A system for flux residue detection is provided. The system includes a flux heater, where the flux heater controls a temperature of a flux spray applied to a printed circuit board, and an infrared camera, wherein the infrared camera provides a thermal image of the flux on the printed circuit board. A method, a computer system, and a computer program product for flux residue detection is provided, including setting flux application parameters, applying flux to a printed circuit board, and capturing an infrared image of the flux applied to the printed circuit board. A method, a computer system, and a computer program product for flux residue detection is provided, including setting flux application parameters, applying flux to a printed circuit board, capturing an infrared image of the flux applied to the printed circuit board, and determining there is excess flux residue on the printed circuit board.