Gree DC Inverter Multi VRF System

2.1 Names of Main Parts

Diagrams showing main parts for GMV-36WL/C-T(U), GMV-48WL/C-T(U), and GMV-60WL/C-T(U) are provided in the original document.

2.2 Combinations of Indoor and Outdoor Units

The number of indoor units that can be connected to the outdoor unit and the total capacity of indoor units should be within 50%~135% of that of the outdoor unit.

Outdoor units of DC Inverter Multi VRF System can be connected to various indoor units. When any one of the indoor units receives operating command, the outdoor unit will start operation as per required capacity. When all indoor units stop, the outdoor unit will be shut off.

2.3 Operating Range

Cooling: Outdoor temperature: -5~48°C (23~118°F)

Heating: Outdoor temperature: -20~27°C (-4~81°F)

3.1 Standard Parts

Please use the supplied standard parts as required.

3.2 Installation Site

Consider the following when selecting the installation site:

• The unit must be installed where strong enough to withstand the weight of the unit and fixed securely, otherwise the unit would topple or fall off.
• Do not install where there is a danger of combustible gas leakage.
• Do not install the unit near heat source, steam, or flammable gas.
• Select a location which is out of children's reach. Keep the unit away from children.
• Make sure the location has space for heat exchange and maintenance so that unit can operate reliably with good ventilation.
• Install the unit where it will not be tilted by more than 5°.
• During installation, if the outdoor unit has to be exposed to strong wind, it must be fixed securely.
• If possible, do not install the unit where it will be exposed to direct sunlight (If necessary, install a blind that does not interfere with the air flow).
• Install ODU in a place where it will be free from getting dirty or getting wet by rain as much as possible.
• Install ODU where it is convenient to connect IDU.
• ODU and IDU should stay as close as possible to shorten the length of refrigerant pipe and reduce bend angles.
• Install ODU where the condensate water can be drained out freely during heating operation. Do not place animals and plants in the path of the warm air.
• Take the air conditioner weight into account and select a place where noise and vibration are small.

If the ODU is totally surrounded by walls, refer to Fig.3.1 for space dimensions (Unit: mm/inch). The diagram shows required clearances around the unit for ventilation and maintenance.

3.3 Piping Work Requirements

Refer to the table below for piping work requirements for R410A Refrigerant System:

4.1 Dimension of Outdoor Unit and Mounting Hole

Unit outline and installation dimensions are provided in Fig.4.1. The table below shows these dimensions:

4.2 Connection Pipe

4.2.1 Schematic Diagram of Piping Connection

Fig.4.2 illustrates the schematic diagram of piping connections for the VRF system.

4.2.2 Allowable Length and Height Difference of Connection Pipe

Y-type branch joints are used to connect indoor and outdoor units. Fig.4.3 shows the connecting method and allowable lengths/height differences:

4.2.3 Dimension of Pipe (Main Pipe) from ODU to the 1st Indoor Branch

The dimension of the pipe from ODU to the 1st indoor branch is determined by the dimension of the outdoor connection pipe, as shown in Fig.4.4:

4.2.4 Selection of Indoor Branches

Select indoor branches according to the total capacity of downstream indoor units (Fig.4.5):

4.2.5 Dimension of Pipe between Indoor Branches

Select pipe between indoor branches according to the capacity of downstream indoor units. If the capacity exceeds that of the outdoor unit, the capacity of the outdoor unit prevails (Fig.4.6):

4.2.6 Dimension of Pipe between Indoor Branch and IDU

Dimension of pipe between indoor branch and IDU should be consistent with the dimension of indoor pipe (Fig.4.7):

If the distance between IDU and its nearest branch is over 10m (33 feet), then the liquid pipe of IDU (rated capacity 17000Btu/h) shall be enlarged.

4.3 Installation of Connection Pipe

Follow these principles during pipe connection: Connection pipe should be as short as possible, as should be the height difference between indoor and outdoor units. Keep the number of bends as little as possible. Radius of curvature should be as large as possible.

