[B] Refrigerant Recovery; [C] Evacuation And Recharge - Hoshizaki FM-170AFE Service Manual

7) Evacuation, Vacuum Pump and Refrigerant Charge [R134a]
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
R134a.
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 R134a 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. No refrigerant Access
Valve is provided in the unit. Install a proper Access Valve on the low-side line (ex. Compressor
Process Pipe). Recover the refrigerant from the Access Valve, and store it in a proper
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 pump capacity.
4) Close the Low-side Valve on the Service Manifold.
5) Disconnect the Vacuum Pump, and attach either a Refrigerant Charging Cylinder with
visual weight indications or a Service Cylinder and electronic scales to accurately weigh
in the charge. Remember to loosen the connection on the Charging Hose to purge the
air. Check the Nameplate for the required refrigerant charge.
6) Open the Low-side Valve. Do not invert the Charging Cylinder. A liquid charge may
damage the Compressor.
7) Plug in the icemaker when charging speed gets slow. Unplug the icemaker when the
Low-side Gauge shows approximately 0 bar. Do not run the icemaker at negative
pressures. Close the Low-side Valve when the charging is complete.
8) Repeat the above step 7), if necessary, until the required amount of refrigerant has entered
the system.
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