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2) Turn on the Vacuum Pump. Never allow the oil in the Vacuum Pump to flow backward.
3) Allow the Vacuum Pump to pull down to a 29.9" Hg vacuum. Evacuating period de-
pends on pump capacity.
4) Close the Low-side Valve and High-side Valve on the Service Manifold.
5) Disconnect the Vacuum Pump, and attach a Refrigerant Service Cylinder to the
High-side line. Remember to loosen the connection, and purge the air from the
Hose. See the Nameplate for the required refrigerant charge. Hoshizaki recom-
mends only virgin refrigerant or reclaimed refrigerant which meets ARI Standard
No. 700-88 be used.
6) A liquid charge is recommended for charging an R-404A system. Invert the Service
Cylinder. Open the High-side, service manifold Valve.
7) Allow the system to charge with liquid until the pressures balance.
8) If necessary, add any remaining charge to the system through the Low-side. Use a
throttling valve or liquid dispensing device to add the remaining liquid charge
through the Low-side access port with the unit running.
9) Close the two Refrigerant Access Valves, and disconnect the Hoses and Service
Manifold.
10) Cap the Access Valves to prevent a possible leak.
2. BRAZING
DANGER
1. Refrigerant R-404A itself is not flammable at atmospheric pressure and
temperatures up to 176° F.
2. Refrigerant R-404A itself is not explosive or poisonous. However, when
exposed to high temperatures (open flames) R-404A can be decom-
posed to form hydrofluoric acid and carbonyl fluoride both of which are
hazardous.
3. Always recover the refrigerant and store it in an approved container. Do
not discharge the refrigerant into the atmosphere.
4. Do not use silver alloy or copper alloy containing Arsenic.
5. 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 refrig-
erant, raising the pressure with nitrogen and using an electronic leak
detector.