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Precise Controls for Building Automation & Commercial HVAC Systems

Browse building automation and commercial HVAC controls at F.W. Webb. A control board is the heart of an HVAC's operating system, in charge of powering the thermostats that control the temperature of the building. Find replacement control modules and high-quality programmable controllers to accommodate your system's needs. Explore accessories for the control board, including software programming tools, wall plates, and mounting kits. Discover powerful HVAC control boards from Source 1, Johnson Controls, and other trusted makers at F.W. Webb.

Frequently Asked Questions

What does an HVAC control board do?

An HVAC control board serves several purposes:

  • Input: An HVAC control board receives information from the thermostat to heat or cool the home or building it's installed in.
  • Safety: The control board monitors sensor input for potential issues, and makes decisions to keep valves open in the case of an ignitor failure, for instance.
  • Communication: A control board can save error codes to relay them back to you in the event of a data malfunction.
  • Power: A transformer sends voltage to the control board, which is distributed to the thermostats throughout the house.

How do you know if your control board is bad?

To check if your control board is bad, follow these steps:

  • Remove the access panels and inspect the control board for burns or odd smells.
  • Check the diagnostic light to see if it's blinking several times to indicate a problem.
  • Try powering it on if the light is not blinking. If there is no power and no light, the control board most likely needs replacement.
  • After confirming there is no power, test the furnace's terminals. If the furnace powers on after jumping the terminals, the problem is with the thermostat rather than the control board.
  • Test the power of your control board while referring to the wiring diagram to follow the furnace's sequence of operations. If there aren't additional issues with the furnace, your control board probably needs replacing.
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