Description
The unit is designed so that the majority of the components are accessible from the front, see Figure 3.1. The unit model number, serial number and parts identification number can be found on the unit nameplate located next to the compressor.
Figure 3.1 Container Unit - Front View
1)Evaporator Section Access Panel(s)
2)Fresh Air Makeup Vent
3)Fork Lift Pockets
4)Condenser
5)Control Box with Unit Display and Keypad
6)Start-Stop Switch
7)Power Cables and Plug
8)Compressor
9)Unit Nameplate, see Figure 2.2
10)Unit Options Label
- - - - -
The container unit components, as shown in Figure 3.2, can be separated into four sections:
1.Compressor section
2.Condenser section
3.Evaporator section
4.Control box section
Figure 3.2 Container Unit Sections
The compressor receives refrigerant vapor from the evaporator and compresses it to a high pressure, high temperature gas before directing it to the condenser.
The compressor section includes a compressor, service valves (discharge and suction), pressure transducers (discharge, suction, evaporator), a high pressure switch, a discharge temperature sensor, a digital unloader valve and an economizer.
NOTE: PrimeLINE EDGE units (571-3xx models) also include a digital loader valve.
Compressor section components for standard units (571-1xx models) are shown in Figure 3.3.
Compressor section components for EDGE units (571-3xx models) are shown in Figure 3.4.
The air-cooled condenser removes latent heat from the refrigerant gas by using a condenser fan to blow air across the condenser coil fins and tubes to cool the gas to saturation temperature. The condenser fan pulls air from around the coil and discharges it horizontally through the condenser fan grille.
The condenser section includes a condenser fan, condenser coil, receiver, liquid line service valve, and a filter drier.
Condenser section components for standard units (571-1xx models) are shown in Figure 3.3.
Condenser section components for EDGE units (571-3xx models) are shown in Figure 3.4.
The evaporator fans circulate air through the container by pulling it from the top of the unit, through the evaporator coil to be heated or cooled, and discharging it at the bottom of the refrigeration unit into the container.
The evaporator section includes two evaporator fans, an evaporator coil, heaters, defrost temperature sensor, heat termination thermostat, electronic expansion valve, evaporator temperature sensor and (optional) humidity sensor.
Evaporator section components are shown in Figure 3.5.
NOTE: This section is the same for standard units (571-1xx models) and EDGE units (571-3xx models).
The control box section includes the display module and keypad on the control box door and the start/stop switch mounted to the right of the door. Inside the door are the unit controller (control module), controller battery pack, circuit breaker (CB1), contactors for the compressor, fans and heater, fuses, control power transformer, transformer AC line filter and the current sensor module.
The unit controller, display module and keypad are described in the Microprocessor chapter, see Section 4.1.
Control box section components for standard units (571-1xx models) are shown in Figure 3.6.
Control box section components for EDGE units (571-3xx models) are shown in Figure 3.7.
Figure 3.3 Compressor and Condenser Section - Standard Units (571-1xx models)
1)Compressor, R-513A ready
Note: Discharge Temperature Sensor (CPDS) not shown, mounted on back of compressor
2)Compressor Terminal Box
3)Discharge Connection
4)Discharge Service Valve
5)High Pressure Switch (HPS)
6)Discharge Pressure Transducer (DPT)
7)Condenser Coil, MCHE
8)Condenser Fan and Motor, Single Speed
9)Receiver
10)Filter Drier
11)Liquid Line Service Valve (King Valve)
12)Economizer
13)Economizer Solenoid Valve (ESV)
14)Economizer Expansion Valve (EXV)
15)Economizer Connection to Compressor
16)Tubing, Economizer to Evaporator
17)Tubing, Evaporator to Compressor
18)Evaporator Pressure Transducer (EPT)
19)Suction Pressure Transducer (SPT)
20)Digital Unloader Valve (DUV)
21)DUV Connection
22)Suction Service Valve
23)Suction Connection
24)Supply Temperature Sensor (STS) / Supply Recorder Sensor (SRS)
25)Ambient Temperature Sensor (AMBS)
- - - - -
Figure 3.4 Compressor and Condenser Section - EDGE Units (571-3xx models)
1)Compressor, R-513A ready
Note: Discharge Temperature Sensor (CPDS) not shown, mounted on back of compressor
2)Compressor Terminal Box
3)Discharge Connection
4)Discharge Service Valve
5)High Pressure Switch (HPS)
7)Discharge Pressure Transducer (DPT)
8)Condenser Coil, MCHE
9)Condenser Fan and Motor, Dual Speed
10)Receiver
11)Filter Drier
12)Liquid Line Service Valve (King Valve)
13)Economizer
14)Economizer Solenoid Valve (ESV)
15)Economizer Expansion Valve (EXV)
16)Economizer Connection to Compressor
17)Tubing, Economizer to Evaporator
18)Tubing, Evaporator to Compressor
19)Evaporator Pressure Transducer (EPT)
20)Suction Pressure Transducer (SPT)
21)Digital Unloader Valve (DUV)
22)DLV / DUV Connection
23)Suction Service Valve
24)Suction Connection
25)Supply Air Temperature Sensors (STS) / (SRS)
26)Ambient Temperature Sensor (AMBS)
- - - - -
NOTE: The PrimeLINE EDGE unit (571-3xx models) layout shown above is the same as a PrimeLINE standard unit (571-1xx models) with a few differences:
•Item 6, 22: A digital loader valve is included to allow for compressor optimization.
