Flame Rod Sensor Circuit

Once the board sends a call to the gas valve to open it monitors the current flow on the flame sensing rod.

Flame rod sensor circuit.

If proof of flame is not present the icm will de energize the gas valve and retry for ignition or lockout. Because of the flexibility of positioning a flame rod a pilot flame can be proven at the point of intersection with the main flame. I am using 12v ac at the input and at the output flame sensing circuit which is made of opamp some resistors and capacitors i get 1 6 2 4v when there is a flame and 3 8 4v when there is a short circuit and 5v when there is no flame. If abnormal situations exist such as open circuits short.

Also some tips for servicing. Flame rods are found on nearly all induced draft burner systems and on many forced draft burners. This is known as a flame sensor or flame rod. Disconnect the flame sensor wire from sensor.

After cleaning you should reinstall the flame sensor and take another reading in order to see how much you improved flame signal. Connect a micro amp meter in series with this wire and the. This video is part of the heating and cooling series of. A special metal rod is mounted in the path of the flame.

Depending on the system this voltage may be between 80 and 300 volts. Flame rods are found on nearly all induced draft burner systems and on many forced draft burners. In a nutshell the flame rectification system is an electrical process that causes a low level dc current to be conducted from the. The other connection in the circuit is the flame being in contact with a metal surface that acts as a ground.

The sensor needs to be cool to the touch when you clean it so it doesn t melt the scotchbrite pad and leave a residue on the flame rod. To troubleshoot flame sensor. When no flame. Flame sensing rods stick out into the flame and connect back to the furnace board.

Most every flame rod system i have worked on puts and ac voltage on the flame rod. In a nutshell the flame rectification system is an electrical process that causes a low level dc current to be conducted from the. I am sensing a flame using a flame rod. This one explains the electronics behind the flame rod control system.

This is known as a flame sensor or flame rod. Quick response to flame failure. It is essentially fail safe. A special metal rod is mounted in the path of the flame.

The flame rod in your picture is not a thermocouple. Proves flame at the point of ignition. It does this by generating a potential voltage at the flame sensing terminal this terminal is connected to the sensor with a conductor.