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4) Close the low-side and high-side valves on the service manifold.
5) Disconnect the vacuum pump, and attach a refrigerant charging cylinder to accurately
weigh in the liquid charge. Remember to purge any air from the charging hose. See the
nameplate for the required refrigerant charge.
6) Open the high-side valve on the gauge manifold, and accurately measure in the liquid
charge. Close the valve on the charging cylinder before closing the high-side manifold
valve. Any remaining liquid in the line can be charged into the low side.
7) Do not charge more than 150 g of R290.
8) Turn on the icemaker. Release the high-side access connector, and allow pressure in the
charging line to slowly enter the low side of the system. Cap off the high-side access
valve. When pressure reduces on the low side, disconnect the low side charging line and
cap off the access valve.
9) Always cap the access valves to prevent a refrigerant leak.
10) Always thoroughly leak test all joints and valve caps.
11) Avoid charging large quantities of liquid into the low side in case of damage to the
compressor.
2. WELDING REPAIR FOR R290 REFRIGERATION CIRCUIT
1) Make sure the surrounding area of the unit to be repaired is free from ignition sources.
2) Open the window or operate the ventilator to make the surrounding area well-ventilated.
3) Connect the piercing valve. Recover the refrigerant in the specified manner or discharge
it into the atmosphere.
4) The refrigeration circuit pressure is back to atmospheric pressure. Pressurize the circuit
using nitrogen.
5) Discharge the pressurized nitrogen and recover the refrigeration circuit to atmospheric
pressure.
6) Repeat 4) and 5) above. Use a gas detector at the open end of refrigeration circuit to
detect any gas left inside the circuit.
7) Evacuate the refrigeration circuit for 30 minutes to remove any gas left inside the circuit.
