Movincool CM25 Service Manual User Manual download pdf (Page 79)

Repair Section

(3) Cleaning brazing filler metal and pipe

• When the refrigeration system has been opened up, exposure to heat may have caused brazing

filler metal to stick to the inside and outside of the pipe. Brazing filler metal may also be

compounded with oxygen in the air to form oxide film. Fats and oils may stick to the pipe from

handling. All these factors can reduce the effectiveness of brazing. It is necessary to eliminate

excess brazing filler metal using sand paper, and by cleaning thoroughly with a solvent such as

Trichlene.

CAUTION

Do not use chlorine cleaner.

(4) Use of dry nitrogen gas

• During brazing, the inside of the pipe undergoes an oxidative reaction due to the brazing flame.

Introduce dry nitrogen gas {0.3 gal/min (1 L/min)}; adjust with the flow regulator} through the

pinch-off tube of the refrigerant.

< NOTE >

Take care not to allow dirt, water, oil, etc. to enter into the pipe.

(5) Vertical joints

• Heat the whole brazed fitting to a proper

brazing temperature. Bring the brazing filler

metal into contact with the fitting so that the

brazing filler metal starts flowing by itself.

• Stop heating the fitting as soon as the brazing

filler metal has flown into the clearance. Since

the brazing filler metal flows easily into portions

heated to the proper temperature, it is essential

to keep the whole fitting at the proper brazing

temperature.

I000564

Burner

45°

Tube

Brazing Filler Metal

Vertical Down Joint

I001725

Burner

45°

Tube

Brazing Filler Metal

Vertical Up Joint

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Movincool CM25 Service Manual User Manual Page 79