5. Removal and Replacement of Expansion Valve
IMPORTANT
Sometimes moisture in the refrigerant circuit exceeds the drier capacity and freezes up at the expansion valve. Always install a new drier every time the sealed refrigeration system is opened. Do not replace the drier until after all other repair or replacement has been made.
1)Turn off the power supply.
2)Remove the panels.
3)Recover the refrigerant and store it in an approved container.
4)Remove the insulation and the expansion valve bulb on the suction line.
5)Remove the expansion valve cover, and disconnect the expansion valve using brazing equipment.
6)Braze the new expansion valve, with nitrogen gas flowing at a pressure of
WARNING
1.Do not heat the wall. Place a steel barrier for protection.
2.Always protect the valve body by using a damp cloth to prevent the valve from overheating. Do not braze with the valve body exceeding 250°F.
7)Install the new drier.
8)Check for leaks using nitrogen gas (140 PSIG) and soap bubbles.
9)Evacuate the system, and charge it with refrigerant. For
10)Attach the bulb to the suction line in position. Be sure to secure it with clamps and to insulate it.
11)Place the new set of expansion valve covers in position.
12)Replace the panels in their correct position.
13)Turn on the power supply.
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