•Item 9: A dual speed condenser motor is utilized to enable low speed operation under light load.
Figure 3.5 Evaporator Section
1)Evaporator Fan and Motor (EM1, EM2)
2)Return Temperature Sensor (RTS) / Return Recorder Sensor (RRS)
3)Humidity Sensor (HS), if installed**
4)Electronic Expansion Valve (EEV)
5)Evaporator Temperature Sensor (ETS1 / ETS2)
6)Evaporator Coil
7)Heaters (6)
8)Defrost Drain
9)Heat Termination Thermostat (HTT)**
10)Defrost Temperature Sensor (DTS)**
11)Vent Position Sensor (VPS), if installed**
- - - - -
** general location, not shown in figure.
Figure 3.6 Control Box Section - Standard Units (571-1xx models)
1)Controller
2)Controller Battery Pack and Battery
Note: Located above controller (not shown)
3)Start-Stop Switch (ST)
4)Compressor Contactor (CH)
5)Compressor Phase A Contactor (PA)
6)Compressor Phase B Contactor (PB)
7)Heater Contactor (HR)
8)Evaporator Fan Contactor High Speed (EF)
9)Evaporator Fan Contactor Low Speed (ES)
10)Condenser Fan Contactor (CF)
11)Current Sensor Module
12)Circuit Breaker (CB1) 460V
13)Control Transformer
14)Transformer AC Line Filter
- - - - -
Figure 3.7 Control Box Section - EDGE Units (571-3xx models)
1)Controller
2)Controller Battery Pack and Battery
Note: Located above controller (not shown)
3)Start-Stop Switch (ST)
4)Compressor Contactor (CH)
5)Compressor Phase A Contactor (PA)
6)Compressor Phase B Contactor (PB)
7)Heater Contactor (HR)
8)Evaporator Fan Contactor High Speed (EF)
9)Evaporator Fan Contactor Low Speed (ES)
10)Condenser Fan Contactor High Speed (CF)
11)Condenser Fan Contactor Low Speed (CL)
12)Current Sensor Module
13)Circuit Breaker (CB1) 460V
14)Control Transformer
15)Transformer AC Line Filter
- - - - -
NOTE: The PrimeLINE EDGE unit (571-3xx models) control box layout above is the same as a standard PrimeLINE unit (571-1xx models) with the exception of items 10 and 11: two contactors for the condenser fan (CF, CL).
3.3Main Component Descriptions
3.3.1Compressor
The compressor, shown in Figure 3.8, receives refrigerant vapor from the evaporator and compresses it to a high pressure, high temperature gas before directing it to the condenser. The compressor contains a terminal box, oil drain, refrigerant discharge and suction connections.
Figure 3.8 Compressor
From the compressor, the refrigerant flows to the air-cooled condenser, shown in Figure 3.9. The condenser fan blows the air across the coil fins and tubes to cool the gas to saturation temperature. By removing latent heat, the gas condenses to a high pressure / high temperature liquid and flows to the receiver.
NOTE: Standard units (571-1xx models) use a single speed condenser fan while EDGE units (571-3xx models) use a dual speed fan to enable low speed operation under light load.
Figure 3.9 Condenser Coil and Fan
3.3.3Water-Cooled Condenser Option
The unit may contain an optional brazed plate water-cooled condenser (WCC), shown in Figure 3.10, located to the left of the economizer. The WCC contains water in and water out couplings and a water pressure switch. When operating on the WCC, the condenser fan is deactivated by the water pressure switch. The receiver is retained in this configuration and the WCC is placed between the air-cooled condenser and the receiver.
