Fluid Circulation Pump
©Aqua-Hot®
250-D03 Diesel Series Service Manual
REV 220302
p. 57
Burner Components
Blue Wire
Green Wire
Flame Sensor
Flame Sensor
The flame sensor is a photo resistive device which supplies the
diesel burner’s controller with a DC voltage signal when it
detects a flame. When the flame sensor senses the light of the
flame, it will shut the ignition coil off, and send a signal to the
Controller indicating that everything is working properly. If the
flame sensor does not sense the flame, it will shut the diesel
burner down in a default after 20 seconds.
Component Test: Ohms
1. Detach the diesel burner.
2. Once the diesel burner has been removed, locate and
detach the flame sensor’s green and blue wires from the
C-plug harness wires.
NOTE:
In order to perform the following procedures, it is
necessary to detach and reattach the diesel burner head.
Be sure to review the detaching/reattaching procedure
starting on Page 47.
3.
Connect the flame sensor’s green and blue wires to an
ohmmeter.
4.
Check resistance by placing a shop rag over the flame
sensor’s glass surface, to simulate a no-flame condition.
Remove the rag and expose to a light source to simulate a
flame condition.
5.
If the flame sensor is operating properly, the ohmmeter
should register high resistance, over 100K Ω when the glass
surface is covered, and less than 200 Ω when exposed to
a light source.
6. If these resistance numbers cannot be obtained, verify the
flame sensor’s glass sensor is clean. If the flame sensor is
clean and the resistance numbers cannot be obtained, the
flame sensor must be replaced.
Flame Sensor Maintenance:
1. For light dirt, dust, and/or carbon deposits, simply wipe off
the flame sensor with a soft cloth.
2. Should heavy carbon deposits be present, completely
remove the flame sensor from the photo disc and clean
with brake cleaner.
Figure 94
Figure 93