Weld the connection pipe between indoor and outdoor units. Strictly follow the requirements for welding process. Rosin joint or pin hole is not allowed.

When laying the pipe, be careful not to distort it. Radius of bending parts should be over 200mm (8 inches). Note that pipes cannot be repeatedly bent or stretched; otherwise the material will get harder. Do not bend or stretch the pipe for more than 3 times at the same position.

4.3.1 Flaring Process

Steps for flaring:

• Use a pipe cutter to cut the connection pipe if it is unshaped.
• Keep the pipe downward in case cutting scraps get into the pipe. Clear away the burrs after cutting.
• Remove the flared nut connecting the indoor connection pipe and outdoor unit. Then use a flaring tool to fix the flared nut into the pipe (as shown in Fig.4.8).
• Check if the flared part is flaring evenly and if there is any crack.

4.3.2 Pipe Bending

Guidelines for pipe bending:

• Reshape the pipe by hand. Be careful not to damage the pipe.
• Do not bend the pipe over 90°.
• If pipe is repeatedly bent or stretched, it will get hard and difficult to bend and stretch again. Therefore, do not bend or stretch the bend for over 3 times.
• In case that direct bending will open cracks to the pipe, first use a sharp cutter to cut the insulating layer, as shown in Fig.4.10. Do not bend the pipe until it is exposed. When bending is done, wrap the pipe with insulating layer and then secure it with adhesive tape.

4.3.3 Indoor Pipe Connection

Steps for indoor pipe connection:

• Remove pipe cover and pipe plug.
• Direct the flared part of the copper pipe to the center of the screwed joint. Twist on the flared nut tightly by hand, as in Fig.4.11 (Make sure the indoor pipe is correctly connected. Improper location of the center will prevent the flared nut from being securely twisted. Thread of the nut will get damaged if the flared nut is twisted forcibly).
• Use a torque wrench to twist on the flared nut tightly until the wrench gives out a click sound (Hold the handle of the wrench and make it at a right angle to the pipe, as in Fig.4.12).

Tightening torque for pipe diameters:

Additional notes for indoor pipe connection:

• Use sponge to wrap the un-insulated connection pipe and joint. Then tie the sponge tightly with plastic tape.
• Connection pipe should be supported by a bearer rather than the unit.
• The bending angle of piping should not be too small; otherwise the piping might have cracks. Please use a pipe bender to bend the pipe.
• When connecting IDU with connection pipe, do not pull the big and small joints of IDU with force in case the capillary tube or other tubes have cracks and cause leakage.

4.3.4 Outdoor Pipe Connection

Pipe connection for GMV-36WL/C-T(U), GMV-48WL/C-T(U): Twist the flared nut on the connection pipe of outdoor valves. Twisting method is the same as for indoor pipe connection. During engineering installation, the connection pipe inside the unit must be wrapped by insulation sleeve. According to customer requirement or space limit, outlet pipe can be installed from the front, right or rear side (Fig.4.13).

Pipe connection for GMV-60WL/C-T(U): As shown in Fig.4.14 and Fig.4.15, open the outermost soundproof cotton and place a fire barrier between the compressor and straight pipe. Use a soldering gun to unsolder straight pipe 1 and straight pipe 2. Install connection pipe 1 and connection pipe 2 to the corresponding position and then seal the apertures with welding rod. First weld the liquid side connection pipe and then weld the gas side connection pipe. During welding, it's necessary to use wet gauze to wrap up the two cut-off valves. Make sure the flame won't burn the soundproof cotton or other components.

4.3.5 Installation of Y-type Branch

Y-type branches are used for connecting multiple indoor units (Fig.4.16). Use a pipe cutter to cut in the middle of the pipe section that is of proper dimension and remove burrs (Fig.4.17).

Y-type branches must be installed vertically or horizontally. Branches shall be isolated by insulating material that can bear 120°C (248°F) or even higher temperature. The attached foam of the branch cannot be taken as insulating material.

