When replacing the control board of an air conditioner, it is ideal to maintain the originality of the equipment. However, sometimes this is not possible, and universal control boards must be used. A key aspect is determining whether your air conditioner requires a board with PG (Gate Pulse) or without PG, as this directly affects the control of the indoor unit’s fan.
What Is a Control Board with PG?
Control boards with PG use advanced electronic systems to control fan speeds through a device called a TRAC (Trigger or Gate). This device precisely regulates the voltage supplied to the fan motor, allowing for more efficient and accurate speed adjustments.
What Is a Control Board without PG?
In contrast, control boards without PG manage fan speeds using mechanical relays. These boards physically switch speeds by altering connections between the power supply wires and the common pins of the motor coils.
How to Identify the Type of Control Board You Need
1. Check the Fan Connection
Boards with PG:
- The fan motor has three thick wires: Common, Start, and Run.
- It also features a Hall-effect sensor with three thin wires responsible for sending speed signals to the board.
- These connections enable electronic and precise fan speed variation.
Boards without PG:
- The fan motor has at least five equally thick wires corresponding to different speeds (Start, Run, and three commons).
- There is no Hall-effect sensor; instead, mechanical relays are used to alternate speeds.
2. Inspect the Old Control Board
Boards with PG:
- Do not have consecutive relays visible for speed control.
- Look for a specific connector for the Hall-effect sensor.
Boards without PG:
- Have three to five consecutive relays dedicated to switching fan speeds.
The Role of the Hall-Effect Sensor
In boards with PG, the Hall-effect sensor plays a crucial role in monitoring fan speed. This sensor:
- Provides RPM (revolutions per minute) signals to the board.
- Has three thin wires for connection (signal, ground, and power).
- If the sensor is incorrectly connected or faulty, the board will shut the unit down automatically.
Hall-Effect Sensor Emulation
If using a universal board and you need to emulate the presence of a Hall-effect sensor, some boards allow you to use a jumper or switch connecting the signal and ground pins. This tricks the board into thinking the RPM is correct, enabling the system to operate.
Summary
- Boards with PG: Three thick wires for the fan and a Hall-effect sensor with three thin wires.
- Boards without PG: At least five thick wires for the fan and no Hall-effect sensor.
