Equator 375 service manual Close the valve

2.1.1.Opening the Refrigerating System for Repairs with Recovery of Refrigerant.

If a hermetic refrigerating system is to function correctly and have a reasonably long life, it is essential that the amount of impurities pre-sent in the system, i.e. moisture, foreign gases, dirt, etc., be kept at a minimum.

This fact must be taken into consideration when repairs are to be made, and the necessary precautions must be taken. Before commencing repairs, make sure that all other possible faults have been eliminated and that an exact diagnosis of the problem has been made.

Mount a service valve or drilling tongs on the charging pipe (process pipe) and confirm the diagnosis with a suction mano- meter.

Close the valve.

After thorough cleaning of the spot where the gasket of the drilling tongs is to seal and adjusting of the tongs into filter size(if the tongs are tightened too much, the filter will be deformed the drilling tongs are mounted on the top of the filter drier just below the curve (at the pressure pipe - see fig. 1.) and drill the filter. Mount the hose on the threaded branch of the drilling tongs. After the mounting of the refrigerant bag, the valve on the drilling tongs is opened, and the refrigerant will pressurequalize into the refrigerant bag. After the pressure equalization the valve is closed, and the refrigerant bag is dismounted and mounted on the vacuum pump outlet - see fig.

4.Connect the hose for the filling station on the valve for the filter and open the valve - see fig. 5 and 6. The refrigerating system is now ready for the first evacuation with recovery of refrigerant. Evacuate to a pressure of approx. 1 mbar. There must not be any appreciable overpressure in the refrigerant bag, as this may damage the vacuum pump. When changing refrigerant bag the evacuation is stopped by closing the valve for the vacuum pump. After the evacuation the valve is closed at the filter drier. Dry nitrogen (N) is connected to the valve on the process pipe and the pressure is equalized - see fig. 7 and 8. Plan the repair work so that the refrigerating system will not be open for more than 10 - 15 minutes.

Assemble the special equipment required for the repairs. Assemble any spare parts required.

Open the system by breaking off the capillary tube at the filter drier. This is done using special-purpose pliers or capillary tube scissors, so that burrs and deformation of the tube are avoided.

Cut out the filter drier with a pipe cutter - see fig. 9. The filter must never be soldered off, as any moisture collected in thefilter will evaporate and be pressed back into the system,where it can later lead to the formation of ice in the capillary tube. Blow dry nitrogen (N) through the process pipe and into the system. The inlet pressure should be approx. 5 bar.

Continue blowing for 1 - 2 minutes. This creates an inactive atmosphere, which is a pre-requisite if soldering is to be carried out.

The blowing process also allows the localization of any obstructions in the piping.

Investigate the filter as well for possible blockage.

The refrigerating system is now ready for soldering.

Any leakages can be remedied and components remounted. All pipes which have been cut over (eg. when replacing the compressor) must be plugged during the repair work. See Sections 2.2.: Replacing the Filter Drier, 2.3.: Replacing the Compressor and 2.4.: Replacing the Evaporator.

Solder on the pipes and blow 2 through the system again. Use special-purpose pliers to make a wave in the capillary tube (2.2.).

Mount a service filter which is larger than the filter originally used (as specified in the spare parts list). The filter drier must be hermetically sealed until it is mounted.

When soldering the filter, note that the thin capillary tube cannot with-stand high temperatures due to the risk of melting and that heating must therefore be confined to the filter. Evacuate the system through the process pipe to a pressure of ap-prox. 1 mbar. Rinse thereafter with approx. 309 refrigerant. This causes any moisture or non-condensable gases present to be mixed together and discharged.

By letting the compressor run warm, this process can be furthered. With very contaminated systems, the above process must be repeated several times.

The system is now ready for the actual evacuation. Evacuate until a stable vacuum of 1 mbar has been reached. Check for stability of the vacuum by closing the valve for the vacuum pump. If the vacuum gauge needle falls appreciably, possible leakage in the system is indicated.

When a stable vacuum of 1 mbar has been achieved, close the valve for the vacuum gauge and commence charging.

Switch on the heating element for the filling glass. Read the manometer on the filling glass and select the column height. The amount of refrigerant to be added is specified in grams on the rating plate. Fill the unit with the exact amount and start the compressor.

Use the suction manometer to check for correct charging.

Mounting of Drilling Tongs on Filter Drier.

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