Figure 3.10 Brazed Plate Water-Cooled Condenser
The receiver, shown in Figure 3.11, receives high pressure / high temperature liquid refrigerant from the condenser and stores it for when it is needed during low temperature operation. The receiver contains a sight glass, moisture indicator and fusible plug.
NOTE: Units with PID number NT30xx (and NT3115), are shipped with a steel receiver. Units with PID number NT31xx and higher are shipped with an aluminum receiver.
Figure 3.11 Receiver (Aluminum)
Refrigerant flows from the receiver through the filter drier, shown in Figure 3.12, which removes particulates and small amounts of water from the refrigerant to keep it clean and dry.
Figure 3.12 Filter Drier
The economizer, shown in Figure 3.13, receives refrigerant from the filter drier. The economizer unit includes an economizer solenoid valve (ESV) and economizer expansion valve (EXV), as explained in Section 3.5.4.
The economizer is only active when the unit enables economized mode and the controller energizes the ESV. The liquid refrigerant flows through the ESV to the EXV internal passages, absorbing heat from the liquid refrigerant flowing to the electronic expansion valve (EEV). The resultant “medium” temperature/pressure gas is directed back to the compressor. An EXV bulb senses refrigerant temperature and will regulate the opening of the EXV to prevent liquid from returning to the compressor.
If economized mode is not active, the economizer is bypassed and refrigerant flows directly to the EEV.
NOTE: The EEV position (%) reading can be viewed on the unit display at function code Cd54.
Figure 3.13 Economizer
Refrigerant enters the evaporator coil, shown in Figure 3.14, as a low pressure, low temperature saturated mixture and exits as a vapor. As the refrigerant enters the coil, two dual speed evaporator fans blow air on the coil. Heat is absorbed from the air by the balance of the liquid, causing it to vaporize in the coil. And the cooler air is returned to the container unit.
Figure 3.14 Evaporator Coil and Fans
The heaters, shown in Figure 3.15, are energized when Heating mode or Defrost mode is called for by the controller.
Figure 3.15 Heaters
3.3.9Heat Termination Thermostat
The heat termination thermostat (HTT), shown in Figure 3.16, is a safety device attached to an evaporator coil circuit that opens the heating circuit if overheating occurs.
Figure 3.16 Heat Termination Thermostat (HTT)
3.3.10Evaporator Access Panels and Air Makeup Vent
Most evaporator components are accessible by removing the upper back rear panel, inside the container unit. They may also be accessed via the evaporator fan access panels on the front of the unit, as shown in Figure 3.17.
The left access panel contains the fresh air makeup vent, which is a manually operated venting system that provides ventilation for commodities that require fresh air circulation. The fresh air makeup vent may be equipped with an optional vent position sensor (VPS) that determines the vent position.
Refer to Section 5.3 for the procedure to adjust the fresh air makeup vent.
If a VPS is installed, the fresh air vent position can be viewed on the unit display at function code Cd45.
Figure 3.17 Access Panels and Fresh Air Makeup Vent
3.4Service Valves Descriptions
3.4.1Compressor Service Valves
There are two compressor service valves (discharge and suction), shown in Figure 3.18, that allow connecting of the manifold gauge set to perform refrigerant service. The service valves are provided with a double seat and an access valve which enables servicing of the compressor and refrigerant lines.
Figure 3.18 Compressor Service Valves
3.4.2Liquid Line Service Valve
The liquid line service valve, shown in Figure 3.19, is for service procedures related to adding and removing refrigerant and also to assist with pumping refrigerant to the high side of the unit to allow service of specific components. This is also referred to as the king valve.
Figure 3.19 Liquid Line / King Valve
3.5Refrigerant Valves Descriptions
The normally closed digital unloader valve (DUV), shown in Figure 3.20, in the standard mode of operation, controls the system refrigerant flow and capacity by loading and unloading the compressor in frequent discrete time intervals.
NOTE: The DUV reading (% closed) can be viewed on the unit display at function code Cd01.
NOTE: The DUV open/closed status can be viewed on the unit display at function code Cd15.
Figure 3.20 Digital Unloader Valve (DUV)
The digital loader valve (DLV), shown in Figure 3.21, is a unique component to PrimeLINE EDGE units (571-3xx models). The normally closed valves DLV and DUV, in the standard mode of operation, control the system refrigerant flow and capacity by loading and unloading the compressor in frequent discrete time intervals. The DLV and DUV operate in opposition to each other such that when the DLV is closed the DUV is open and vice versa.
NOTE: The DLV open/closed status can be viewed on the unit display at function code Cd15.
