Table 3-3. Unit Maintenance Troubleshooting Continued
TEST OR INSPECTION
Step 3. Check fuel/air mixture.
Open front access door (1)
and adjust fuel needle (2)
When turning needle valve all the way in, do
not force. Use light pressure to avoid dam-
age to valve.
Turn fuel needle (2) clockwise as far as possible.
Turn fuel needle (2) counterclockwise in 1/8-turn increments. Increase
fuel flow until there is no odor of unburned fuel and no smoke in
In low ambient temperatures it may be necessary to increase fuel flow
to achieve smooth burner operation.
Step 4. Check exhaust system for blockage, kinks, or bends.
Straighten exhaust line or replace as needed.
5. HEATER SMOKES
Check fuel/air mixture.
Refer to malfunction 4, step 3.