BATTERY GP 3771302 - Caterpillar

Left Extender Flame Sensor, Left Main Flame Sensor, Right Extender Flame Sensor, Right Main Flame Sensor
Illustration 1 g01122098
Flame sensorAll of the flame sensors for the different screed plates operate in the same manner. The flame sensors provide inputs to the ECM. When a burner is in AUTO mode, the ECM will use the flame sensor in order to determine if a flame is present in the burner chamber. The flame sensors are also used for diagnostic purposes by determining if a flame is present in the chamber when there should be no flame. The flame sensors are located inside the burner chambers. An analog sensor is used for this function.The flame sensors provide an analog signal to the switch type inputs of the ECM. These sensors input a 0 to 5 volt signal to the ECM depending on the amount of light they are exposed to. The ECM reads this signal as either an open switch or a closed switch. These signals are read as a ground type switch. When there is no flame (light) in the burner chamber, a no flame signal is sent to the corresponding input of the ECM. This signal will be close to 5 DCV although the ECM will read the signal as no flame as long as the voltage is greater than 2.5 volts.When there is flame (light) in the burner chamber, a flame signal is sent to the corresponding input of the ECM. The signal will be close to 0 DCV, although the ECM will read the signal as a flame as long as the voltage is less than 2 volts.
Table 1
ECM Flame Sensor Logic    
Burner State     ECM Input State    
Flame Present     0 - 2.0 DCV    
No Flame     2.5 - 5.0 DCV    The following table shows the ECM connections for the different flame sensors.
Table 2
ECM Flame Sensors Inputs (1)    
Flame Sensor     Wire     ECM Contact    
Left Extender     P847-BU     J2-4    
Left Main     P848-GY     J2-5    
Right Extender     P850-PK     J2-10    
Right Main     P849-OR     J2-6    
( 1 ) The ground side connection for all flame sensors is wire P203-GN at ECM contact J1-15.