Figure 3.21 Digital Loader Valve (DLV)
3.5.3Electronic Expansion Valve
The electronic expansion valve (EEV), shown in Figure 3.22, drops the pressure of the liquid refrigerant to suction pressure. As this happens, some of the liquid vaporizes to a gas (flash gas), removing heat from the remaining liquid. The liquid is then sent to the evaporator as a low pressure, low temperature, saturated mix.
NOTE: The EEV position (%) can be viewed on the unit display at function code Cd54.
Figure 3.22 Electronic Expansion Valve (EEV)
3.5.4Economizer Valves
The economizer solenoid valve (ESV) and economizer expansion valve (EXV) are shown in Figure 3.23.
The controller energizes the ESV during Economized mode. The liquid refrigerant flows through the ESV to the EXV internal passages, absorbing heat from the liquid refrigerant flowing to the electronic expansion valve (EEV). The resultant “medium” temperature / pressure gas is directed back to the compressor.
Figure 3.23 Economizer Valves
3.6Refrigerant Probes Descriptions
3.6.1Compressor Discharge Temperature Sensor
The compressor discharge temperature sensor (CPDS), shown in Figure 3.24, measures the temperature of the refrigerant as it is discharged from the compressor.
NOTE: The CPDS reading can be viewed on the unit display at function code Cd11.
Figure 3.24 Compressor Discharge Temperature Sensor (CPDS)
The high pressure switch (HPS), shown in Figure 3.25, monitors abnormally high discharge pressure. It opens at 25 (+/- 1.0) kg/cm2 | 350 (+/- 10) psig.
Figure 3.25 High Pressure Switch (HPS)
3.6.3Discharge Pressure Transducer
The discharge pressure transducer (DPT), shown in Figure 3.26, monitors refrigerant pressure on the discharge side of the compressor. The DPT is located behind the receiver.
NOTE: The DPT reading can be viewed on the unit display at function code Cd14.
Figure 3.26 Discharge Pressure Transducer (DPT)
3.6.4Evaporator / Suction Pressure Transducer
The evaporator pressure transducer (EPT) and suction pressure transducer (SPT), shown in Figure 3.27, monitors refrigerant on the suction side of the compressor.
NOTE: The EPT and SPT readings can be viewed on the unit display at function code Cd12.
Figure 3.27 Evaporator Pressure Transducers - EPT (top) and SPT (bottom)
3.6.5Evaporator Temperature Sensor
The evaporator temperature sensor (ETS1/2), shown in Figure 3.28, records the temperature of the refrigerant leaving the evaporator. It is located to the side of the evaporator coil.
NOTE: The ETS reading can be viewed on the unit display at function code Cd10.
Figure 3.28 Evaporator Temperature Sensor (ETS1/2)
3.7Air Stream Sensors Descriptions
3.7.1Supply Temperature Sensors
The supply temperature sensor (STS) and supply recorder sensor (SRS) are shown in Figure 3.29. The STS monitors the supply air temperature as it enters the container unit near the unit floor. The controller maintains the supply air temperature at setpoint during Perishable mode according to the STS. The SRS is for recording temperature and also to backup the STS in case of failure. See Section 4.3.2 for details on Perishable mode.
NOTE: The SRS reading can be viewed on the unit display at function code dC1.
Figure 3.29 Supply Temperature Sensor (STS) / Supply Recorder Sensor (SRS)
3.7.2Return Temperature Sensors
The return temperature sensor (RTS) and return recorder sensor (RRS) are shown in Figure 3.30. The RTS monitors the return air temperature at the top of the container unit above the evaporator fans. The controller maintains the return air temperature at setpoint during frozen mode according to the RTS. The RRS is for recording temperature and also to backup the RTS in case of failure. See Section 4.3.4 for details on frozen mode.
NOTE: The RRS reading can be viewed on the unit display at function code dC2.
Figure 3.30 Return Temperature Sensor (RTS) / Return Recorder Sensor (RRS)
3.7.3Ambient Temperature Sensor
The ambient temperature sensor (AMBS), shown in Figure 3.31, measures ambient temperature that the controller monitors to adjust operating modes accordingly inside the unit. It is located next to the economizer.
NOTE: The DTS reading can be viewed on the unit display at function code Cd09.
Figure 3.31 Ambient Temperature Sensor (AMBS)
3.7.4Defrost Temperature Sensor
The defrost temperature sensor (DTS), shown in Figure 3.32, determines the initiation of Defrost mode. When the DTS senses a temperature less than 10°C (50°F), the defrost options become active and the timer is engaged for the initiation of the defrost cycle. See Section 4.3.6 for more information on defrost mode.
