General Troubleshooting
©Aqua-Hot®
250-D03 Diesel Series Service Manual
REV 220302
p. 95
250-D03 Unit Smoke
Purpose:
It is possible that the Aqua-Hot 250-D03 may smoke upon
first start-up. There are many possible causes for smoke as
listed below.
If the unit has sat for an extended period of time unused,
please perform the annual service.
• Clear exhaust or no smoke
○
The unit is operating correctly
• Blue/White smoke
○
Fuel Solenoid
○
Nozzle Tower
○
ETS Module
○
Short-cycling
• Black smoke
○
Low voltage
○
Exhaust system damage
○
Air intake
○
Burner is improperly seated
○
Combustion chamber damage
○
Fuel delivery system
As such, it is necessary to select the correct troubleshooting
procedure to solve the issue quickly.
Blue/White Smoke
Smoke During Start-Up or Shut-Down:
1. Ensure that the unit is not short-cycling (rapid power-up
and shut-down) during its start-up procedure. This can be
caused by:
• A faulty switch
• Damaged wiring
• A malfunctioning ETS module
2. Diagnose the ETS module by testing for continuity.
Reference Page 22 for the procedure. Test the unit after
this is complete.
3. Detach the diesel burner from the Aqua-Hot (see Page 47)
to gain access to components for testing.
4.
Remove the igniter coil flange to gain access to the fuel
tower, nozzle, igniter module, and flame sensor.
5. Visually inspect this sub-assembly, looking for any damage
or leak locations.
Smoke During the Burn Cycle:
1. It is possible that the electrodes of the igniter module
have been knocked out of adjustment.
2. Follow the directions on Page 47 to gain access to the
diesel burner head.
3. Using a Webasto electrode gauge, make sure the tips of
the electrodes fit into the grooves of the gauge.
4. Air may be present in the fuel system, resulting in the
uneven delivery of fuel to the nozzle and causing excessive
smoke. Check the fuel delivery system for any damage or
loose clamps which may introduce air into the fuel line.
5. Check the ignition coil for proper operation.
Black Smoke:
1. Ensure that the Aqua-Hot is receiving 12V DC power from
the RV.
2. Inspect the exhaust system for any damage or restrictions.
Remedy these issues.
3. Remove the access cover of the unit.
4. Attempt to shake the burner sub-assembly. If the burner
moves, it has been improperly seated. Follow the directions
on Page 47 to remove and reinstall the diesel burner.
5. If at this stage the burner is still producing black smoke,
it is recommended that the annual service be performed.
See Page 78 for the procedure.
6. Visually inspect the inside of the combustion chamber for
any warping or apparent heat damage.
7. Remove the diesel burner from the Aqua-Hot - see Page
47.
8. Remove the combustion chamber to gain access to the
heat exchanger tabs as shown in Figure 165.
9. Using a wire brush, scrub the heat exchanger inside the
Aqua-Hot as shown in Figure 165.
10. If at this stage, black exhaust smoke is not remedied,
contact the Aqua-Hot Technical Support at 574-AIR-XCEL
(574-247-9235) or locate your nearest authorized service
center.
