Movincool CM 25 Manuel de service télécharger pdf (Page 78)

Repair Section

8. REFRIGERATION SYSTEM REPAIR

WARNING

• Disconnect power supply from the unit before performing any service. Beware that some

residual voltages may remain in the unit immediately after the power is disconnected.

8.1 Repair of Refrigeration System

• In case there is a leak, obstruction, or trouble in the refrigeration system, replace or repair the

part in question. After replacing any component all connections must be brazed.

(1) Proper brazing techniques

• It is desirable to use a slightly reduced flame. Oxyacetylene is commonly used since it is easy

to judge and adjust the condition of the flame. Unlike gas welding, a secondary flame is used for

brazing. It is necessary to preheat the base metal properly depending on the shape, size or

thermal conductivity of the brazed fitting.

• The most important point in flame brazing is to bring the whole brazed fitting to a proper brazing

temperature. Care should be taken to not cause overflow of brazing filler metal, oxidation of

brazing filler metal, or deterioration due to the overheating of flux.

(2) Brazed fittings and fitting clearance

• In general, the strength of brazing filler metal is

lower than that of the base metal. So, the

shape and clearance of the brazed fitting are

quite important. As for the shape of the brazed

fitting, it is necessary to maximize its adhesive

area. The clearance of the brazed fitting must

be minimized to facilitate brazing filler metal to

flow into it by capillary action.

I002225

Clearance

Clearance From The Pipe Fitting and Tubing.

0.001~0.003 in

(0.025~0.075 mm)

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Movincool CM 25 Manuel de service Page 78