The household split system consists of an indoor and outdoor unit, which are connected not only by copper pipes, but also by electric wires. Its service life and operational efficiency largely depend on the correct connection of the air conditioner.
In this article, we will tell you in detail how to connect both units, taking into account all the features, how to connect a modern air conditioner to the power grid and what nuances should be taken into account so that the split system will last for many years in the future.
Please note that in this article we will talk about connecting household inverter air conditioners. Their electrical circuit differs from devices for semi-industrial and industrial purposes.
Before carrying out the work, it is necessary to make preparations. Read the instructions for the air conditioner, find the electrical diagram, study the specifications. It is not necessary to carry out the work «by eye», without first studying the documentation.
Carefully study which power supply system is installed in the apartment, where the cables are located, in which places they intersect. Use additional devices to check the wall for foreign objects and internal wiring. Determine what materials the walls are made of and how susceptible they are to collapse.
If the old Soviet wiring is installed in the apartment, the connection of the air conditioner is prohibited. Also, it is not necessary to perform the work if there is no grounding. These are banal rules that many people forget about.
When laying the cable, keep in mind that switches, sockets, junction boxes should be located in an easily accessible place. A person should not have difficulty reaching for them if necessary. In this case, the outlet should be installed at a distance of at least half a meter from the floor. Laying is carried out STRICTLY in a horizontal or vertical position, no ornate bends.
When laying horizontally, it is important to take into account that there should be a distance of 10-20 centimeters between the wire and the cornice/ceiling/ ceiling skirting board. When laying vertically, the distance from the wire to the window or door opening should be at least 10 centimeters.
If there are gas pipes nearby, step back from them at least 1 meter. If there are heating pipes nearby, the wires must be insulated. It is forbidden to twist the wires when building up, instead it is necessary to use special terminals. It is also forbidden to connect wires of different composition (for example, aluminum and copper).
If the wiring will fit into a previously made recess in the wall, the cables must first be placed in a corrugated pipe. It fits into the recess together with the wires and is attached with plastic clamps in half-meter increments.
For external installation directly on the wall surface, the wiring is also attached with clamps in half-meter increments. Instead of clamps, you can use screws. If a decorative plastic box is used in the installation, the wires can be glued inside the box or use the same screws.
After installing the indoor and outdoor unit, it is necessary to connect them with a cable. An additional cable is also connected to the internal unit, it is stretched to the output of the electrical system.
A multi-core cable is used to connect the blocks, while multicolored cores are recommended so that the connection sequence is not confused in the process. The optimal cross-section for an interblock cable is 2.5 mm2.
Interblock connection briefly:
Removal of the protective cover on the unit;
Stripping the wires, connecting them to the terminals on the unit and fixing them;
Installation of the protective cover.
After connecting the air conditioner units, it is necessary to visually check whether all the wires are connected correctly. And only after careful verification, the first test run is performed.
Please note that in each individual case there may be different nuances of connection. Therefore, we do not describe the interblock connection in detail. Carefully read the instructions provided with the air conditioner, and only then get to work. Articles on the Internet will not help much, all the necessary information is in the documentation.
Connecting to the power grid
The air conditioner can be connected to the power supply either directly to the electrical panel or through an outlet. Let’s take a closer look at both options.
Through the outlet
This is the easiest way, in this case, no special preparatory work is required. In addition, for low-power window air conditioners, this option is often more profitable both from a financial and operational point of view. But please note that it is necessary to allocate a separate outlet for the air conditioner, which will be used exclusively for powering the device.
The installation algorithm is the same as in the case of interblock communication. You need to prepare the tools, study the instructions, make sure that the circuits are correct and then put the socket on. It must be connected using copper wires. Again, we will not describe each step separately, since the algorithm of actions varies depending on the air conditioner. We only tell you in general terms how the work is being done.
Of course, after connecting the air conditioner to the network, it is necessary to check whether the work is done correctly, and only then conduct a trial run.
If a powerful split system is used, it is better to connect it directly to the electrical panel. For this purpose, a separate power line is allocated. In this case, the entire main network of the apartment is not loaded with an additional source, and there are no obstacles in the form of electrical appliances between the internal unit of the air conditioner and the shield.
We have already partially told about this earlier, when we talked about the connection rules. The wire can be laid in a strobe or fixed directly on the wall. It is better to connect to the shield using a machine, having previously calculated the power.
The rest of the connection algorithm is in many ways similar to connecting to an outlet. The only difference is that the wire to which the air conditioner is connected in the apartment is laid not to the outlet, but directly into the shield.
A few words about the wires
We recommend choosing multi-core copper wires. If the air conditioner is low-power, 1.5 mm2 will be enough. For devices with a power of up to 5 kW, it is better to choose a cable with a cross section of 2.5 mm2. More powerful devices are usually connected with wires with a cross section of 4 mm2.
Most often, experienced craftsmen use a non-flammable cable of the VVG NG type in ordinary polymer insulation. It is inexpensive, while it is highly reliable and is able to work properly for up to 20-30 years. This is a great option if the optimal combination of price and quality is important.
A flat type of cable can be used for laying in the strobe, but this is often not necessary. Especially if the wire is laid in a straw and will be hidden under a layer of plaster. But, in any case, we recommend buying a non-flammable cable with the NG marking.
Is it worth installing a vending machine and an RCD?
Our opinion: circuit breakers and RCD are necessary. They provide protection against overload and short circuit, as well as prevent sudden leakage of current. We recommend installing a pair of automatic + RCD, or purchasing differential switches. The latter are more expensive, but they already have both an automatic machine and an RCD.
At the same time, the differential switch usually takes up less space than a bundle of an automatic machine and an RCD. If there is a shortage of free space in the shield, it is better to choose a differential switch. It is also easier and faster to mount than an automatic machine + RCD, which is also useful if you are an inexperienced master. In all other cases, you can save a little and take a machine + RCD.
However, the differential switch has several disadvantages. In case of a failure, the device will not be able to identify the cause and show the diagnosis, you will have to figure it out yourself. But a separate RCD will cope with this task without any problems.
Also, the automatic + RCD bundle is easier and cheaper to repair. The components can be replaced separately if necessary. If the differential switch fails, you will have to change it entirely, which, of course, is more expensive.
What should I choose? If one air conditioner is connected, it is better to overpay a thousand rubles and put a differential switch. It will save a lot of space. If several indoor units are connected, it is better to choose a bundle of automatic + RCD. It handles multiple lines better.
As you know, the indoor and outdoor air conditioner unit must be connected to each other. Also, the device must be additionally connected to the power grid using an outlet or a separate line directly into the shield.
In this article, we have described in general terms how to properly connect air conditioners and what features should be taken into account. We did not go into details on how to connect the wires of air conditioners, since the instructions may differ depending on the manufacturer and model of the device.
In any case, you should not guess and do the work «by eye». Open the instructions for the air conditioner, carefully study it. Make sure that everything is clear in the documentation, and only then get to work.
Any other questions? Ask them in the comments below. There you can also share your experience connecting an air conditioner. Give some recommendations for beginners, they will be useful for many readers. We wish you good luck!