What causes a flame sensor to go out?

What are causes of a dirty flame sensor? As with any piece of equipment a simple reason could be that dirty flame sensor just goes bad. However a more common reason is that it is just dirty. It is a sensitive sensor so any type of dust or carbon buildup could cause it to malfunction.

Why is my flame sensor not working on my furnace?

Alternately, on furnaces that do not have a flame current pad, the micro amp measurement must be read by placing a meter set to DC Amps in series with the flame sensor and the control board. One of the most common causes of flame failure is the sensor. Keep in mind that the control is sending out an A/C voltage signal.

What causes a furnace controller to lock out?

Here are the most common lockout culprits explained. Defective flame sensors are one of the most common causes of lockouts. When your furnace begins to start, the sensor checks for the presence of fire. If the sensor is faulty or dirty, it won’t be able to detect the flame and the controller will stop the ignition sequence.

How is a flame sensor attached to a control module?

A flame sensor is nothing more than a stainless steel rod partially encased in porcelain. By itself, it does nothing. There are no moving parts, no switches. When attached to a control module, the module sends out an A/C voltage to the sensor. This voltage is always present at the sensor.

What happens when a flame sensor becomes corroded?

Keep in mind that the control is sending out an A/C voltage signal. If the sensor becomes dirty or corroded, it is like covering that stainless steel probe with insulation and the current can not pass to the flame (ground) and create the D/C signal back to the board.

What should I do if my flame detector is not working?

The flame detector circuit is seeing a flame signal when the gas valve is closed. • Verify flame is not present. If present, turn off gas supply and replace gas valve. • Check supply voltage for proper polarity. • Check external wiring for voltage feedback. • Check the flame rod and make sure it is clean.

How to troubleshoot a pilot flame on a burner?

Verify gap between pilot hood/burner and electrode ELECTRONIC CONTROL MODULE TROUBLESHOOTING (GENERAL) Pilot flame does not light 6. Follow wire from module to controlling device. Disconnect wire at controlling device and check for voltage as designated by Manufacturer. a. If no, check continuity of wire and replace if necessary b.

What to do if your boiler has lost flame signal?

Press the RESET button on the display to reset.) The unit has lost flame signal four (4) times during a call for heat. • Inspect spark electrode and associated wiring for damage and connection. • Check for proper electrical grounding of the unit. • Check incoming supply gas pressure.

Why is the fan not working on my Lochinvar boiler?

The unit has failed to prove main burner ignition after four (4) attempts. The fan speed is being increased due to the flame current going below 5 microamps. The flue temperature has exceeded 250°F. • Inspect the heat exchanger.