COPELAND OME-16T-TEM CO2 Scroll Refrigeration Units Instruction Manual

COPELAND OME-16T-TEM CO2 Scroll Refrigeration Units Instruction Manual

COPELAND™ CO2 SCROLL REFRIGERATION UNITS QUICK INSTALLATION GUIDE

Introduction
This quick installation guide describes the main steps to follow for successful commissioning of the Copeland™ CO2 Scroll refrigeration unit models OME-16T-TEM & OMTE-37/49/64T-TEM. It is not intended to replace the unit’s application guidelines, to explain the functionality of the refrigeration unit or to help optimize the system parameters.

First steps
When receiving the unit, please do the following:

• Check the integrity of the unit’s transport packaging.
• Check if the unit is pressurized with 2 bar nitrogen.
• For the OME-16T model only, remove the transport bracket from the unit. Please refer to Figure 1 below and to section 3.6 “ Transport bracket ” in the unit’s application guidelines for more information.

Figure 1: Transport bracket on the OME-16T model

• Follow the instructions in the application guidelines when dealing with BOM version OM(T)E-*T-TEM--2** (split/flexible models).

The piping between the unit and the evaporators shall be designed taking into account the design pressures.
If the system piping design pressure (PS) is lower than 90 bar in the liquid line, additional safety devices are required. An additional safety device in the suction line is required in any case.
The minimum required design pressure (PS) is 80 bar for the liquid line and 60 bar for the suction line. Longer
standstill times of the unit can be achieved by a design pressure of more than 60 bar in the suction line.

The piping connection sizes of the Copeland CO2 Scroll refrigeration units are shown in Table 1 below.

Table 1: Piping connections sizes

When the piping has been finalized and the electrical supply has been connected by qualified personnel, follow the steps below in preparation for commissioning.

Safety:

• Visual inspection of the refrigerant pipes and especially of all connections.
• A type B or B+ RCD on the power supply side should be used.
• Visual inspection of the electrical wiring of the supply line.
• Checking the refrigeration unit and connected evaporators for damage of any kind.
• Ensuring that no section of the system is under safety charge with dry air.
• The installation of a CO2 gas detector is mandatory if the unit or parts of the unit are installed indoors.

Enabling the components of the OME-16T model:

• Switch on the unit main switch (Q01 – see red arrow in Figure 2 below).
• Switch on the circuit breaker for the gas cooler fan (F11).
• Switch on the circuit breaker for the crankcase heater 12 hours before compressor start-up (F2).
• Switch on the circuit breaker for the fan in the electrical cabinet (F3).
• Switch on the circuit breaker for the control circuit (F4).
• Switch on the circuit breaker for the router (data monitoring) (F5).
  
  Figure 2: Main switch and circuit breakers on the OME-16T model

Enabling the components of the OMTE-37/49/64T models:

• Switch on the unit main switch (Q01 – located on the outside of the electrical cabinet cover).
• Switch on the circuit breakers for the gas cooler fans (F11 + F12).
• Switch on the circuit breaker for the crankcase heater 12 hours before compressor start-up (F2).
• Switch on the circuit breaker for the fan in the electrical cabinet (F3).
• Switch on the circuit breaker for the service socket (F4).
• Switch on the RCD for the service socket (RCD1).
• Switch on the circuit breaker for the control circuit (F5).
• Switch on the circuit breaker for the router (data monitoring) (F6)

Figure 3: Main switch on the OMTE-37/49/64T models (only accessible from the outside)

Figure 4: Circuit breakers & service sockets on the OMTE-37/49/64T model****

Pressure resistance test and leak test
The unit has been high-pressure tested in the factory and does not need to be tested again. However, a pressure test on the high-pressure side is required in BOM version -TEM--2 (split/flexible models). The connected parts (liquid line, suction side) shall also be tested with 1.1 x PS. The pressure relief valves (PRVs) on the liquid receiver must be considered accordingly for the test on the suction side if the liquid line PS is identical to the suction line PS. The tightness of the valves between suction line and liquid receiver cannot be ensured. Therefore, one PRV on the liquid receiver must be closed by the changeover valve. The second PRV must be removed during the test and the connection closed with a plug. After the pressure test, the PRV must be reassembled. All the connections outside the unit shall be tested for leakage.

The shut-off valves (n umber 6 in Figures 5 & 6 below) in the unit can be used for the tests.

Figure 5: P &I diagram of the OME-16T model

Figure 6: P &I diagram of the OMTE-37/49/64T models

Table 2: Legend of the P &I diagrams

Evacuation

IMPORTANT
The evacuation procedure is based upon achieving an actual system vacuum standard and is NOT TIME DEPENDENT! The installation must be evacuated with a vacuum pump before commissioning. Proper evacuation reduces residual moisture to 50 ppm.
The installation of adequately sized access valves at the furthest point from the compressor in the suction and liquid lines is advisable. The system must be evacuated down to less than 3 mbar. If required break the vacuum with dry nitrogen. Pressure must be measured using a vacuum pressure gauge on the access valves and not on the vacuum pump. This serves to avoid incorrect measurements resulting from the pressure gradient along the connecting lines to the pump.

