Hoshizaki KMD-410MAH Evacuation, Vacuum Pump and Refrigerant Charge R404A, Refrigerant Leak Check

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 valves. Using proper refrigerant practices, recover the refrigerant from the access valves and store it in an approved container. Do not discharge the refrigerant into the atmosphere.

[c] EVACUATION AND RECHARGE

1)Attach a vacuum pump to the system. Be sure to connect charging hoses to both high and low-side access valves.

2)Turn on the vacuum pump. Open the service manifold valves. Never allow the oil in the vacuum pump to flow backwards.

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 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. For air-cooled and water-cooled models, see the nameplate for the required refrigerant charge.

6)A liquid charge is recommended for charging an R-404A system. Invert the service cylinder and place it on scales. Open the high-side valve on the service manifold.

7)Allow the system to charge with liquid until the proper charge weight is met.

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 service manifold valves and disconnect the service manifold hoses.

10)Cap the access valves to prevent a possible leak.

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