Refrigeration System Service

NME454, 654 & FME504, 804

General: This ice machine uses R-404A refrigerant

Instructions for Liquid Charging R-404A

and polyolester oil. Do NOT use mineral oil in this

In preparation for charging, the low side hose

refrigeration system.

should have a sight glass, and/or a restricting

When the system is serviced, a special liquid

device (such as a “Charge Faster”) installed in it

line drier is required. It is included with

for metering liquid into the low side of the system.

replacement compressors.

1. After a thorough evacuation shut off the manifold

R-404A is not compatible with mineral oil so

valves and switch off the vacuum pump.

2. Place a drum of R-404A onto an electronic

these ice machines use Polyolester oil.

scale.

Polyolester oil absorbs water very easily. A

3. Attach the charging hose to the drum.

system opened for service must be re-sealed as

soon as possible (15 minutes maximum).

4. Open the valve on the drum and purge the

Special leak detection equipment is required to

charging hose.

5. Zero out the scale.

locate small refrigerant leaks. Usually a leak

6. Shut the low side access valve at the ice

detector capable of detecting a Halongenated

machine.

refrigerant or HFC-134a will work. Check with

7. Open the discharge manifold valve full open.

the leak detector manufacturer if in doubt.

Evacuate to 300 microns.

8. Watch the scale, when the correct charge is

shown, shut the manifold valve.

Liquid charge the system

Note: If all of the charge will not “go in” the

Access Valves: To use the

discharge side:

access valves:

A. Shut the discharge access valve at the ice

Remove the cap from the

machine.

stem, use a 3/16" allen

B. Switch the machine on.

wrench to check that the

C. Open the low side access valve at the ice

valve is CLOSED. The

machine.

remove the core cap.

D. Open the low side manifold valve and observe

Close the valve and

Torque stem

the sight glass to be certain that only gas is flowing

replace the caps when

into the system.

to 6-8 ft.-lb.,

done. The valve must be

caps to 7-12

E. When the proper charge is indicated on the

closed and the caps must be on or

ft.-lb.

scale, shut off the manifold valve(s).

the valve will

9. Shut off the valve on the refrigerant drum.

10. Re-open the manifold valves until all liquid has

flowed out of the hoses.

11. Shut the low side access valve on the ice

R-404A

machine.

Tank Must

12. Remove hoses from ice machine and replace

Be in Liquid

all caps.

Dispensing

Sight Glass

Position -

Check Tank!

SCALE

Hose Connection Schematic for Liquid Charging

January 2007

Page 31