How to Find the Furnace Control Board in an HVAC System

If you plan on installing devices like a Wi-Fi thermostat, you’ll need to know where your furnace control board is located. The furnace control board is a circuit board that runs your home’s HVAC system. As its name implies, the control board is located in the heating portion – the furnace – of your HVAC system (although it’s often tucked away behind removeable furnace doors).

In case you need to access it, this guide will show you where the furnace control board is typically located.

Step 1: Remove the outer furnace door

The furnace in your home is probably located in a utility closet – likely in the basement. There’s often one main, outer door that is held in place by one or more screws. For the furnace shown below, there’s one removeable black screw that holds the main furnace door in place:

Beige-colored furnace of an HVAC system
The furnace door is often held in place by a removeable screw (yellow circle and arrow).

Step 2: Remove the inner furnace door

At this point you might see some electrical wires and other HVAC components, but not a circuit board. That’s because the control board is often located in the lower housing (by the blower motor) – behind yet another door. So you’ll need to remove this inner furnace door. For the furnace below, there are two removeable screws that hold the inner furnace door in place:

Multi-colored electrical wirings and components within the furnace of an HVAC system
Many furnaces have an additional inner door, also held in place by removeable screws (pink circles and arrows).

After removing the inner door, you’ll see the furnace control board:

Control board, multi-colored electrical wirings, and other components within the furnace of an HVAC system
Furnace control board (pink arrow).

Did this guide help you find the furnace control board/circuit board in your HVAC system? Let me know in the comments below!

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