Mueller E-Star OESE-A351-HFC User manual

Part No. 8828747
Effective April 13, 2020
E-Star® OESE
Condensing Unit
3.5 and 5 HP HFC
INSTALLATION AND OPERATION MANUAL

E-Star OESE Condensing Unit
3.5 and 5 HP HFC
INSTALLATION AND OPERATION MANUAL
Section 1.0 – Introduction
1.1 General Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Table 1: Dimensions and Weight ............................................................................................1
Figure 1: Dimensions and Weight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.2 Technical Support ......................................................................................................... 2
1.3 Installation Information ................................................................................................... 2
Section 2.0 – Installation
2.1 Inspection .................................................................................................................. 3
2.2 Handling .................................................................................................................... 3
2.3 Location..................................................................................................................... 3
2.4 Refrigeration Piping and Evacuation ..................................................................................... 3
Table 2: Liquid Line Sizing................................................................................................. 4
Table 3: Suction Line Sizing................................................................................................ 4
Table 4: Discharge Line Sizing To and From the Fre-Heater®........................................................... 4
Table 5: Condensing Unit Connection Sizes .............................................................................. 4
2.5 Electrical Connections .....................................................................................................5
2.6 Pump-Down Installations ..................................................................................................5
Section 3.0 – Refrigerant Charging
3.1 EPA Refrigerant Regulations .............................................................................................. 6
3.2 Initial Refrigerant Charge ................................................................................................. 6
Table 6: Recommended Startup Refrigeration Charge ................................................................... 6
3.3 Weigh-In Refrigerant Charging ........................................................................................... 6
3.4 Final Operating Charge .................................................................................................... 7
3.5 Refrigerant Testing ........................................................................................................ 7
3.6 Safety Alert ................................................................................................................. 7
Table of Contents
Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020

Section 4.0 – Operating Features
4.1 Refrigerant Cycle........................................................................................................... 8
4.2 Oil Return................................................................................................................... 8
4.3 Increased Operating Efficiency ........................................................................................... 8
Figure 2: Refrigerant Piping Schematics ................................................................................. 9
Section 5.0 – Expansion Valve
5.1 Thermal Expansion Valve (TEV) Selection and Installation...........................................................10
Table 7: Thermal Expansion Valve (TEV) Selection ....................................................................10
Figure 3: Thermal Expansion Valve (TEV) Installation ................................................................10
5.2 Checking and Adjusting Superheat ...................................................................................... 11
Figure 4: Checking and Adjusting Superheat ............................................................................ 11
Section 6.0 – Accumulator Heat Exchanger
6.1 Accumulator Heat Exchanger Functions ................................................................................12
Figure 5: Accumulator Heat Exchanger..................................................................................12
Section 7.0 – Electrical Schematics
7.1 OESE 5 HP, 460/60/3 Wiring Schematic (Effective After September 1, 2007)........................................13
7.2 OESE 5 HP, 460/60/3 Wiring Schematic (Effective Until August 31, 2007)...........................................14
7.3 OESE 3.5 and 5 HP, 200–220/50/1, 208–230/60/1 Wiring Schematic................................................. 15
7.4 OESE 3.5 and 5 HP, 200–240/50/3, 208–230/60/3 Wiring Schematic ................................................ 16
7.5 OESE Low-Voltage, 24-VAC Control Circuit ............................................................................ 17
7.6 OESE Control Circuit Retrofit, 24-VAC to 240-VAC, Pre-1996 Control Boxes ........................................18
Section 8.0 – Pressure Switches and Fan Control
8.1 Low-Pressure Switch with Automatic Reset ............................................................................ 19
8.2 High-Pressure Switch with Automatic Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.3 RGE Electronic Fan Speed Control.......................................................................................19
8.4 RGE Electronic Fan Pressure Control Setpoint Adjustment ...........................................................20
Figure 6: RGE Electronic Fan Pressure Control.........................................................................20
8.5 Off-Cycle Fan Pressure Switch...........................................................................................20
8.6 Schrader Core Identification .............................................................................................20
Section 9.0 – Equipment Sound Level
9.1 Sound Testing Equipment ................................................................................................21
9.2 Sound Measurement ......................................................................................................21
Figure 7: Sound Measurement ............................................................................................21
Table of Contents
Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020

