How many micro amps should a flame sensor read?
When the flame lights, you should read between 0.5 and 10 microamps (μA), depending on the furnace. Readings between 2 and 6 are common.
How much current does a flame sensor produce?
The current is very small usually less than 10ua (microamps) 10 millionths of an amp. If the flame sensor gets dirty clean it with steel wool not sandpaper. Any sand residue left behind when heated turns to glass and blocks the current flow.
How do you find the flame current?
You can measure flame signal by putting your meter (capable of measuring micro amps) in line between the flame sensor and the wire that was connected to it (see picture). If you are reading anything under 5 uA (micro amps), it is likely that your flame sensor is dirty.
What type of current is returned to the module as flame current?
The mechanics of flame sensing The voltage at the sensor is ac (alternating current), but because of the great difference in mass between the flame sensor and the furnace chassis, this voltage is “rectified” from ac to dc (direct current), usually less than 10 microamps.
What is flame rectification on a boiler?
Flame rectification is a phenomenon in which a flame can act as an electrical rectifier. This effect is used by rectification flame sensors to detect the presence of flame. The rectifying effect of the flame on an AC voltage allows the presence of flame to be distinguished from a resistive leakage path.
Can you bypass a furnace flame sensor?
Unfortunately, you cannot bypass the flame sensor and light your furnace manually, as the gas valve will not open until the flame igniter sends a signal to the control board. Attempting to manual light your furnace is very dangerous and should never be attempted.
How many volts should a flame sensor read?
Now we want to check flame sensor voltage. If the voltage is not within range there will not be enough electrical pressure to push the current through the flame. With your voltmeter, check the voltage between the sensor wire and the burner – it should be 90-107 volts AC.
How does a flame sensor create current?
The sensor is a short length of thin metallic rod that creates a small current of electricity in order to confirm there is fire burning within the furnace. As the gas valve opens to begin the combustion process, the current is sent out from the sensor in order to detect the presence of heat from a flame.
Is composed of about 95% methane?
Natural gas consists of 85–95% methane, which is the simplest hydrocarbon. Natural gas is the cleanest-burning alternative fuel.