[B] Refrigerant Recovery; [C] Evacuation And Recharge - Hoshizaki KMD-270AWA Service Manual

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 icemaker unit is provided with refrigerant access valve(s). Using proper refrigerant
practices, recover the refrigerant from the access valve(s) and store it in an approved
container. Do not discharge the refrigerant into the atmosphere.

[c] EVACUATION AND RECHARGE

1) Attach charging hoses, a service manifold and a vacuum pump to the system.
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 valve on the service manifold.
5) Disconnect the vacuum pump, and attach a refrigerant charging cylinder. Remember to
loosen the connection, and purge the air from the hose. See the nameplate for the
required refrigerant charge.
6) Open the low-side valve. Do not invert the charging 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 kg/cm
pressures. Close the low-side valve when the charging cylinder gets empty.
8) Repeat steps 4) through 7), if necessary, until the required amount of refrigerant has
entered the system.
9) Close the refrigerant access valve(s), and disconnect the hoses, service manifold, etc.
10) Cap the access valve(s) to prevent possible leak.
2
. Do not run the icemaker at vacuum
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