Section 10.0 – Maintenance
10.1 E-Star OESE Refrigeration Survey.......................................................................................22
10.2 Maintenance Procedures .................................................................................................23
10.3 Safety Alert ................................................................................................................23
Section 11.0 – Disposal
11.1 General ....................................................................................................................24
11.2 Compressor Refrigerant Oil .............................................................................................24
11.3 Metal Components ........................................................................................................24
Section 12.0 – Equipment Markings
12.1 Label No. 8820454, Dry-Nitrogen Holding Charge......................................................................25
12.2 Label No. 8824716, HFC Refrigerant ....................................................................................25
12.3 Label No. 8824497, E-Star Data Plate....................................................................................25
12.4 Label No. 8822574, Inspection Card .....................................................................................25
12.5 Label No. 8820155, Wiring Connections for Three-Phase Scrolls .....................................................26
12.6 Label No. 8820156, Brief Power Interruptions on Scroll Single-Phase Compressors .................................26
12.7 Label No. 8822225, CE Data Tag (UK Models Only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
12.8 Label No. 31193, Screen Inside (Identifies Suction Line Screen Location) ............................................26
12.9 Label No. 8822232, Warning Symbol: Hot ...............................................................................27
12.10 Label No. 8820623, Warning Symbol: Electrical ........................................................................27
12.11 Label No. 8822226, Warning: Screen Guard Removal ..................................................................27
12.12 Label No. 8822141, Warning: Risk of Electric Shock, Disconnect All Remote Power Supplies Before Servicing ....27
12.13 Label No. 8820764, Warning: Disconnect Power Before Screen Guard Removal .....................................28
12.14 Label No. 8820768, Warning: Place Screen Guard Before Unit Operation .............................................28
12.15 Label No. 8820769, Warning: Fan Will Start Automatically ...........................................................28
12.16 Label No. 8824383, Mueller Logo.........................................................................................28
12.17 Label No. 8822705, CSA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Section 13.0 – Safety
13.1 Safety Alert ................................................................................................................29
13.2 Refrigerant Health Hazards ..............................................................................................29
13.3 First Aid ...................................................................................................................29
13.4 Personal Protective Equipment...........................................................................................29
Table of Contents
Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020

Section 14.0 – Technical Data
14.1 E-Star OESE Electrical Data .............................................................................................30
14.2 E-Star OESE Refrigerant Data ...........................................................................................30
14.3 E-Star OESE Compressor Oil Charge ....................................................................................30
Section 15.0 – Compressor Data Charts
15.1 ZB26KCE Single-Phase, 208/230 V Compressor Data Chart .......................................................... 31
15.2 ZB26KCE Three-Phase, 208/230 V Compressor Data Chart...........................................................32
15.3 ZB38KCE Single-Phase, 208/230 V Compressor Data Chart ..........................................................33
15.4 ZB38KCE Three-Phase, 208/230 V Compressor Data Chart...........................................................34
15.5 ZB38KCE Three-Phase, 460 V Compressor Data Chart ................................................................35
Section 16.0 – R-507 Pressure Temperature Chart ...............................................................36
Section 17.0 – E-Star OESE Installation Survey ...................................................................37
Table of Contents
Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
1.1 GENERAL SPECIFICATIONS
Mueller® E-Star OESE condensing units are engineered to maximize the energy efficiency and cooling capacity of
a milk cooling system. Custom and specialized components consist of the following:
1. A quiet, energy-efficient Copeland® “ZB” scroll refrigeration compressor, designed for commercial
refrigeration service rather than air conditioning, provides improved performance over the entire milk cooling
temperature range. An oil sight glass, oil fill/drain port, and screw electrical terminals are added bonuses that
ensure long-term reliability and serviceability.
2. An accumulator heat exchanger with a proprietary subcooling coil maximizes refrigeration capacity while
protecting the compressor from liquid refrigerant.
3. A custom tube-and-fin condenser with rifled tubing and integral subcooling loop provides an enhanced heat
exchange surface. The subcooling loop maintains subcooled liquid refrigerant to the thermal expansion valve,
ensuring maximum evaporator efficiency.
4. A single, variable speed, high-efficiency fan motor provides maximum condensing efficiency over a wide range
of ambient temperatures.
5. An electrical enclosure is designed for safety, ease of installation, and serviceability. A resistive heater is
included for reeliable operation during colder ambient temperatures.
6. The three-piece galvanized steel cover with an attached steel grill provides safe operation plus offers easy
service access.
7. Rust-resistant brass service valves are located for easy access without removing the cover.
TABLE 1: DIMENSIONS AND WEIGHT FIGURE 1: DIMENSIONS AND WEIGHT
1
Section 1.0 – Introduction
401⁄8˝
303⁄8˝
311⁄2˝
Width 101.92 cm 401⁄8in
Depth 77.15 cm 303⁄8in
Height 80.00 cm 311⁄2in
Approximate
Weight
5 HP 176 kg 388 lb
3.5 HP 162 kg 358 lb

