VRV and VRF air conditioning systems

Electrical diagram of the air conditioner

Hydraulic diagrams of air conditioners can provide comprehensive information about a particular device. In particular, they include the basic diagrams of air conditioners that may be needed during the repair or self-assembly of such equipment in order to better understand the features of the air conditioner.

In this article, we will show two electrical circuits — for the external unit and for the internal one, since it is from two blocks that the standard split system consists.

Electrical diagrams of air conditioners

External block

Electrical diagram of the external unit


  • C-output of windings at the compressor;

  • R — working winding of the compressor;

  • S-phase-shifting (starting) winding of the compressor motor;

  • Internal overload protector — built-in overload protection;

  • Compressor capacitior — the condenser.

  • Thermal protector — built-in protection against motor overheating;

Terminal — terminal block, designed for connecting the cable connecting the blocks;

  • N-neutral;

  • 2-power for the compressor is supplied here from the control board of the indoor unit;

  • 3-here is the power supply for the fan motor, first speed;

  • 4 — power supply for the fan motor, second speed;

  • 5-power supply for the valve responsible for switching the air conditioner to the air heating mode.

SV — activates the valve responsible for switching the air conditioner to the air heating mode.

Indoor unit

Indoor unit wiring diagram


Control Board — control board, responsible for all devices, displays information on the built-in display;

Thermistor — in a simple way, a temperature sensor;

  • Room temp-indoor air temperature sensor;

  • Pipe temp-temperature sensor for the evaporator and heat exchanger tubes.

Display board — is responsible for the display, often it is several LEDs that signal the air conditioner is turned on or in a different state;

Terminal block

  • L-single-phase electrical supply line;

  • N-neutral single-phase power supply.

Filter Board — reduces the level of interference in the power supply;

Main relay — the main (power) relay that supplies voltage to the compressor;

Drain pump motor — drain pump or drain pump;

  • Float switch-level sensor in the pump, float type.

Step motor — literally stepper motor.


This article shows the diagrams of the external and internal blocks. They are taken from the technical documentation supplied with one of the popular models of the air conditioner. These are simple and clear diagrams of the device, you can use them for personal purposes to repair or assemble a similar unit. Good luck!

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