NOTE: The DTS reading can be viewed on the unit display at function code Cd26.
Figure 3.32 Defrost Temperature Sensor (DTS)
The humidity sensor (HS), shown in Figure 3.33, is an optional component that detects the relative humidity inside the container unit.
NOTE: The HS reading of relative humidity (%) can be viewed on the unit display at function code Cd17.
NOTE: The humidity settings are controlled on the unit display at function code Cd33.
Figure 3.33 Humidity Sensor (HS)
3.7.6USDA Probes and Cargo Probe
If equipped, the unit has the capability of recording three USDA probes (USDA 1-3) and one cargo probe. The 3-pin receptacles for plugging in the probes are located in the evaporator section. The probe leads are plugged into the desired receptacle, shown in Figure 3.34. There is also a 5-pin interrogator receptacle (ICR) for third party device connectivity.
NOTE: USDA probe readings can be viewed on the unit display at function codes dC3, dC4 and dC5.
NOTE: The cargo probe reading can be viewed on the unit display at function code dC14.
Figure 3.34 Receptacles
The EverFRESH® controlled atmosphere option controls container atmosphere by supplying nitrogen and oxygen into the container space and simultaneously controlling levels of oxygen and carbon dioxide. Units with EverFRESH installed will typically have the label placed on the access panel.
For units with EverFRESH installed, an air compressor is installed under the condenser and several other components located in the evaporator section inside the access panels. See Section 5.9.7 for enabling or disabling EverFRESH operation on the unit.
NOTE: EverFRESH is controlled on the unit display from function codes Cd44, Cd71 and Cd76.
Detailed procedures and technical information related to the EverFRESH controlled atmosphere system can be found in the T-374 EverFRESH Manual. This can be found in the ContainerLINK™ app or from the Literature section of the Container Refrigeration website.
Table 3–1 Refrigeration System Data
|
Compressor / Motor Assembly |
Model Number |
ZMD26KVE-TFD-272 |
|
Weight (With Oil) |
42.9 kg (95 lb) |
|
|
Approved Oil |
Uniqema Emkarate RL-32-3MAF |
|
|
Oil Charge |
1774 ml (60 ounces) |
|
|
Electronic Expansion Valve (EEV) Superheat |
Verify at - 18°C (0°F) container box temperature |
4.4 to 6.7°C (8 to 12°F) |
|
Economizer Expansion Valve (EXV) Superheat |
Verify at - 18°C (0°F) container box temperature |
4.4 to 11.1°C (8 to 20°F) |
|
Heater Termination Thermostat (HTT) |
Opens |
54° (+/- 3) C | 130° (+/- 5) F |
|
Closes |
38° (+/- 4) C | 100° (+/- 7) F |
|
|
High Pressure Switch (HPS) |
Cut-Out |
25 (+/- 1.0) kg/cm2 | 350 (+/- 10) psig |
|
Cut-In |
18 (+/- 0.7) kg/cm2 | 250 (+/- 10) psig |
|
|
EXPLOSION HAZARD: Failure to follow this WARNING can result in death, serious personal injury and / or property damage. Never use air or gas mixtures containing oxygen (O2) for leak testing or operating the product. Charge only with refrigerants R-134a or R-513A as specified for the unit model number: Refrigerant must conform to AHRI Standard 700 specification. |
||
|
Refrigerant |
R-134a / R-513A |
Conforming to AHRI standard 700 specifications. |
|
Charge water-cooled condenser or receiver according to nameplate specifications to ensure optimal unit performance. |
||
|
Refrigerant Charge |
WCC Brazed Plate |
4.58 kg (10.1 lbs) |
|
Receiver |
4.26 kg (9.4 lbs) |
|
|
Fusible Plug |
Melting point |
99°C (210°F) |
|
Torque |
6.2 to 6.9 mkg (45 to 50 ft-lbs) |
|
|
Unit Weight |
Refer to unit nameplate. |
|
|
