Removal And Replacement Of Expansion Valve - Hoshizaki KM1601SRH350 Service Manual

C. 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 supply.
) 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.
Always protect the valve body by using a damp cloth to prevent the valve from
overheating. Do not braze with the valve body exceeding 50°F (11°C).
8) Use an electronic leak detector or soap bubbles to check for leaks. Add a trace of
refrigerant to the system (if using an electronic leak detector), and then raise the
pressure using nitrogen gas (140 PSIG). DO NOT use R-404A as a mixture with
pressurized air for leak testing.
9) Evacuate the system, and charge it with refrigerant. For air-cooled and water-cooled
models, see the nameplate for the required refrigerant charge. For remote air-cooled
models, see the rating label inside the icemaker.
10) Attach the expansion valve bulb to the suction line in the same location as the previous
bulb. The bulb should be between the 10 and  o'clock positions 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.
1) Replace the panels in their correct positions.
13) Turn on the power supply.
IMPORTANT
CAUTION
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