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
1.2 TECHNICAL SUPPORT
This manual provides basic installation and operating information for Mueller E-Star OESE condensing units.
Please contact your local Paul Mueller Company Sales and Service Representative if you require additional
technical assistance pertaining to installation or operating procedures.
Manufacturer’s support is available by contacting the following:
Paul Mueller Company
Dairy Farm Equipment Service Department
1600 West Phelps Street
Springfield, Missouri 65802
Direct Telephone: [phone]
Facsimile: 1-800-436-2466
Email: [e-mail]
1.3 INSTALLATION INFORMATION
Electrical and refrigeration installation and service must be performed by an authorized service technician who
has the proper training to install and service refrigeration and electrical equipment.
Local, state, and/or country electrical and refrigeration regulations must be followed during installation, service,
and/or operation of this equipment.
United States Environmental Protection Agency (EPA) regulations require that any technician performing
refrigerant installation or service on a high-pressure appliance be certified as a Type II Technician in accordance
with Section 608 of the Clean Air Act. Clean Air Act regulations may change or differ, depending on locality. It is
the responsibility of the technician performing the refrigerant service and/or installation to abide by all regulatory
requirements and procedures for the locality, state, and country.
2

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
2.1 INSPECTION
Each shipment should be carefully checked for shortages or concealed damage. Any shortage or damage must be
reported to the delivery carrier at the time of delivery.
Damaged material becomes the delivery carrier’s responsibility and should not be returned to the manufacturer
unless prior approval is obtained.
2.2 HANDLING
IMPORTANT: Equipment used to move or lift this equipment must be rated for the weight of the
equipment. See Table 1 for equipment weight.
2.3 LOCATION
When choosing a location for the Mueller E-Star OESE condensing unit, consider these items:
• Environment: The unit must be located where it is protected from extreme temperatures of –30°F (–34.4°C)
and below or 115°F (46.1°C) and above.
• Condenser Air Flow: Ensure proper provisions for adequate air flow to the condenser. When installing the
condenser facing a wall, the distance to the wall must be a minimum of 18 in (45.72 cm) with non-restricted
air flow at the top, left, and right sides. Be especially cautious of installation methods that would allow the
condenser air flow to recirculate and conditions that would allow dust or oil to enter the condenser.
• Serviceability: The condensing unit should be located with the compressor and electrical enclosure
accessible for service. Do not pipe refrigerant lines in front of the electrical enclosure.
• Efficiency: Locate the condensing unit as close to the evaporator as possible. This will improve efficiency by
reducing pressure drop in the refrigerant piping.
• Lubrication: For proper oil return, do not install the condensing unit above the height of the evaporator, and
the suction line returning from the evaporator should be sloped towards the condensing unit.
2.4 REFRIGERATION PIPING AND EVACUATION
Refrigeration lines should be purged with dry nitrogen when brazing connections to prevent internal oxide
formation. Proper refrigerant practices as outlined in ASHRAE 15-1994 should be followed.
The refrigerant line set must be insulated to reduce heat gain, prevent sweating and condensation, and ensure
subcooled liquid refrigerant to the evaporator.
Refrigerant piping should be installed with long-radius bends or fittings.
E-Star OESE condensing units are shipped with a dry nitrogen holding charge. The unit, refrigerant lines, and
evaporator circuit will require a triple system evacuation to 500 microns prior to refrigerant charging. The system
must hold below 1,000 microns in a standing vacuum test, ensuring that it is leak free.
NOTE: Installation technicians must follow proper refrigerant practices as outlined in ASHRAE 15-1994.
3
Section 2.0 – Installation

