HVAC Controls 26408-23 Complete Practice Test 2026

When a thermostat calls for heat, the system often starts with the draft inducer motor. Its job is to purge any leftover combustion gases and supply fresh air for safe and efficient burning before ignition. This ensures the burner can light properly and the heat exchanger can operate without venting problems. After the inducer runs, the control typically opens the gas valve and ignites the burner, and once heat is being produced, the blower circulates warm air through the living space. The other components listed aren’t part of the typical heat-activation sequence: the condenser fan and compressor belong to cooling, and a humidifier is an optional accessory that isn’t automatically engaged by a heat call in most setups.