Hoshizaki FD-1001MWH(-C) EN - Manual (Page 84)

84
5. Removal and Replacement of Evaporator
CAUTION
1. Always install a new drier every time the sealed refrigeration system is
opened.
2. 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.
3. When brazing, protect the drier by using a wet cloth to prevent the drier from
overheating. Do not allow the drier to exceed 250°F (121°C).
1) Drain the water from the evaporator.
a) Move the power switch to the "OFF" position.
b) Move the control switch to the "DRAIN" position.
c) Move the power switch to the "ON" position and allow the water to drain from the
evaporator.
d) Move the power switch to the "OFF" position, then turn off the power supply.
2) Remove the panels.
3) Recover the refrigerant and store it in an approved container.
4) Remove the strap connecting the spout to the chute assembly, then remove the spout.
5) Disconnect the water hoses.
6) Remove the allen head cap screws securing the extruding head. Using the cutter, lift
out the auger assembly.
7) Remove the insulation and the expansion valve bulb on the suction line.
8) Disconnect the inlet and outlet tubing.
9) Remove the allen head cap screws securing the evaporator to the lower housing.
10) Lift off the evaporator.
11) Inspect the mechanical seal and O-ring prior to installing the new evaporator. The
mechanical seal consists of two parts. One moves along with the auger, and the other
is fixed on the lower housing. If the contact surfaces of these two parts are worn,
cracked, or scratched, the mechanical seal may cause water leaks and should be
replaced. Instructions for removing the mechanical seal and lower housing are located
later in this procedure.
12) Make sure the lower mechanical seal is in place, then place the evaporator in position.
Secure the evaporator to the lower housing using the allen head cap screws.
13) Remove the drier, then place the new drier in position.
14) Braze all fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG.
15) 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.