4.3.6 Thermal Insulation for Pipeline

For multi VRF systems, every copper pipe should be labeled to avoid misconnection. At the branch inlet, leave at least 500mm (19-3/4 inches) of straight pipe section.

Thermal insulation for pipeline:

1. To avoid condensate or water leakage on the connection pipe, the gas pipe and liquid pipe must be wrapped with thermal insulating material and adhesive tape for insulation from the air.
2. Joints of indoor and outdoor units should be wrapped with insulating material and leave no gap between pipe and wall (See Fig.4.18).
3. When wrapping the tape, the later circle should cover half of the former one. Do not wrap the tape too tight, otherwise the insulation effect will be weakened.
4. After wrapping the pipe, apply sealing material to completely seal the hole on the wall.

Thermal insulating material shall be able to bear the pipe temperature. For heat pump units, the liquid pipe should bear 70°C (158°F) or above and the gas pipe should bear 120°C (248°F) or above. For cooling-only units, both liquid pipe and gas pipe should bear 70°C (158°F) or above. Thermal insulating material of branches should be the same as that of the pipeline. The attached foam of branches cannot be taken as insulating material.

4.3.7 Support and Protection of Pipeline

Supports should be made for hanging connection pipes. The distance between each support cannot be over 1m (3-1/4 feet). Protection against accidental damage should be made for outdoor pipelines. When a pipeline exceeds 1m (3-1/4 feet), a pinch board should be added for protection.

4.4 Disassembly of Compressor Feet

To prevent unit damage during transportation, 2 metal pieces are fitted to the outdoor unit's compressor feet before the unit leaves the factory (See Fig.4.19). When installing the unit, these metal pieces for transportation must be removed (except for GMV-60WL/C-T(U)). Then fasten the binding nuts again and wrap back soundproofing cotton. If the unit runs with metal pieces fitted on, the compressor will shake abnormally and the unit's operating life will be shortened.

4.5 Vacuum Pumping, Refrigerant Adding

Do not purge the air with refrigerants but use a vacuum pump to vacuum the installation! There is no extra refrigerant in the outdoor unit for air purging!

4.5.1 Vacuum Pumping

The outdoor unit has been charged with refrigerant before delivery. Field-installed connection pipes need to be charged with additional refrigerant.

• Confirm whether outdoor liquid and gas valves are closed.
• Use a vacuum pump to withdraw the air inside the indoor unit and connection pipe from the outdoor valve, as shown in Fig.4.20.

4.5.2 Refrigerant Adding

Refrigerant quantity of outdoor unit before delivery:

The refrigerant amount charged before delivery does not include the amount that needs to be added to indoor units and the connection pipeline. The length of the connection pipe is decided on site. Therefore, the amount of additional refrigerant shall be decided on site according to the dimension and length of the field-installed liquid pipe. Record the amount of additional refrigerant for convenience of after-sales service.

Calculation of the amount of additional refrigerant:

Adding refrigerant method includes 2 steps:

1. Amount of additional refrigerant depending on the pipe size (X).
2. Amount of additional refrigerant depending on Quantity of IDU (Y).

Total charging amount = X + Y. Detail calculation is as follows:

1. X = (Liquid pipe length × amount of additional refrigerant per 1m)

2. Y = (Quantity of IDU - 2) × 0.3 kg (10.58 oz)

First, confirm that there is no leakage from the system. When the compressor is not working, charge additional R410A with the specific amount to the unit through the filling opening of the liquid pipe valve of the outdoor unit. If the required amount cannot be quickly filled due to pressure increase of the pipe, then set the unit in cooling startup and fill refrigerant from the low pressure check valve of the outdoor unit.

