VESSER CGU12N, Service Instructions Manual, Page: 67 / 177

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QSPEVDU
should use a pipe bender to bend pipes.
‹ Upward or longitudinal welding joint method is usually applied to the welding of pipelines. The welding
method that mouth of pipe is downward (face-down welding) should be avoided as far as possible,
because such method is prone to welding defects and even would cause leakage, as shown in Figure 3-1-
3.
Bumer
Solder
Downward facing
Side facing
Recommended methed
Upward facing
Figure 3-1-3
‹ Uninsulated connecting pipes and connectors should be packed with sponge and tied with plastic adhesive tapes.
2. Vacuum-pumping and leak detection
‹ Dismantle the bonnet of refrigerant valve and air valve.
‹ Align with the center of piping and adequately tighten nuts of connecting pipes by hand
‹ Tighten the nuts with a spanner.
‹ Remove the one way valve cap of air valve.
‹
Unscrew the spool of refrigerant valve for 1/4 turn with a socket head wrench, and at the same time push
up the spool of air valve with a screwdriver to let air give off.
‹ Air exhaust continues for 15 seconds until coolant gas appears, immediately shut off one way valve and
tighten the valve cap.
‹ Totally open the spool of refrigerant valve and air value (as shown in Figure 3-1-4)
One-Way Valve
Gas Valve
Liquid Valve
Valve Cap
Inner Hexagon
Spanner
Screwdriver
Valve Stem
Figure 3-1-4
‹ Tighten the valve caps and use soapy water or a leak detector to check any leakage on indoor unit,
outdoor unit and connection parts of pipes.
Caution
:
If conditions are allowed, a vacuum pump shall be used for drawing off air inside the system at a valve. Method for
creation of vacuum by using a vacuum pump is as follows:
‹ Take out the nut cover of the inlet for refrigerant.