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Flame "sensing" - Short 136
In this short podcast, Bryan explains the basics of flame sensing, also known as flame rectification.
Flame sensing/rectification is a form of proving flame. When you can't prove flame, your furnace might be dumping unspent gas into the heat exchanger, which can cause an explosion.
Flame sensing rods are common in hot-surface (HSI) and intermittent-spark (ISI) ignition. These rods stick out into the flame and connect to the furnace board. The flame creates a path between the rod and ground, which allows a very small current to flow to the board. Without a flame, there is voltage but no path…
The skinny
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