1. Controller & Actuator Performance

Fluctuating supply voltage can cause controllers, actuators, and dampers to behave unpredictably or fail.
Example: A 24V AC actuator receiving only 19V may operate sluggishly or fail to open entirely.

2. Power Supply Sizing in BAS Panels

BAS controllers, sensors, and actuators require a stable 24V AC or DC power source.
Overloading a transformer with too many devices can result in voltage drops and erratic system behavior.

3. Voltage Tolerance for Field Devices

Most field devices tolerate a voltage variation of ±10%. Exceeding this range can lead to malfunction or permanent damage.
Example: A 24V DC sensor might operate between 20V–26V, but below or above this range, it risks failure.

4. Avoiding System Downtime

Voltage instability can cause:

• Relay chatter

• Controller resets

• Sensor misreadings

These issues reduce HVAC system efficiency and may lead to complete system breakdowns.

Pro Tip:

Always check voltage specifications of each device and properly size your power supplies to ensure a stable and reliable BAS (Building Automation System) setup.