[B] Refrigerant Recovery; [C] Evacuation And Recharge - Hoshizaki IM-240DNE Service Manual

type copper tubes are used in the shipped units.)
7) Evacuation, Vacuum Pump and Refrigerant Charge [R404A]
Never allow the oil in the vacuum pump to flow backward. The vacuum level and
vacuum pump may be the same as those for the current refrigerants. However, the
rubber hose and gauge manifold to be used for evacuation and refrigerant charge
should be exclusively for R404A.
8) Refrigerant Leak Check
Refrigerant leaks can be detected by charging the unit with a little refrigerant, raising
the pressure with nitrogen and using an electronic detector. Do not use air or oxygen
instead of nitrogen for this purpose, or rise in pressure as well as in temperature may
cause R404A to suddenly react with oxygen and explode. Be sure to use nitrogen to
prevent explosion.

[b] REFRIGERANT RECOVERY

The refrigerant must be recovered if required by an applicable law. A low-side access
valve is provided on an extension pipe connected to the suction port of the compressor.
A tap valve should initially be fitted to the high-side process tube to be replaced with a
proper access valve (see Fig. 11) when recovery is completed.
Recover the refrigerant, and store it in a proper container. Do not discharge the
refrigerant into the atmosphere.

[c] EVACUATION AND RECHARGE

1) Attach charging hoses, service manifold and vacuum pump to the low-side and high-
side (to be fitted by servicer) access valves.
2) Turn on the vacuum pump.
3) Allow the vacuum pump to pull down to a 760 mmHg vacuum. Evacuating period
depends on the pump capacity.
4) Close the low-side and high-side valves on the service manifold.
5) Disconnect the vacuum pump, and attach a refrigerant charging cylinder to
accurately weigh in the liquid charge. Remember to purge any air from the charging
hose. See the nameplate for the required refrigerant charge.
6) Open the high-side valve on the gauge manifold, and accurately measure in the
liquid charge. Close the valve on the charging cylinder before closing the high-side
manifold valve. Any remaining liquid in the line can be charged into the low side.
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