The Case of the Mysterious Flame Rod

THE MYSTERY

A paint bake oven for a plating company would quit burning at random. The sensor in the flame rod was reporting no contact with fire.

THE CLUES

The CSI on the case replaced an old Honeywell flame relay, but that didn’t solve the problem. The next step was to change the wiring between the flame rod and flame relay, but that wasn’t a permanent solution. Finally the CSI disassembled the burner and discovered the burner tube was warped, which could lead to a situation where the flame became instable and lifted away from the flame rod. Unfortunately the burner tube was a $500 custom part with a 10-week lead time.

THE PERP

The ACES CSI decided that an unstable flame was the main culprit — whether caused by the warped burner or something else, the flame varied enough to stray outside the range of the flame rod’s sensor.

THE SOLUTION

The CSI replaced the flame rod with a U.V. sensor. Instead of replacing the burner tube — an expensive custom part — the CSI installed a $100 part that works fine in the unstable flame environment. Now the paint bake oven burns consistently with no interruptions.

CASE CLOSED