Liquid Charging

CME1356R and CME1656R

Because R-404A is a near-azeotrope, only liquid refrigerant can be used to recharge the refrigeration system. To do that may take some special techniques:

1.Use an electronic scale to measure the charge.

2.Place a drum or cylinder of R-404A on the scale, valve side up (most R-404A disposable cylinders have an internal dip tube and dispense liquid refrigerant from the valve when it is upright - check yours).

3.A refrigeration manifold should be attached to the service access valves. Attach the charging hose to the cylinder of R-404A. Open the cylinder’s valve and purge the hose to the manifold.

4.Close the low side service access valve.

5.Open the discharge side manifold valve and weigh in the name plate charge. After the charge is weighed in, wait a few minutes and re-check the scale.

6.If all of the refrigerant charge has not been weighed into the discharge side, it must be carefully added thru the low side. Close the discharge service access valve.

7.With a sight glass or charge faster in the hose to the low side port, start the ice machine.

8.Open the low side service access valve.

9.Crack open the low side manifold valve and watch the scale and sight glass. Open and close the low side manifold valve to flow liquid into the manifold but flash off to vapor before it enters the suction side of the refrigeration system. This should only be a few ounces at most.

10.After the scale = the correct charge, shut off the valve on the refrigerant cylinder.

11.With the ice machine running and the discharge access valve closed, open both manifold valves to allow the refrigerant in the hoses to enter the system.

12.Shut the suction service access valve.

13.Remove the refrigeration manifold gages.

14.Replace and tighten all caps.

March 2003

Page 44