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
TABLE 2: LIQUID LINE SIZING
Paul Mueller Company recommends the shortest pipe run possible.
TABLE 3: SUCTION LINE SIZING
Paul Mueller Company recommends the shortest pipe run possible.
TABLE 4: DISCHARGE LINE SIZING TO AND FROM THE FRE-HEATER®
Paul Mueller Company recommends the shortest pipe run possible.
TABLE 5: CONDENSING UNIT CONNECTION SIZES
4
Compressor
Horsepower
Equivalent Length of Pipe (Feet)
< 30ˇ 30ˇ – 50ˇ 50ˇ – 100ˇ
3.5 1⁄21⁄21⁄2
51⁄21⁄25⁄8
7.5 5⁄85⁄85⁄8
95⁄85⁄87⁄8
Compressor
Horsepower
Equivalent Length of Pipe (Feet)
< 30ˇ 30ˇ – 50ˇ 50ˇ – 100ˇ
3.5 7⁄811⁄811⁄8
5 11⁄811⁄813⁄8
7.5 11⁄813⁄815⁄8
9 13⁄815⁄821⁄8
Compressor
Horsepower
Equivalent Length
of Pipe (Feet)
0ˇ – 50ˇ
3.5 7⁄8
57⁄8
7.5 11⁄8
9 11⁄8
Compressor
Horsepower Liquid Line Suction Line
Discharge Line
(Fre-Heater®)
3.5 1⁄27⁄81⁄2
55⁄87⁄81⁄2
7.5 5⁄815⁄811⁄8
95⁄815⁄811⁄8

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
2.5 ELECTRICAL CONNECTIONS
Prior to installation, verify equipment is compatible with site electrical requirements (e.g., voltage, phase, and
hertz). Ensure that all electrical connections are secure and correspond with wiring schematics.
Following local and National Electrical Code (NEC) regulations and procedures, connect a fused-disconnect power
supply of the proper voltage and phase to the condensing unit’s electrical enclosure.
The control circuit is designed to be operated by a 24-VAC supply. See warning statement below.
Refer to the electrical schematics in Section 7 for connection details.
WARNING: Mueller E-Star OESE condensing units are prewired for low-voltage, 24-VAC control
circuit input. Connecting high-voltage control to this circuit will cause equipment failure and a possible
electrical hazard.
The control circuit can be modified for high-voltage supply in installations that do not utilize a Mueller low-voltage
refrigeration control. Refer to Section 7.0 for details.
2.6 PUMP-DOWN INSTALLATIONS
An optional hard start kit is available for single-phase models utilizing a refrigerant pump-down solenoid. refer to
Section 7.0 for details and part numbers.
A discharge check valve, Part No. 8820260 for 5-HP models and 8820255 for 3.5-HP models, must be installed in
the compressor’s discharge line for pump-down installations.
5

