E. Removal and Replacement of Expansion Valve
IMPORTANT
Sometimes moisture in the refrigeration 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. Place the new expansion valve in position.
6)Remove the drier, then place the new drier in position.
7)Braze all fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG.
WARNING
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 (121°C).
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 expansion valve bulb to the suction line in the same location as the previous bulb. The bulb should be at the 12 o'clock position on the tube. Be sure to secure the bulb with the clamp and holder and to insulate it.
11)Place the expansion valve cover in position.
12)Replace the panels in their correct positions.
13)Turn on the power supply.
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