– 15 –
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 R410A 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
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OUTDOOR unit
Gauge manifold
OUTDOOR unit
Refrigerant
cylinder
Electronic
balance
Electronic
balance
Siphon
R410A 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.
Fig. 3-4-2
Refrigerant
cylinder
3-5. Brazing of Pipes
3-5-1. Materials for Brazing
1. Silver brazing fi ller
Silver brazing fi ller 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 fi ller
Phosphor bronze brazing fi ller is generally used
to join copper or copper alloy.
3. Low temperature brazing fi ller
Low temperature brazing fi ller 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 fi ller 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 fi ller 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 fi ller.
3-5-2. Flux
1. Reason why fl ux is necessary
By removing the oxide fi lm and any foreign
matter on the metal surface, it assists the fl ow
of brazing fi ller.
In the brazing process, it prevents the metal
surface from being oxidized.
By reducing the brazing fi ller’s surface tension,
the brazing fi ller adheres better to the treated
metal.
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