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Refrigerant
1. This ice machine uses R-404A or HP62 as a
refrigerant. It has several unique characteristics.
A. It is a near-azeotrope, and must be liquid
charged.
B. It must use polyol ester refrigerant oil, and that
oil is very water absorbent. The system must not
be open for more than 15 minutes.
C. An electronic leak detector capable of locating
HFC-134a type refrigerant must be used to locate
refrigerant leaks.
D. A special HFC type liquid line dryer must be
used.
E. When brazing, a dry nitrogen purge is required.
F. When evacuating, use of an electronic micron
gage is recommend. Evacuate to 300 microns.
Recovering the Refrigerant
Because of the check valves, liquid refrigerant
must be recovered thru the liquid line valve and
the low side access valve.
1. Low Side: Remove the stem cap and insert a
3/16" allen wrench. Check that the valve is closed.
Liquid Line: Remove the stem cap. Use a
refrigeration wrench and check that the valve stem
is fully UP or OUT. If recovering, remove the
schrod core before opening the valve.
2. Remove the port caps and attach refrigerant
manifold hoses.
3. Open the valves. Note: Open liquid line valve
half way to access both sides of the liquid line.
4. Recover the refrigerant using the normal
techniques for the recovery machine used.
Evacuation
Evacuate to 300 microns
Charging
1. Use an electronic scale to measure the charge.
2. Place a drum or cylinder of R-404A on the scale
in position to dispense liquid refrigerant.
3. A refrigeration manifold is assumed to 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. Be sure that the low side access valve is closed.
5. Open the discharge side manifold valve and
weigh in the name plate charge. After the charge is
weighed in re-check the scale.
Liquid Charging
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.
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.
December 2000
Page 35
CME456R
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