Air conditioners for an apartment: installation of multi-split systems

Recommendation points

• Installation of evaporators (splits)
• Laying the connecting bus
• Drainage options
• Outdoor unit installation
• Connection and refueling
• Maintenance and care

Why install several air conditioners in different rooms if multi-split systems with much lower energy consumption do an excellent job with this task? This article will tell you about air conditioners with a combined outdoor unit and their do-it-yourself installation..

Due to the higher complexity, air conditioners with a combined external unit are very demanding to comply with the rules of installation and connection. For self-installation, you will need a special tool: a powerful hammer drill with a 45–60 mm drill, as well as a copper tube roller, a vacuum pump and a cylinder with a filling device, the equipment can be rented. In any case, even if the installation is carried out by a contractor, it is better to control the work at all stages, the durability and performance of the system depends on it..

Installation of evaporators (splits)

Indoor units are installed on a special bracket, which is fixed to the wall strictly horizontally with several quick-fix dowels. First, choose the place of installation of the evaporator, the best option is on the outer wall or adjacent to it. Then, according to the installation map, markings of the bracket and mounting holes are applied.

If the bus is planned to be brought out from the right side of the block, the distance to the wall should not be less than 50 cm. Since the pipe connections will be located outside the case, and they cannot be walled up, this section of the bus is placed in a plastic box. On the left side of the block, the tubes can be withdrawn and bricked up immediately, so they often do this, folding the bus in a loop under the split.

Holes are made according to the markings, dowel plugs are inserted into them and the bracket is attached, the indoor unit is simply hung on the protruding horns. For ease of installation, the evaporator unit is tried on together with the connected bus. A groove is marked on it and the split is finally fixed only after the tire is laid in the groove made.

Laying the connecting bus

Laying the communication bus between the external unit and the splits is the most time-consuming stage of installation. Due to the fact that each evaporator is connected to the external unit by a separate system of channels, and the inter-unit distance can reach 30 meters, a rather large amount of work will be required. The bus consists of an interconnect wire and two or three copper tubes, clad in insulating covers. The most common insulation material is polyethylene foam, but rubber covers are more effective and last longer.

Tubes of the required length are cleaned on one side with a rimmer and rolled, then they are connected to the outlets of the indoor unit. The interconnect cable is cut, the conductors are stripped by 10–12 mm and crimped with ferrules, then connected to the terminals of the indoor unit. The other ends of the tubes must be plugged with electrical tape..

The tubing is folded with the interconnect cable and wrapped with vinyl tape with a half-turn overlap. After measuring the thickness of the resulting tire, add 50% and you will get the width and depth of the groove for laying in the wall or the dimensions of the plastic box.

The bus is marked from the bottom corner of the indoor unit. Passage holes through the walls are also made with a slope, their diameter should be 5-10 millimeters greater than the thickness of the tire. It is recommended to drill interior holes either in the corners or directly at the location of the evaporator. Before laying the tire in the groove, it is passed through all the holes to the street, then it is carefully bent at turns and laid inside.

The radius of the bends should not exceed six times the diameter of the largest copper tube. The bus must be secured inside the groove using vinyl clamps with dowel holes. It is not recommended to stack the two tires together to facilitate the sealing of the groove..

Drainage options

If it is planned to drain the drainage to the street, the gates should have a slope of 1 cm from the block for each running meter. If the drain is laid separately, the direction of the groove can be arbitrary.

Most installers run the drain directly under the outdoor unit, but this is not really the right solution. Most facades face a busy part of the street, and dripping water on passers-by is not a good idea.

When draining the drain outside, lay a drain pipe to a drain or storm drain if the unit is installed on a terrace. But in most cases, condensate discharge into the sewage system is actively practiced. In this case, it is necessary to install a water seal, which excludes the penetration of unpleasant odors into the evaporator..

The drainage branch is laid with a smooth metal-plastic or polyethylene pipe with as few joints as possible. It is necessary to observe the permissible bending radii so that the pipe does not break.

Outdoor unit installation

The external unit of the multi-split system is heavier than usual, therefore reinforced brackets are needed for its installation. In cases where there are restrictions on installation on the facade, the outdoor unit is installed on a technical balcony, terrace or roof.

The block is attached with four bolts to the bracket or bed, placing rubber shock absorbers under the legs. The outdoor unit must be installed in such a way that the margin of length of copper pipes is at least 15–20 cm.

After the external unit is fixed, interconnect wires and a power cable are connected to it. Multi-split air conditioners are characterized by high power, therefore, the outdoor unit must be connected with a solid three-core cable from the apartment panel through a separate circuit breaker.

Connection and refueling

There are multi-split systems with free and fixed number of indoor units. In the first case, each evaporator is connected to a separate collector with a group of nozzles. Fixed systems can have a combined manifold that must not be left unconnected.

The ends of the tubes are cleaned and expanded, connected to the external block according to the connection diagram. A vacuum pump is connected to the technical branch pipes of the collector, air is pumped out from the tires and the evaporator, and they are left in a rarefied state to check the tightness. If the pressure does not rise within 15–20 minutes, the system is dried with nitrogen and pumped out. The four-way valves are turned to the all-closed position and the plugs are returned to their place. Then the taps are opened, releasing the refrigerant from the outdoor unit into the system. If the recommended bus length is observed, the amount of freon in the outdoor unit is sufficient and after 10 minutes of holding the air conditioner can be started in the minimum cooling mode. Otherwise, as well as with an empty outdoor unit, refueling is required. The air conditioner is charged from a cylinder with a dosing device through technical connections. For this it is better to contact special organizations..

Maintenance and care

Multi-split systems are serviced in the same way as conventional air conditioners: cleaning the internal filter and the evaporator impeller twice a year, if possible, cleaning the outdoor unit from dust, lint and large debris.

However, due to the larger number of connections, the multi-split loses refrigerant faster, therefore it is recommended to closely monitor the system’s performance and refuel on time..