Example:

IDUs:

• Duct type GMV-N18G/A3A-D(U)
• Duct type GMV-N12G/A3A-D(U)
• Duct type GMV-ND09PLS/A-T(U)
• Duct type GMV-ND09PLS/A-T(U)

Liquid pipe:

• 9.52mm (3/8inch): A=10m (32-3/4 feet), B=5m (16-3/8 feet), C=4m (13-1/8 feet), a=3m (9-3/4 feet)
• 6.35mm (1/4inch): D=5m (16-3/8 feet), b=3m (9-3/4 feet), c=2m (6-3/4 feet), d=1m (3-1/4 feet)

1) Amount of additional refrigerant depending on the pipe size (X):

Total length of each liquid pipe:

• 9.52: A+B+C+a = 10+5+4+3 = 22m (72-3/16 feet)
• 6.35: D+b+c+d = 5+3+2+1 = 11m (36-1/16 feet)

2) Amount of additional refrigerant depending on Quantity of IDU (Y):

Quantity of indoor units: 4 sets.

Therefore, the total charging amount = (22 × 0.054) + (11 × 0.022) + (4 - 2) × 0.3 = 1.188 + 0.242 + 0.6 = 2.03 kg (71-3/5 oz).

4.6 Electric Wiring

All electrical installation must be performed by qualified technicians in accordance with local laws, regulations, and this user manual.

• Use air conditioner specialized power supply and make sure that it is consistent with the system's rated voltage.
• Do not pull the power cord with force.
• Caliber of the power cord must be large enough. A damaged power cord or connection wire must be replaced by specialized electrical cords.
• Connect the unit to a specialized grounding device and make sure it is securely grounded. It's a must to install an air switch and current circuit breaker that can cut off the power of the entire system. The air switch should include magnetic trip function and thermal trip function so that the system can be protected from short circuit and overload.
• Air conditioners belong to class I electrical appliances, so they must be securely grounded.
• The yellow-green wire inside the unit is a ground wire. Do not cut it off or secure it with tapping screws, otherwise it will lead to electric shock.
• Power supply must include a secure grounding terminal. Do not connect the ground wire to: Water pipe; Gas pipe; Drain pipe; Other places that are deemed as not secure by professional technicians.

4.6.1 Electrical Wiring

Instructions for wiring:

• For solid core wiring (Fig.4.22): Cut the wire end with a wire cutter or wire-cutting pliers, then strip the insulation about 25mm (15/16 inch). Using a screwdriver, remove the terminal screw(s) on the terminal board. Using pliers, bend the solid wire to form a loop suitable for the terminal screw. Shape the loop wire properly, place it on the terminal board and tighten securely with the terminal screw using a screwdriver.
• For strand wiring (Fig.4.23): Cut the wire end with a wire cutter or wire-cutting pliers, then strip the insulation about 10mm (3/8 inch). Using a screwdriver, remove the terminal screw(s) on the terminal board. Using a round terminal fastener or pliers, securely clamp a round terminal to each stripped wire end. Position the round terminal wire, and replace and tighten the terminal screw with a screwdriver (Fig.4.23).
• How to fix connection cord and power cord by cord clamp: After passing the connection cord and power cord through the insulation tube, fasten it with the cord clamp (Fig.4.24).

Important notes before starting work:

• Before starting work, check that power is not being supplied to the indoor unit and outdoor unit.
• Match the terminal block numbers and connection cord colors with those of the indoor unit side. Erroneous wiring may cause burning of the electric parts.
• Connect the connection cords firmly to the terminal block. Imperfect installation may cause a fire.
• Always fasten the outside covering of the connection cord with cord clamps (If the insulator is not clamped, electric leakage may occur).
• Always connect the ground wire.

4.6.2 Wiring Diagram

Connection of power cord and communication wire: Separate power supply for IDU and ODU (Fig.4.25).

Selection of air switch and power cord:

Notes on selection:

• Selection of circuit breaker and power cord in the above table is based upon the unit's maximum power (maximum current).
• Specification of power cord is based on the working condition where ambient temperature is 40°C (104°F) and multi-core copper cable (working temperature is 90°C (194°F), e.g., power cable with YJV cross-linked copper, insulated PE and PVC sheath) is lying on the surface of a slot. If the working condition changes, please adjust the specification according to national standards.
• Specification of circuit breaker is based on the working condition where the ambient temperature of the circuit breaker is 40°C (104°F). If the working condition changes, please adjust the specification according to national standards.