Water Pressure Switch |
Cut-In |
0.5 +/- 0.2 kg/cm2 (7 +/- 3 psig) |
|
Cut-Out |
1.6 +/- 0.4 kg/cm2 (22 +/- 5 psig) |
|
|
Circuit Breaker |
CB1 (25 amp) |
Trips at 29 amps |
|
|
CB2 (50 amp) |
Trips at 62.5 amps |
||
|
CB2 (70 amp) |
Trips at 87.5 amps |
||
|
Compressor Motor |
Full Load Amps (FLA) |
13 amps @ 460 VAC |
|
|
Condenser Fan Motor, Single Speed (571-1xx models) |
Nominal Supply |
380 VAC, 3 Phase, 50 Hz |
460 VAC, 3 Phase, 60 Hz |
|
Full Load Amps |
0.71 amps |
0.72 amps |
|
|
Horsepower |
0.21 hp (OK) |
0.36 hp (OK) |
|
|
Rotations Per Minute |
1425 rpm |
1725 rpm |
|
|
Voltage and Frequency |
360 to 460 VAC +/- 2.5 Hz |
400 - 500 VAC +/- 2.5 Hz |
|
|
Bearing Lubrication |
Factory lubricated, additional grease not required. |
||
|
Rotation |
Counter-clockwise when viewed from shaft end. |
||
|
Condenser Fan Motor, Two Speed (571-3xx models) |
Nominal Supply |
380 VAC, 3 Phase, |
460 VAC,3 Phase, |
|
Full Load Amps (H / L) |
1.0 / 0.6 amps |
1.0 / 0.6 amps |
|
|
Horsepower (H / L) |
0.21 hp / 0.03 hp |
0.36 hp / 0.04 hp |
|
|
RPM (H / L) |
1450 / 725 rpm |
1750 / 850 rpm |
|
|
Voltage Range |
360 - 460 VAC +/- 1.25 Hz |
400 - 500 VAC +/- 1.5 Hz |
|
|
Bearing Lubrication |
Factory lubricated, additional grease not required. |
||
|
Rotation |
Counter-clockwise when viewed from shaft end. |
||
|
Evaporator Coil Heaters |
Number of Heaters |
6 |
|
|
Rating |
750 watts +5/-10% each @ 230 VAC |
||
|
Resistance (cold) |
66.8 to 77.2 ohms @ 20°C (68°F) |
||
|
Type |
Sheath |
||
|
Evaporator Fan Motor(s) |
Nominal Supply |
380 VAC, 3 Phase, 50 Hz |
460 VAC, 3 Phase, 60 Hz |
|
Full Load Amps High Speed |
1.07 |
0.9 |
|
|
Full Load Amps Low Speed |
0.47 |
0.47 |
|
|
Nominal Horsepower High Speed |
0.36 |
0.63 |
|
|
Nominal Horsepower Low Speed |
0.05 |
0.8 |
|
|
Rotations Per Minute High Speed |
2850 rpm |
3450 rpm |
|
|
Rotations Per Minute Low Speed |
1425 rpm |
1725 rpm |
|
|
Voltage and Frequency |
360 - 460 VAC +/- 1.25 Hz |
400 - 500 VAC +/- 1.5 Hz |
|
|
Bearing Lubrication |
Factory lubricated, additional grease not required |
||
|
Rotation |
CW when viewed from shaft end |
||
|
Fuses |
Control Circuit |
7.5 amps (F3, F4) |
|
|
Controller / DataCORDER |
7.5 amps (F1, F2) |
||
|
Vent Positioning Sensor (VPS) |
Electrical Output |
0.5 VDC to 4.5 VDC over 90 degree range |
|
|
Supply Voltage |
5 VDC +/- 10% |
||
|
Supply Current |
5 mA (typical) |
||
|
Economizer Solenoid Valve (ESV) Coils 24 VAC |
Nominal Resistance @ 77°F (25°C) |
7.7 ohms +/- 5% |
|
|
Maximum Current Draw |
0.7 amps |
||
|
Digital Loader Valve (DLV) Coils 12 VDC (571-3xx models) |
Nominal Resistance @ 68°F (20°C) |
14.8 ohms +/- 5% |
|
|
Digital Unloader Valve (DUV) Coils 24 VAC |
Nominal Resistance @ 68°F (20°C) |
15.5 ohms +/- 5% |
|
|
Electronic Expansion Valve (EEV) Nominal Resistance |
Coil Feed to Ground (Gray Wire) |
47 ohms |
|
|
Coil Feed to Coil Feed |
95 ohms |
||
|
Humidity Sensor (HS) |
Orange wire |
Power |
|
|
Red wire |
Output |
||
|
Brown wire |
Ground |
||
|
Input voltage |
5 VDC |
||
|
Output voltage |
0 to 3.3 VDC |
||
|
Output voltage readings verses relative humidity (RH) percentage: |
|||
|
30% |
0.99 V |
||
|
50% |
1.65 V |
||
|
70% |
2.31 V |
||
|
90% |
2.97 V |
||
|
Controller |
Setpoint Range |
-35 to +30°C (-31 to +86°F) |
|
3.11Safety and Protective Devices
Unit components are protected from damage by safety and protective devices listed in Table 3–3. These devices monitor the unit operating conditions and open a set of electrical contacts when an unsafe condition occurs.