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
3.1 EPA REFRIGERANT REGULATIONS1
Mueller E-Star OESE condensing units are designed to operate with R-507 refrigerant. R-507 is specified by the
ASHRAE Standard 34 Safety Classification as an A-1 refrigerant with low-flame propagation and low toxicity.
EPA regulations require that any technician performing refrigerant installation or service on a high-pressure
appliance be certified as a Type II Technician in accordance with Section 608 of the Clean Air Act.
1 As adopted for the United States and Canada. These regulations may change or dier for your locality. It is the responsibility of the
technician performing the refrigerant service and/or installation to abide by all regulatory requirements for the installation locality,
state, and country.
3.2 INITIAL REFRIGERANT CHARGE
IMPORTANT: E-Star OESE condensing units must be triple evacuated to 500 microns before refrigerant
charging.
The most efficient and reliable method to charge the condensing unit is to weigh in the charge, ensuring it matches
the startup charge recommendations in Table 6. Section 3.3 outlines the weigh-in procedure.
IMPORTANT: The recommended startup charge is only an initial charge; more refrigerant may be
necessary to have a properly charged system. Refer to Section 3.3 for final charge information.
TABLE 6: RECOMMENDED STARTUP REFRIGERANT CHARGE
NOTE: R-507 is recommended for use with E-Star OESE condensing units. Other refrigerants may be compatible;
contact Paul Mueller Company’s Dairy Farm Equipment Service Department for more information.
3.3 WEIGH-IN REFRIGERANT CHARGING
The following steps outline the procedure to weigh in the refrigerant startup charge. Refer to the refrigerant piping
schematic shown in Figure 2.
1. With a clean, evacuated system, connect the manifold gauges to the suction service valve (P2) and the high-
side service valve (P6).
2. Connect the center charging hose to a cylinder of new or reclaimed ARI 700-88 specifications refrigerant.
3. Weigh and record the gross weight of the refrigerant cylinder.
4. Purge any air from the manifold gauge hoses, as specified by EPA Section 608, de-minimus release.
5. Break the refrigeration system’s vacuum with liquid refrigerant, charging into the Schrader port at the suction
service valve (P2).
6
Section 3.0 – Refrigerant Charging
Condensing Unit Size
Recommended Startup Charge
Milk Cooler Chiller
3.5 HP 13.5 lbs / 6.12 kg 11.5 lbs / 5.22 kg
5 HP 15 lbs / 6.8 kg 13 lbs / 5.9 kg

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
3.3 WEIGH-IN REFRIGERANT CHARGING (CONTINUED)
6. When the system pressure equalizes with cylinder pressure, energize the compressor.
7. Monitoring the weight of the refrigerant cylinder, weigh in the remaining refrigerant charge, in liquid state, at
the suction service valve (P2).
IMPORTANT: Liquid refrigerant must always be charged upstream of the accumulator heat exchanger, to
ensure the compressor is protected from liquid refrigerant slugging.
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 the refrigerant line length.
1. With the milk cooler’s evaporator covered with milk/water or the chilled solution circulating through
the chiller, operate the cooler or chiller with the startup refrigerant charge until the product is cooled to a
temperature below 45°F (7.2°C).
2. Check the evaporator’s superheat, ensuring it is properly adjusted. The milk coolor’s evaporator superheat
should be set at 4–6°F (2.2–3.3°C), and the chiller’s evaporator superheat should be set at 10–12°F (5.6–6.7°C).
Refer to Section 5.0 for 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 the high-side
service valve (P6), until an occasional bubble of vapor is seen in the sight glass.
4. Slowly add refrigerant at suction service valve (P2), 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 port P2, to ensure the compressor is protected against liquid refrigerant slugging.
3.6 REFRIGERANT TESTING
When removing refrigerant from a system that 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.
3.7 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
!

