Hoshizaki C-101BAH Service Manual page 22

2. Brazing
• R-134a itself is not flammable at atmospheric pressure and temperatures up to
212°F (100°C).
• R-134a itself is not explosive or poisonous. However, when exposed to high
temperatures (open flames), R-134a can be decomposed to form hydrofluoric
acid and carbonyl fluoride both of which are hazardous.
• Do not use silver alloy or copper alloy containing arsenic.
1) Braze all fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG.
• 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.
• 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).
2) 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-134a as a mixture with
pressurized air for leak testing.
3. Evacuation and Recharge (R-134a)
1) Attach a vacuum pump to the system. Be sure the high-side charging hose is connected
to the field-installed high-side access valve.
The vacuum level and vacuum pump may be the same as those for current
refrigerants. However, the rubber hose and gauge manifold to be used for
evacuation and refrigerant charge should be exclusively for POE oils.
2) Turn on the vacuum pump, then open the high-side valve on the gauge manifold. Never
allow the oil in the vacuum pump to flow backwards.
3) Allow the vacuum pump to pull down to a 29.9" Hg vacuum. Evacuating period depends
on pump capacity.
4) Close the high-side valve on the gauge manifold.
5) Disconnect the gauge manifold hose from the vacuum pump and attach it to a
refrigerant service cylinder. Remember to loosen the connection and purge the air
from the hose. For the required refrigerant charge, see the nameplate. Hoshizaki
recommends only virgin refrigerant or reclaimed refrigerant which meets ARI Standard
700 (latest edition) be used.
WARNING
NOTICE
IMPORTANT
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