Open safety switch contacts on either or both of devices IP-CP or HPS will shut down the compressor.
Open safety switch contacts on device IP-CM will shut down the condenser fan motor.
The entire refrigeration unit will shut down if one of the following safety devices open: (a) circuit breaker(s); (b) fuse (F3 / F4, 7.5A); or (c) evaporator fan motor internal protector(s) - (IP).
Table 3–3 Safety and Protective Devices
|
Device |
Device Setting |
|
|---|---|---|
|
Excessive current draw |
Circuit Breaker (CB1, 25 amp) - Manual Reset |
Trips at 29 amps (460 VAC) |
|
Circuit Breaker (CB2, 50 amp) - Manual Reset |
Trips at 62.5 amps (230 VAC) |
|
|
Circuit Breaker (CB2, 70 amp) - Manual Reset |
Trips at 87.5 amps (230 VAC) |
|
|
Excessive current draw in the control circuit |
Fuse (F3 / F4) |
7.5 amp rating |
|
Excessive current draw by the controller |
Fuse (F1 / F2) |
7.5 amp rating |
|
Excessive condenser fan motor winding temperature |
Internal Protector (IP-CM) - Automatic Reset |
N/A |
|
Excessive compressor motor winding temperature |
Internal Protector - Automatic Reset |
N/A |
|
Excessive evaporator fan motor(s) winding temperature |
Internal Protectors (IP-EM1, IP-EM2) - Automatic Reset |
N/A |
|
Abnormal pressures / temperatures in the high refrigerant side |
Fusible Plug - Used on the Receiver. Refer to Figure 3.11 for location. |
99°C (210°F) 35 kg/cm2 (500 psig) |
|
Abnormally high discharge pressure |
High Pressure Switch (HPS) |
Opens at 25 kg/cm2 (350 psig) |
See Figure 3.35 for circuit diagram of PrimeLINE standard units (571-1xx models).
See Figure 3.36 for circuit diagram of PrimeLINE standard units (571-1xx models) with water-cooled condenser.
See Figure 3.37 for circuit diagram of PrimeLINE EDGE units (571-3xx models).
Starting at the compressor, the suction gas is compressed to a higher pressure and temperature.
The refrigerant gas flows through the discharge line and continues into the air-cooled condenser. When operating with the air-cooled condenser active, air flowing across the coil fins and tubes cools the gas to saturation temperature. By removing latent heat, the gas condenses to a high pressure / high temperature liquid and flows to the receiver, which stores the additional charge necessary for low temperature operation.
When operating with the water-cooled condenser active, the refrigerant gas passes through the air-cooled condenser and enters the water-cooled condenser shell. The water flowing inside the tubing cools the gas to saturation temperature in the same manner as the air passing over the air-cooled condenser. The refrigerant condenses on the outside of the tubes and exits as a high temperature liquid. The water-cooled condenser also acts as a receiver, storing refrigerant for low temperature operation.
The liquid refrigerant continues through the liquid line, the filter drier (which keeps refrigerant clean and dry) and the economizer (not active during standard operation) to the electronic expansion valve (EEV).
As the liquid refrigerant passes through the variable orifice of the EEV, the pressure drops to suction pressure. In this process some of the liquid vaporizes to a gas (flash gas), removing heat from the remaining liquid. The liquid exits as a low pressure, low temperature, saturated mix. Heat is then absorbed from the return air by the balance of the liquid, causing it to vaporize in the evaporator coil. The vapor then flows through the suction tube back to the compressor.
The microprocessor controls the superheat leaving the evaporator via the electronic expansion valve (EEV), based on inputs from the evaporator pressure transducer (EPT). The microprocessor transmits electronic pulses to the EEV stepper motor, which opens or closes the valve orifice to maintain the superheat setpoint.
On systems fitted with a water pressure switch, the condenser fan will be off when there is sufficient pressure to open the switch. If water pressure drops below the switch cut out setting, the condenser fan will automatically start.
During the standard mode of operation, the normally closed digital unloader valve (DUV) controls the system refrigerant flow and capacity by loading and unloading the compressor in frequent discrete time intervals. If the system capacity has been decreased to the lowest allowable capacity with the DUV, the unit will enter a trim heat mode of operation, during which the controller will pulse the evaporator heaters in sequence with the compressor digital signal in order to absorb the excess capacity.
