Removal And Replacement Of Expansion Valve - Hoshizaki KM-251BAH Service Manual

E. Removal and Replacement of Expansion Valve
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.
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 then remove the expansion valve. Place the
new expansion valve in position.
6) Remove the drier (located below the expansion valve), 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.
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. See the nameplate for the required
refrigerant charge.
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.
IMPORTANT
WARNING
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