Hoshizaki KM-250BWF - Manual (Page 33)

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2. Brazing
DANGER
1. Refrigerant R-404A itself is not flammable, explosive or poisonous.
However, when exposed to high temperatures (open flames), R-404A
can be decomposed to form hydrofluoric acid and carbonyl fluoride both
of which are hazardous.
2. Always recover the refrigerant and store it in an approved container. Do
not discharge the refrigerant into the atmosphere.
3. Do not use silver alloy or copper alloy containing arsenic.
4. Do not use R-404A as a mixture with pressurized air for leak testing.
Refrigerant leaks can be detected by charging the unit with a little
refrigerant, raising the pressure with nitrogen and using an electronic
leak detector.
Note: All brazing-connections inside the bin are clear-paint coated. Sandpaper the
brazing connections before unbrazing the components. Use a good abrasive cloth
to remove coating.
5) Disconnect the vacuum pump, and attach a refrigerant service cylinder to the
low-side line. Remember to loosen the connection, and purge the air from the
hose. See the nameplate for the required refrigerant charge. Hoshizaki
recommends only virgin refrigerant or reclaimed refrigerant which meets
ARI Standard No. 700-88 be used.
6) Open the low-side valve. Do not invert the service cylinder. A liquid charge will
damage the compressor.
7) Turn on the icemaker when charging speed gets slow. Turn off the icemaker when
the low-side gauge shows approximately 0 PSIG. Do not run the icemaker at
negative pressures. Close the low-side valve when the service cylinder gets empty.
8) Repeat the above steps 4) through 7), if necessary, until the required amount of
refrigerant has entered the system.
9) Close the two refrigerant access valves, and disconnect the hoses and service
manifold.
10) Cap the access valves to prevent a possible leak.