When a technician adds air to an existing gas-fired furnace, which additional loads will require power from the control transformer?

When a technician adds air to an existing gas-fired furnace, the additional loads that will require power from the control transformer include the contactor and fan relay.

The contactor is responsible for controlling the electrical power to the blower motor or other components, ensuring that they operate only when needed. This means it plays a crucial role in managing the airflow, especially when the air is added or adjusted for optimal operation of the furnace.

Similarly, the fan relay serves to switch the blower motor on and off based on the furnace cycle. When there is a change in airflow due to the addition of air, the fan relay may need to be activated to maintain proper air circulation and temperature control within the system.

Both components rely on the control transformer to provide the necessary low-voltage power for operation, ensuring that the system runs efficiently and safely. It's vital for the technician to understand these connections, as they ensure the furnace maintains proper operation and comfort in the heating system.