Hoshizaki F-450MAH - Manual (Page 39)

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1) Unplug the icemaker.
2) Remove the panels.
3) Recover the refrigerant and store it in an approved container, if required by an
applicable law.
4) Remove the expansion valve bulb at the evaporator outlet.
5) Remove the expansion valve cover, and remove the expansion valve using
brazing equipment.
6) Braze the new expansion valve with nitrogen gas flowing at the pressure of 3-4
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.
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 repairs or replacement have been made.
7) Install the new drier.
8) Check for leaks using nitrogen gas (140 PSIG) and soap bubbles.
9) Evacuate the system. Charge it with refrigerant. See the nameplate for the required
refrigerant charge and type.
10) Attach the bulb to the suction line. Be sure to secure the bulb using a band and
to insulate it.
11) Place the expansion valve cover in position.
12) Replace the panels in their correct position.
13) Plug in the icemaker.