How To Replace The Control Board On A Furnace

The control board is essentially the electronic heart of a furnace system. When you turn up the thermostat to call for heat, the thermostat sends a signal to the control board, which then signals the igniter. The process continues with the gas valve opening, a timer starting, and fans springing to action to both keep the unit stabilized and to push the warm air back out the vents. A problem with the control board can stop any part of this process from happening and leave you without heat on a cold day.

If you have determined that the problem is the control board, replacement is straightforward if you work slowly and carefully. Note that you should consult your owner's manual for further instructions before beginning because the exact layout of wires can vary depending on the make and model of your unit.

What You Need:

  • Screwdriver
  • Digital Camera
  • New Control Board

Step 1: Remove the Old Control Board

Turn off all electricity to the unit using the circuit breaker or nearby shut-off switch. Use a screwdriver to remove the screws from the lower access panel on the furnace. Pull the access panel door off and set it aside.

When you look inside, you should easily spot the control board, which is a flat panel with a bunch of wires attached. Locate the thermostat wires on the board and take a picture of the positioning of the wires if you think you will forget the orientation. Use a screwdriver to loosen the screw to the side of each wire so that you can pull the wires free.

Take a picture of the wires still attached to the board. Detach the wires by simply pulling the ends out of the board. Remove the mounting screw on the top of the control board and then pull the board straight up to remove it from its mounting plate.

Step 2: Install the New Control Board

Slide the new control board into place on the mounting plate. Screw in the fastener to hold the control board securely to the plate. Connect the wires into place on the control board working in reverse order of how you detached the wires. Start with the wires that simply pull out of the board and work up to the thermostat wires with the tightened screws. Use your pictures for orientation reference if you need the reminder.

Place the access panel door onto the furnace and screw into place. Turn the power supply back on. Turn up your thermostat to trigger the furnace into action and test to see if your problem is solved. Still experiencing issues? Look into furnace repair by Sardis Plumbing & Heating for diagnostics and part replacements.