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
4.1 REFRIGERANT CYCLE
Mueller E-Star OESE condensing units utilize an thermal expansion valve (TEV) that controls the evaporator’s
superheat. The expansion valve must be field adjusted to maintain the milk coolor’s evaporator’s superheat at
4–6°F (2.2–3.3°C) or the chiller’s superheat at 10–12°F (5.6–6.7°C).
Refer to Figure 2, “Refrigeration Piping Schematic.” Subcooled liquid refrigerant leaves the condenser coil and
flows through the heat exchanger coil in the accumulator, where it is subcooled an additional 5–15°F (2.7–8.5°C).
This heat exchange also evaporates any liquid refrigerant in the suction accumulator, protecting the compressor
against liquid flood-back.
As the liquid refrigerant, now subcooled a total of 10–25°F (5.6–13.9°C), passes through the expansion valve, its
pressure is reduced to an evaporative pressure. Since the liquid refrigerant was subcooled in the accumulator
heat exchanger coil before entering the evaporator, there will be less flash gas at the inlet of the expansion valve.
Any liquid refrigerant returned from the evaporator is evaporated into vapor when it contacts the warmer heat
exchanger coil in the bottom of the suction accumulator. Vapor leaving the accumulator heat exchanger will be
superheated an additional 2–5°F (1.1–2.8°C) prior to entering the compressor’s suction intake. This minimal
superheat provides protection against liquid refrigerant entering the compressor, while providing exceptional
refrigerant cooling of the compressor.
4.2 OIL RETURN
Refrigerant oil returning from the evaporator drops into the accumulator where the oil separates from the
refrigerant and settles to the bottom of the accumulaotr. This oil is metered back into the compressor through
the oil pickup orifice, located in the bottom of the accumulator’s suction outlet “J” tube. Refer to Section 6.0,
“Accumulator Heat Exchanger.”
4.3 INCREASED OPERATING EFFICIENCY
Mueller E-Star OESE condensing units incorporate a receiver and condenser subcooling loop to maintain proper
subcooled liquid refrigerant to the TEV, which ensures optimum evaporator efficiency.
8
Section 4.0 – Operating Features

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
FIGURE 2: REFRIGERANT PIPING SCHEMATICS
IMPORTANT: When charging the system with liquid refrigerant, always charge upstream of the
accumulator heat exchanger (access ports P2) to ensure the compressor is protected against damage
caused by liquid refrigerant slugging.
9
Subcooling Loop
Fan
Scroll Compressor
Ambient Air
Receiver
This is a custom-designed
accumulator heat exchanger.
To ensure proper system
operation, a genuine Mueller
accumulator heat exchanger
must be used.
Accumulator
Heat Exchanger
Fan
ControlFP
(O-Cycle)
HP
LP
T1: Product Temperature
Liquid Refrigerant
Liquid-Vapor Refrigerant
Vapor Refrigerant
T2
P3
P4
P2
P6
T4 T6
T3
T5
P5
P1
DFE0117
60 psig
40°F T7
Example (R-507):
• 60 psig converted to saturation temperature on
refrigerant pressure temperature table equals 34°F.
• Actual suction line temperature equals 40°F.
Results:
• 40°F – 34°F = 6°F (4.4°C – 1.1°C = 3.3°C)
superheat at evaporator.

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
5.1 THERMAL EXPANSION VALVE (TEV) SELECTION AND INSTALLATION
The E-Star’s TEV must be field adjusted to maintain milk cooler evaporator superheat at 4–6°F or chiller
evaporator superheat at 10–12°F. Proper location and sizing of the thermal expansion valve is critical. Refer to
Section 5.2 for the superheat adjustment procedure.
An externally equalized TEV must be used on Mueller milk cooling applications. A sight glass must be installed at
the TEV inlet.
TABLE 7: THERMAL EXPANSION VALVE (TEV) SELECTION
FIGURE 3: THERMAL EXPANSION VALVE (TEV) INSTALLATION
10
Section 5.0 – Expansion Valve
No. Description Specifications
Part No. for Milk
Cooler Applications
Part No. for
Chiller Applications
1A R-22 (5 HP) 1⁄2" ODF inlet x 5⁄8" ODF outlet solder 8824492 8824511
1B R-22 (3.5 HP) 1⁄2" ODF inlet x 5⁄8" ODF outlet solder 8824490 N/A
1C R-507 (5 HP) 1⁄2" ODF inlet x 5⁄8" ODF outlet solder 8825503 9843711
1D R-507 (3.5 HP) 1⁄2" ODF inlet x 5⁄8" ODF outlet solder 8825505 N/A
1E R-404a (5 HP) 1⁄2" ODF inlet x 5⁄8" ODF outlet solder 9844469 N/A
1F R-404a (3.5 HP) 1⁄2" ODF inlet x 5⁄8" ODF outlet solder 9844468 N/A
2 Sight Glass, All 1⁄2" ODF x 1⁄2" ODM solder 8824494 8824494
The TEV sensing bulb should be located
a minimum of 10 tube diameters away
from any fittings or bends.
Example: 7/8" suction line (x) 10 = 83/4".
Securely mount and insulate the TEV sensing
bulb at a 4-o’clock position on the copper
suction line. Horizontal mounting is always
recommended when possible. If vertical
mounting is required, maintain the minimum
dimensions as stated above.
4 o'clock
12 o'clock
1
2