4.6.3 Engineering Wiring of Power Supply and Communication Cable

Please refer to Fig.4.26 & Fig.4.27 for engineering wiring. If there is a hole for a cable tie in the wiring route, please fix the wire with a cable tie. Connect the power cord and communication cable to the corresponding terminal board and grounding screw according to the wiring diagram.

Please be noted that engineering wiring cannot touch the pipe and appliance. This figure is only applicable for engineering wiring reference of power supply and communication cable. If there are differences between the figure structure and the actual unit, please refer to the actual unit. For engineering wiring, please refer to the wiring diagram provided with the unit.

5.1 Check Items after Installation

5.2 Test Operation and Debugging

(1) Test operation and debugging must be performed after finishing the first installation or replacing the main board of the outdoor unit. Otherwise, the unit won't be able to work.

(2) Test operation and debugging must be performed by professional technicians or under the guidance of professional technicians.

5.2.1 Prepare the Test Operation and Debugging

• Do not connect power until all installation work is finished.
• All control circuits and wires are correctly and securely connected.
• Check whether the fixing loops for compressor foots are removed.
• All small pieces, especially metal chips, thread ends, and forceps holders, must be removed from the unit.
• Check whether the unit's appearance and pipeline system has been damaged during transportation.
• Calculate the quantity of refrigerant that needs to be added according to the pipe length. Pre-charge the refrigerant. In case that the required charging quantity is not reached while refrigerant can't be added, record the quantity of refrigerant that still needs to add and complement the quantity during test operation. For details of adding refrigerant during test operation, see below.
• After refrigerant is added, make sure valves of the outdoor unit are completely open.
• For convenience of troubleshooting during debugging, the unit shall be connected to a PC with applicable debugging software. Make sure the unit's real-time data can be checked through this computer. The installation and connection of debugging software can be found in the Service Manual.
• Before test operation, make sure the unit is powered on and the compressor has been preheated for more than 8 hours. Touch the unit to check whether it's normally preheated. If yes, start test operation. Otherwise, the compressor might be damaged.

5.2.2 Test Operation and Debugging

Description of test operation procedures and main board display of ODU:

5.2.3 Appendix: Reference of Normal Operation Parameters

Reference parameters for normal operation:

8.1 Outdoor Heat Exchanger

The outdoor heat exchanger shall be cleaned regularly, at least once every two months. You can use a dust catcher with a nylon brush to clean away the dust on the heat exchanger. If a compressed air source is available, it can also be used to clean the heat exchanger. Do not clean it with water.

8.2 Drain Pipe

Please check regularly whether the drain pipe is blocked or not. Make sure condensate can be drained out smoothly.

8.3 Notice before Seasonal Use

• Check whether air inlets and air outlets of indoor and outdoor units are blocked.
• Check whether ground connection is reliable or not.
• Check whether batteries in the remote controller are replaced or not.
• Check whether the air filter is properly installed.
• If the unit starts up after not operating for a long time, it should be powered on 8 hours before operation starts to preheat the outdoor compressor.
• Check whether the outdoor unit is securely installed. If there is any problem, please contact a Gree authorized service center.

8.4 Maintenance after Seasonal Use

• Disconnect power of the entire system.
• Clean the air filter and outer case of indoor and outdoor units.
• Clean away the dust and obstacles on indoor and outdoor units.
• If the outdoor unit has rust, please apply some paint to it so as to prevent the rust from growing.

8.5 Parts Replacement

Parts and components can be obtained from a nearby Gree office or Gree distributor.

When conducting air tightness test and leakage test, do not mix oxygen, C2H2, or other dangerous gas into the refrigerant circuit. Otherwise, it may lead to danger. Use nitrogen or refrigerant to conduct the tests.