Power supplies and auxiliary components refer to the electrical parts that provide power, control, and support functions for HVAC systems such as mini splits, heat pumps, and commercial units.
They do not produce heating or cooling directly — instead, they ensure the system operates safely, efficiently, and reliably.
1. Power Supplies
Power supply components deliver and regulate electricity for system operation.
Common Examples:
-
Transformers – Convert line voltage (e.g., 120V/240V) to low-voltage control power (typically 24V).
-
Power modules – Provide regulated DC voltage for control boards.
-
Disconnect switches – Allow safe electrical shutoff during service.
-
Circuit breakers & fuses – Protect equipment from overloads.
In mini split systems, the outdoor unit typically supplies power to indoor units through communication wiring.
2. Auxiliary Components
Auxiliary components support control, protection, or enhanced system performance.
Common Examples:
-
Contactors – Electrically controlled switches that activate compressors and fan motors.
-
Capacitors – Assist motors in starting and running efficiently.
-
Relays – Control signal-based switching.
-
Control boards (PCBs) – Manage system logic and communication.
-
Sensors & thermistors – Monitor temperature and system conditions.
-
Crankcase heaters – Protect compressors in cold weather.
-
Communication modules – Enable smart controls or zoning.
Why Are They Important?
These components:
-
Ensure proper voltage supply
-
Protect expensive system parts
-
Control compressor and fan operation
-
Enable safety shutoffs
-
Allow system diagnostics
-
Support smart or connected functionality
Without these electrical and support components, the HVAC system cannot operate safely or reliably.
Where Are They Located?
-
Inside the outdoor condenser
-
Inside the indoor air handler
-
In external electrical disconnect boxes
-
In separate control panels (commercial systems)
