Transformers3
HVAC equipment runs on high line voltage (typically 120V, 208V, 240V, or 480V) for the main components like compressors, blower motors, and heating elements. However, the control side—thermostats, control boards, relays, contactors, gas valves, zone dampers, and safety switches—uses low-voltage 24V AC for safety and standardization.
This type of transformer steps down the high primary voltage to safe 24V AC to power those low-voltage control circuits. The 75 VA rating indicates its power capacity (how much load it can handle before overheating); it's suitable for most residential and light commercial single-zone systems but may be undersized for large multi-zone setups with many dampers or accessories.
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