IMPORTANT
Care must be taken that all components (solenoids, expansion devices, regulators, shut off valves, etc…) in the refrigeration cycle, which separate a part of the installation when de-energized, are manually opened to ensure successful evacuation in the whole piping system.

NOTE : The controller must be switched on before starting the evacuation.

NOTE : For proper evacuation, both the HPV and BPV regulating valves must be opened using the evacuation mode in the unit controller.

To activate the evacuation mode:

1. In the GENERAL MENU select “SERVICE”

Figure 7: General menu

2. Use the UP and DOWN buttons to go to the “Evacuation” sub-menu.
3. Click on the “Evacuation” button.

Figure 8: Evacuation button in SERVICE menu

4. Click on “ENABLE”.

Figure 9: “Enable” button in the evacuation menu

5. The flashing “EVACUATION” on the main page indicates that the evacuation mode is active.

Starting the evacuation mode:
The evacuation mode will start when clicking on “ENABLE” only if the suction, discharge and liquid receiver pressures are below 10 bar. If the evacuation mode is enabled but the pressures are above 10 bar, the following message will be displayed:

• “Enabling condition for Evacuation Mode not met, waiting for it”.

Subsequently:

1. The HPV and BPV valves open directly at 100 % (the evacuation mode has priority over the valves override function).
2. The compressor(s) is/are switched off (safety timers are ignored).
3. The fan(s) is/are switched off, while auxiliary outputs are not affected (safety timers are ignored).
4. The alarms are disabled except for the communication alarms.

Stopping the evacuation mode:
The evacuation mode will be deactivated when the pressures exceed 10 bar or by clicking on the “STOP” button. When the evacuation function is stopped, the controller returns to its previous status, ie, Off or regulation.

Charging procedure

CAUTION
High pressures! Risk of system damage! Only use pressure gauges that are suitable for the required pressure positions. Check the connection hoses for suitability for CO2 pressure levels.

After pressure test, leakage test and evacuation have been performed, the system can be filled with R744 refrigerant. Check if the evacuation mode is still active before charging the system. To avoid the formation of dry ice, the system must be filled with gaseous CO2 on both sides first. Gaseous filling to 10 bar is common practice.

After filling to approximately 10 bar on both sides, liquid CO2 can be filled into the liquid receiver. After pressures in the refrigeration system and in the CO2 bottle have equalised, the missing refrigerant must be filled in gaseous form via the suction side.

For this purpose, the circuit breaker for the variable-speed compressor (F1) must be switched on and the release for the frequency inverter (SB12) must be activated – see Figures 10 & 11. In two-compressor units, the circuit breaker Q03 and the toggle switch SB22 must be activated as well. The evaporators shall be activated too.

Figure 10: Enabling the compressor via F1 and SB12 on the OME-16T model

Figure 11: Enabling the compressors via F1, Q03, SB12 & SB22 on the OMTE-37/49/64T models

The unit starts automatically. First the gas cooler fan(s) start(s) up, then the compressor(s) switch(es) on and start(s) controlling according to the suction pressure. The charging process via the suction side can be completed.

The system should be charged according to the liquid level in the liquid receiver. The system is sufficiently charged when the liquid level in the receiver is between the lower and the middle sight glass. To prevent system overcharge at high ambient temperatures, Copeland recommends charging the liquid receiver only up to 60 %. Charging must  be done with compressor(s) switched on.

NOTE: Never charge the system to a liquid level higher than the upper sight glass of the liquid receiver.

Adjusting the evaporating temperature

The CO2 scroll refrigeration unit is controlled according to the evaporating temperature. The required evaporating temperature can be adjusted via parameter SETC1.

1. Click on “Setpoint” on the main page.

Figure 12: Setpoint button on main page

2. Navigate to the required parameter using the arrow on the right.
3. Click on “SET”: now the value can be changed using the up and down buttons on the right-hand side.
4. Click on “SET” again to confirm the value.

Figure 13: Setpoints page & up & down buttons
NOTE: The setpoint for the gas cooler fan(s) is factory-set and should not be changed.

Adjusting the pump down settings

The pump down function of the CO2 scroll refrigeration unit does not work in the same way as in units using standard refrigerants. Based on the ambient temperature and the compressor set point, the controller calculates two different pump down set points:

• Set point based on ambient temperature = TAmb – SPF5
• Set point based on compressor set point = SETC1 – SPF1

The lowest pump down set point will always be applied. The following diagram illustrates the controller logic:

Figure 14: Controller logic for the pump down function
Typically, the pump down set point is adjusted by the offset defined by parameter SPF1. This parameter can be adjusted on the pump down page available in level 2 parameters.
NOTE: The pump down set point will never be lower than allowed by parameter RC2.

NOTE: Parameter RC2 can be decreased down to -20 °C to allow a lower pump down set point. Parameter SETC1 must never be set lower than -15 °C.

DISCLAIMER

1. The contents of this publication are presented for informational purposes only and are not to be construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability.
2. Copeland Europe GmbH and/or its affiliates (collectively “Copeland”), as applicable, reserve the right to modify the design or specifications of such products at any time without notice.
3. Copeland does not assume responsibility for the selection, use or maintenance of any product. Responsibility for proper selection, use and maintenance of any Copeland product remains solely with the purchaser or end user.
4. Copeland does not assume responsibility for possible typographic errors contained in this publication.

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