Fuel Nozzle - Aqua-Hot 400 Series Service Manual

Burner Components Interlock Switch

Fuel Nozzle

The fuel nozzle is simply a fuel atomizer. It reduces the diesel
fuel into a fi ne spray which is mixed with incoming combustion
air, and is ignited within the combustion chamber.
Fuel Nozzle Component Test:
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 43.
1. Detach the diesel burner.
2. Hook the diesel burner up to an alternate fuel source.
• Disconnect the steel fuel lines from the diesel burner.
• Install the fuel line bypass adapter fi tting onto the
diesel burner.
• Install rubber fuel lines on both the supply and return
fuel pipes, and install the other end of the rubber fuel
lines into an adequate supply of diesel fuel. Reference
Figure 105.
Fuel Line Return
p. 58
Fuel Line Supply
©Aqua-Hot® 400D Service Manual
3. Remove both the ignition cables from the ignition
electrodes, or connect a jumper wire (with alligator clips)
across the metal tips of the electrodes.
4. Remove the B-plug from the diesel burner's controller.
5. Turn the diesel switch ON (on the interior switch panel),
and plug the B-plug back into the diesel burner's controller
to activate the diesel burner. After approximately 20
seconds, the fuel solenoid will "click" and a fi ne mist of
fuel should appear from the fuel nozzle in a cone-shaped
spray pattern.
6. Remove the B-plug from the diesel burner controller.
7. If the cone-shaped spray pattern did not appear, follow
the troubleshooting guides for the following components,
and verify they are operating properly:
• Fuel Solenoid
• Fuel Pump
• DC High-Limit Thermostats
8. If the components listed above are operating properly,
and there is still no fuel coming out of the nozzle, replace
the fuel nozzle.
Figure 105