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
5.2 CHECKING AND ADJUSTING SUPERHEAT
Take the following readings with the cooler’s evaporator completely covered with milk or water, or with the chilled
water solution circulating through the chiller, at a temperature below 45°F.
1. Take an accurate suction pressure at the evaporator outlet.
IMPORTANT: The suction pressure must be taken at the evaporator outlet, rather than the suction
service valve, due to the unknown pressure drop in the refrigerant line between the evaporator and
compressor. The technician should also make certain the system is properly charged with refrigerant as
described in Section 3.
2. Using an accurate electronic thermometer, take the actual suction line temperature near the TEV sensing bulb.
3. Utilizing the pressure temperature chart, convert the suction pressure reading from step 1 to the saturation
temperature (dew point).
4. The superheat value is calculated by subtracting the saturation temperature (dew point) determined in step 3
from the actual suction line temperature taken in step 2.
5. If the superheat is not in the proper range, 4–6°F (2.2–3.3°C) for milk coolers and 10–12°F (5.6–6.7°C) for
chillers, at conditions as described above, adjust the TEV.
6. If the superheat is below the proper range, turn the TEV’s adjustment stem clockwise 1⁄8to 1⁄4of a turn. Allow
the system to operate for five minutes before repeating the test.
7. If superheat is above the proper range, turn the TEV’s adjustment stem counterclockwise 1⁄8to 1⁄4of a turn.
Allow the system to operate for five minutes before repeating the test.
8. Any time adjustment is made to the TEV, the refrigerant charge should be checked as described in Section 3.0.
9. Check the superheat setting and make final adjustments at a product temperature near setpoint for best
performance.
FIGURE 4: CHECKING AND ADJUSTING SUPERHEAT
11
40°F
60 PSIG
Example (R-507):
• 60 psig converted to saturation temperature on
refrigerant pressure temperature table equals 34°F.
• Actual suction line temperature equals 40°F.
Results:
• 40°F – 34°F = 6°F (4.4°C – 1.1°C = 3.3°C)
superheat at evaporator.

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
6.1 ACCUMULATOR HEAT EXCHANGER FUNCTIONS
The accumulator heat exchanger performs several functions on the E-Star OESE condensing unit:
• Additional Subcooling: The high-pressure liquid refrigerant from the condenser is subcooled 5–15°F (2.7–
8.5°C) as it passes through the heat exchanger coil in the bottom of the accumulator heat exchanger, which is
submerged in cold liquid refrigerant that has returned from the evaporator.
• Vapor Return to the Compressor: The accumulator heat exchanger evaporates accumulated liquid
returning from the evaporator, providing cool vapor refrigerant to the suction inlet of the compressor.
• Oil Return to the Compressor: Oil settles to the bottom of the accumulator and is returned to the
compressor through an orifice in the accumulator’s suction outlet.
IMPORTANT: The Mueller accumulator heat exchanger utilizes a special “pancake” heat exchange
coil. The use of a generic (spiral) accumulator heat exchanger will severely reduce cooling capacity of
the E-Star OESE condensing unit and may cause premature compressor failure. Use genuine Mueller
replacement parts only.
FIGURE 9: ACCUMULATOR HEAT EXCHANGER
12
Section 6.0 – Accumulator Heat Exchanger
Suction Outlet
Oil Return Orifice
Heat Exchanger
Liquid Inlet
Suction Inlet
Liquid Outlet
The bae in the suction inlet
directs the refrigerant to the
outer wall of the accumulator.

