Gas Furnace

Re: Low Flame Signal

A gas furnace lights and burns properly, but the flame signal is low.

► This condition will often cause periodic "flame loss" failures.

How It Works:

• The ignition control board sends-out a small voltage signal over the flame sensor wire.
• The resistance between the flame sensor rod, through the flame, to the grounded burner generates a small amount of amperage (microAmps).
• Anything that reduces the resistance from the flame rod to the grounded burner will cause a low microAmp signal.