Toshiba RAV-SM1101BT-E, RAV-SM1400AT-E service manual Brazing of Pipes, Materials for Brazing, Flux

•Be sure to make setting so that liquid can be charged.

‚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.

[ Cylinder with siphon ]	[ Cylinder without siphon ]
Gauge manifold	Gauge manifold
OUTDOOR unit	OUTDOOR unit

Refrigerant

cylinder

Electronic balance

R410A refrigerant is HFC mixed refrigerant. Therefore, if it is charged with gas, the composi- tion of the charged refrigerant changes and the characteristics of the equipment varies.

cylinder Refrigerant

Electronic balance

Siphon

Fig. 7-4-2

7-5. Brazing of Pipes

7-5-1. Materials for 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 expen- sive 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.

•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.

‚When performing brazing again at time of servicing, use the same type of brazing filler.

7-5-2. Flux

(1)Reason why flux is necessary

•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.

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