Flame Rod Sensor Circuit

Flame sensing rods stick out into the flame and connect back to the furnace board.

Flame rod sensor circuit.

Most every flame rod system i have worked on puts and ac voltage on the flame rod. The other connection in the circuit is the flame being in contact with a metal surface that acts as a ground. In a nutshell the flame rectification system is an electrical process that causes a low level dc current to be conducted from the. It is essentially fail safe.

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. Also some tips for servicing. If abnormal situations exist such as open circuits short. Proves flame at the point of ignition.

This video is part of the heating and cooling series of. If proof of flame is not present the icm will de energize the gas valve and retry for ignition or lockout. It does this by generating a potential voltage at the flame sensing terminal this terminal is connected to the sensor with a conductor. Flame rods are found on nearly all induced draft burner systems and on many forced draft burners.

The flame rod in your picture is not a thermocouple. After cleaning you should reinstall the flame sensor and take another reading in order to see how much you improved flame signal. This one explains the electronics behind the flame rod control system. This is known as a flame sensor or flame rod.

A special metal rod is mounted in the path of the flame. Disconnect the flame sensor wire from sensor. In a nutshell the flame rectification system is an electrical process that causes a low level dc current to be conducted from the. Once the board sends a call to the gas valve to open it monitors the current flow on the flame sensing rod.

Depending on the system this voltage may be between 80 and 300 volts. Flame rods have the following advantages. Because of the flexibility of positioning a flame rod a pilot flame can be proven at the point of intersection with the main flame. Troubleshoot flame sensor the flame sensor in any furnace proves combustion.

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. Flame rods are found on nearly all induced draft burner systems and on many forced draft burners. When no flame. This is known as a flame sensor or flame rod.

The cpfs circuit 31 of the flame detector generates a comparable microampere dc current in response to a flame pulse signal in the 10 500 hz frequency range so that the uv flame detector can be used in place of a flame rod sensor with an existing burner control combustion safeguard circuit. Connect a micro amp meter in series with this wire and the. To troubleshoot flame sensor.