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Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017
♦ To ensure safety, only use compressed gas containers fitted
with a safety valve.
♦ Returnable and recycling cylinders must be weighed on suit‐
able scales during charging, or a method of charging by vol‐
ume must be employed to ensure that the permissible weight
of the filling specified on the tank/container is not exceeded.
The maximum permissible filling volume is 80% of the maxi‐
mum refrigerant volume of the filling weight specified on the
returnable and recycling cylinder or 70% of the maximum filling
volume (charge factor, the smaller of the values always ap‐
plies respectively). Reason: There is no way of absolutely
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ruling out refrigerant oil being filled into the returnable and re‐
cycling cylinder along with the refrigerant.
♦ There must be space both for liquid and vapour in a container.
As the temperature rises, the liquid expands. The vapour-filled
space becomes smaller. At a certain point, there will only be
liquid in the vessel. Beyond this, even a slight increase in tem‐
perature causes great pressure to build up in the vessel as the
liquid attempts to continue expanding despite the absence of
the necessary space. The resultant force is sufficient to rup‐
ture the vessel. To prevent containers from being over‐
charged, regulations governing the storage of compressed
gases specify how many kilograms may be charged into a
container for every litre of container volume. This charge factor
multiplied by the internal volume gives the permissible charge
quantity. The charge factor for refrigerant used in vehicles is
1.15 kg/litre.
♦ Since contaminated refrigerant could have a different density
than pure R1234yf refrigerant, the maximum permissible
charge factor must always be observed.
6.2.15
Evidence of leaks in a refrigerant circuit
with R1234yf refrigerant
♦ The refrigerant circuit could develop leaks, for example, from
the use of unsuitable or contaminated refrigerant or untested
materials in unsuitable components.
♦ Since a small leak will involve only small quantities of refrig‐
erant, evidence of leaks should be sought using an electronic
leak detector or by introducing a leak detection additive to the
refrigerant circuit. Electronic leak detectors can detect leakage
rates of less than 5 grams loss of refrigerant per year.
Note
Use must however be made of leak detectors designed for the
composition of the respective refrigerant. For example, leak de‐
tectors for R12 refrigerant are not suitable for R1234yf refrigerant
as these leak detectors do not always respond. Even leak detec‐
tors that are designed just for R134a refrigerant are not suitable
for R1234yf refrigerant because R1234yf refrigerant has a differ‐
ent chemical structure than R134a. Subsequently, these leak
detectors only respond to high concentrations of refrigerant in the
air or not at all ⇒ Electronic parts catalogue .
6.2.16
Analysis of refrigerant R1234yf
For operation of the air conditioning system, it is important that
the refrigerant used has a certain degree of purity.
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Rep. gr.00 - Technical data
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