Mueller E-Star OESE 7.5 and 9 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828748
Effective June 16, 2020
3.3
WEIGH-IN REFRIGERANT CHARGING (CONTINUED)
6. When the system pressure equalizes with cylinder pressure, energize the compressor.
7. Monitoring the gross weight of the refrigerant cylinder, weigh in the remaining refrigerant charge in liquid
state at P2, suction charging access port (up stream of accumulator).
IMPORTANT: Liquid refrigerant must always be charged upstream of the accumulator heat exchanger to
ensure the compressor is protected against liquid refrigerant.
3.4
FINAL OPERATING CHARGE
The refrigerant charge should be fine-tuned for the best operating efficiency of the cooling system. The exact
charge will vary depending on the evaporator size and refrigerant line length.
1. With the evaporator completely covered with milk/water or with the chilled solution circulating through the
chiller, operate the cooler or chiller with the startup refrigerant charge until the product is cooled below 45°F.
2. Check the evaporator superheat and ensure that it is properly adjusted. Milk cooler evaporator superheat
should be set at 4–6°F and chiller evaporator superheat should be set at 10–12°F. Refer to Section 5.0 for the
superheat adjustment.
3. Check the sight glass installed at the TEV inlet. If the sight glass shows vapor refrigerant (bubbles), go to step
4. If the sight glass is clear with liquid refrigerant, slowly recover refrigerant from the system at P6, high-side
service valve, until an occasional bubble of vapor is seen in the sight glass.
4. Slowly add refrigerant at P2, suction charging access port, until the sight glass becomes clear with liquid
refrigerant.
5. Check the superheat a second time to ensure the proper setting.
IMPORTANT: Liquid refrigerant must always be charged upstream of the accumulator heat exchanger,
access ports P2 or P3, to ensure the compressor is protected against liquid refrigerant slugging.
3.5 REFRIGERANT TESTING
When removing refrigerant from a system which has had a compressor failure, the refrigerant should be tested for
acid to ensure that it has not been contaminated by a burnout. If any contamination is found, recover the entire
refrigerant charge, replace the filter-drier, triple evacuate, and recharge with new or recycled refrigerant to meet
ARI 700-88 specifications.
3.6
SAFETY ALERT
Technicians should wear side-shielded safety glasses and butyl-lined gloves when handling refrigerants.
Liquid refrigerant will cause frostbite.
When refrigerants come in contact with an open flame or a high heat source, dangerous gases will form.
This is characterized by a strong acidic odor. Immediately vacate the area and ventilate prior to reentry.
7
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