In economized operation, the frozen and pull down capacity of the unit is increased by sub-cooling the liquid refrigerant entering the electronic expansion valve (EEV). Overall efficiency is increased because the gas leaving the economizer enters the compressor at a higher pressure, therefore requiring less energy to compress it to the required condensing conditions.
Liquid refrigerant for use in the economizer circuit is taken from the main liquid line as it leaves the filter drier. The flow is activated when the controller energizes the Economizer Solenoid Valve (ESV).
The liquid refrigerant flows through the ESV to the expansion valve internal passages, absorbing heat from the liquid refrigerant flowing to the electronic expansion valve (EEV). The resultant “medium” temperature / pressure gas enters the compressor at the economizer port fitting.
When the control air temperature falls to 2.0°C (3.6°F) above setpoint, the DUV unloads the compressor’s scroll and begins to reduce the capacity of the unit. Percentage of the unit capacity is accessed through code select 01 (Cd01). For example, if Cd01 displays 70, it indicates that the compressor is operating unloaded with the DUV engaged 30% of the time.
Figure 3.35 Refrigeration Circuit - Standard Units (571-1xx models)
1)PrimeLINE Compressor, R-513A-ready
2)Discharge Service Valve
3)High Pressure Switch (HPS)
4)Discharge Pressure Transducer (DPT)
5)Condenser
6)Receiver
7)Receiver Sight Glass
8)Fusible Plug
9)Receiver Liquid Level / Moisture Indicator
10)Liquid Line Service Valve (King Valve)
11)Filter Drier
12)Economizer
13)Economizer Solenoid Valve (ESV)
14)Economizer Expansion Valve (EXV)
15)Economizer Expansion Valve (EXV) Sensing Bulb
16)Economizer Connection
17)Electronic Expansion Valve (EEV)
18)Evaporator
19)Evaporator Temperature Sensor (ETS1 / ETS2)
20)Digital Unloader Valve (DUV)
21)Evaporator Pressure Transducer (EPT)
22)Suction Pressure Transducer (SPT)
23)Suction Service Valve
24)Flow of refrigerant back to the compressor when Economized mode is active (ESV is energized)
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Figure 3.36 Refrigeration Circuit - Standard Units with WCC (571-1xx models)
1)Compressor
2)Discharge Service Valve
3)High Pressure Switch (HPS)
4)Discharge Pressure Transducer (DPT)
5)Condenser
6)Water-Cooled Condenser
7)Coupling (Water In)
8)Water Pressure Switch
9)Coupling (Water Out)
10)Receiver
11)Receiver Sight Glass
12)Fusible Plug
13)Receiver Sight Glass / Moisture Indicator
14)Liquid Line Service Valve (King Valve)
15)Filter Drier
16)Economizer
17)Economizer Solenoid Valve (ESV)
18)Economizer Expansion Valve (EXV)
19)Economizer Expansion Valve (EXV) Sensing Bulb
20)Economizer Connection
21)Electronic Expansion Valve (EEV)
22)Evaporator
23)Evaporator Temperature Sensor (ETS1/ETS2)
24)Digital Unloader Valve (DUV)
25)Evaporator Pressure Transducer (EPT)
26)Suction Pressure Transducer (SPT)
27)Suction Service Valve
28)Flow of refrigerant back to the compressor when Economized mode is active
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Figure 3.37 Refrigeration Circuit - EDGE Units (571-3xx models)
1)PrimeLINE Edge Compressor, R-513A-ready
2)Discharge Service Valve
3)High Pressure Switch (HPS)
4)Discharge Pressure Transducer (DPT)
5)Condenser
6)Receiver
7)Receiver Sight Glass
8)Fusible Plug
9)Receiver Liquid Level / Moisture Indicator
10)Liquid Line Service Valve (King Valve)
11)Filter Drier
12)Economizer
13)Economizer Solenoid Valve (ESV)
14)Economizer Expansion Valve (EXV)
15)Economizer Expansion Valve (EXV) Sensing Bulb
16)Economizer Connection
17)Electronic Expansion Valve (EEV)
18)Evaporator
19)Evaporator Temperature Sensor (ETS1 / ETS2)
20)Digital Loader Valve (DLV)
21)Digital Unloader Valve (DUV)
22)Evaporator Pressure Transducer (EPT)
23)Suction Pressure Transducer (SPT)
24)Suction Service Valve
25)Flow of refrigerant back to the compressor when Economized mode is active (ESV is energized)
- - - - -