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
7.1 OESE 5 HP, 460/60/3 WIRING SCHEMATIC (EFFECTIVE AFTER SEPTEMBER 1, 2007)
13
Section 7.0 – Electrical Schematics
CONDENSING UNIT WIRING SCHEMATI
C
FOR CONTROL CABINETS UTILIZIN
G
24-VOLT CONTROL OU
TPUT
DFE021
2
NO
TES:
1.
CAUTION: The side of the control circuit employing
the safety device shall not be grounded.
2.
Minimal 20 VA transformer required for control voltage.
3.
Use minimum of 75°C insulated copper wire on field wiring.
4.
Fan motor is internally thermal protected.
5.
Connect 24-volt control wiring to leads with supplied wire nuts.
6.
Field wiring not to come in contact with control box heater.
7.
All enforced electrical codes must be followed during installation, service, and/or operation of this equipment.
8.
All grounds terminate in the control box except the crankcase heater which terminates next to the compressor on the base plate.

Mueller E-Star OESE 3.5 and 5 HP HFC Condensing Unit
Installation and Operation Manual, Part No. 8828747 Effective April 13, 2020
14
7.2 OESE 5 HP, 460/60/3 WIRING SCHEMATIC (EFFECTIVE UNTIL AUGUST 31, 2007)
NO
TES:
1.
CAUTION: The side of the control
circuit employing the safety device
shall not be grounded.
2.
Minimal 20 VA transformer
required for control voltage.
3.
Use minimum of 75°C insulated
c
opper wire on field wiring.
4.
Fan motor is internally thermal protected.
5.
Connect 24-volt control wiring to
leads with supplied wire nuts.
6.
Field wiring not to come in contact with control box heater.
7.
All enforced electrical codes must be followed during
installation, service, and/or operation of this equipment. DFE0155
3
2
3
1
1
2
3
4
TO CUSTOMER SUPPLIED
FUSED DISCONNECT
208–230/60/1
FAN SPEED
CONTROL
FV31-S2-15S
EFFECTIVE TO
SEPTEMBER 2002
FAN SPEED
CONTROL
FV31-S2-25S
EFFECTIVE TO
JANUARY 2002
BLACK
YELLOW
RED
FAN
CAPACITOR
BROWN
BROWN
BLUE
FAN MOTOR
BLACK
OFF-CYCLE
FAN SWITCH
FAN SPEED
CONTROL
CURRENT
HIGH PRESSURE
SWITCH
LOW PRESSURE
SWITCH
TERMINAL
BLOCK
240V
34L2 L2 L1L1
BLUE
BLUE
BLACK
CRANKCASE HEATER
BLACK
BLUE
BLUE
SEE NOTE #2
24 V CONTROL
FROM
CONTROL BOX
SEE NOTE #5
BLUE
BLUE
BLUE
BLUE
BLACK
BLACK
TERMINAL
BLOCK
24V
1234
COMPRESSOR
CONTROL BOX HEATER
BLACK
YELLOW
RED
TAN/RED STRIPE
TAN/RED STRIPE
T1
T2
T3
24V COIL
BLUE
BLUE
T1
L1
T2
L2
T3
L3
A
B
BLUE
BLUE
24V COIL
1
0
8
4
6
2
RELAY
SWITCH
GROUND
CUSTOMER-SUPPLIED
FUSED DISCONNECT
380–420/50/3 or
460/50/3 or 460/60/3
GROUND
GROUND
GROUND
CONDENSING UNIT WIRING SCHEMATI
C
FOR CONTROL CABINETS UTILIZIN
G
24-VOLT CONTROL OU
TPUT