FILE NO. SVM-05026
– 11 –
1
Be sure to make setting so that liquid can be charged.
2
When using a cylinder equipped with a siphon, liquid can be charged without turning it upside down.
It is necessary for charging refrigerant under condition of liquid because R-410A is mixed type of refrigerant.
Accordingly, when charging refrigerant from the refrigerant cylinder to the equipment, charge it turning the
cylinder upside down if cylinder is not equipped with siphon.
Gauge manifold
Refrigerant
cylinder
Electronic
balance
OUTDOOR unit
[Cylinder with siphon]
[Cylinder with siphon]
[Cylinder without siphon]
Fig. 2-4-2
R-410A refrigerant is HFC mixed refrigerant.
Therefore, if it is charged with gas, the composition
of the charged refrigerant changes and the
characteristics of the equipment varies.
2-5. Brazing of Pipes
2-5-1. Materials f or brazing
(1) Silver brazing filler
Silver brazing filler is an alloy mainly composed of
silver and copper. It is used to join iron, copper or
copper alloy, and is relatively expensive though it
excels in solderability.
(2) Phosphor bronze brazing filler
Phosphor bronze brazing filler is generally used to
join copper or copper alloy.
(3) Low temperature brazing filler
Low temperature brazing filler is generally called
solder, and is an alloy of tin and lead. Since it is
weak in adhesive strength, do not use it for
refrigerant pipes.
1
Phosphor bronze brazing filler tends to react
with sulfur and produce a fragile compound
water solution, which may cause a gas leakage.
Therefore, use any other type of brazing filler at
a hot spring resort, etc., and coat the surface
with a paint.
2
When performing brazing again at time of
servicing, use the same type of brazing filler.
2-5-2. Flux
(1) Reason why flux is necessar y
•
By removing the oxide film and any foreign
matter on the metal surface, it assists the flow of
brazing filler.
•
In the brazing process, it prevents the metal
surface from being oxidized.
•
By reducing the brazing filler’s surface tension,
the brazing filler adheres better to the treated
metal.
Refrigerant
cylinder
Electronic
balance
Siphon
Gauge manifold
OUTDOOR unit
