances which fulfill the requirements laid down in the latest revision of EN/IEC 60335-2-24. (To cover poten-
tial risk originated from the use of flammable refrigerants). Consequently, R600a and R290 are only allowed
for use in household appliances designed for this refrigerant and fulfill the above-mentioned standard.
R600a and R290 are heavier than air and the concentration will always be highest at the floor.
R600a must only be stored and transported in approved containers and must be handled according to exist-
ing guidelines.
The flammability limits are approx. as follows:
Refrigerant R600a R290
Lower limit 1.5 % by vol. (38g/m³) 2.1 % by vol. (39 g/m³)
Upper limit 8.5 % by vol. (203 g/m³) 9.5 % by vol. (177 g/m³)
Ignition temperature 460 °C / 860 °F 470 °C / 878 °F
In order to carry out service and repair on R600a and R290 systems, the service personnel must be properly
trained to be able to handle flammable refrigerants. This includes knowledge on tools, transportng the
compressor and refrigerant, and the relevant regulations and safety precautions when carrying out service
and repair. Do not use open fire when working with refrigerants R600a and R290!
Secop compressors for flammable refrigerants are provided with a special warning sign. The maximal filling
capacity is 150 g per system, which equates to approximately 8 g/m³ in a 20 m³ kitchen and thereby around
25 % of the lower flammability limit. These precautions minimize the risk of ignition in case of a leakage.
Under favorable conditions however, exceeding these values is officially allowed.
All manufacturers of HC-systems have to follow these safety regulations. Customer service, as well as
the repair of R600a and R290 applications, should only be accomplished by highly trained and experienced
personnel. This implies also knowledge about tools, transporting compressors and refrigerants as well as
laws, regulations, and standards.
National safety regulations demand leakage simulations and strictly require the isolation of electrical com-
ponents close to the flow of refrigerants.
Yellow warning labels
Conversions from refrigerants R12 or R134a to R600a is not permitted, as the refrigerators are not approved
for operation with flammable refrigerants, and the electrical safety has not been tested according to existing
standards either. The same applies to conversions from refrigerants R22, R502, or R134a to R290.
The smaller R290 compressors, types T and N, are LST types. These often need a timer to ensure sufficient
pressure equalization time.
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