Hoshizaki TempGuard FH1-SSB, Service Manual, Page: 34 / 63

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C. 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. Install the new drier with the arrow
on the drier in the direction of the refrigerant flow.
1) Unplug the unit from the electrical outlet.
) 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 50°F (11°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 1 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.
1) Replace the panels in their correct positions.
13) Plug the unit back in.