Maintenance - Kärcher 550.0 Operator's Manual

as can be obtained, then repeat the above procedure
on the air band setting.
Fuel Pressure Adjustment:
To adjust fuel pressure, turn the adjusting screw clock-
wise to increase, counterclockwise to decrease. Do not
exceed 200 psi. NOTE: When changing the fuel pump,
a bypass plug must be installed in the return port or the
fuel pump will not prime.
Karcher Clear Fire Oil Burner
Burner Air Adjustment: The oil burner on this machine
is preset for operation at altitudes below 1000 feet. If
operated at higher altitudes, it may be necessary to
adjust the air band for a #1 or #2 smoke spot on the
Bacharach scale.
To adjust, start machine and turn burner ON. Loosen
two locking screws found on the air band and close air
band until black smoke appears from burner exhaust
vent. Note air band position. Next, slowly open the air
band until white smoke just starts to appear. Turn air
band halfway back to the previously noted position.
Tighten locking screws.
KNA Burner Air Adjustment
Reference Numbers
Air Band Locking Screws
CAUTION: If white smoke appears from burner ex-
haust vent during start-up or operation, discontinue
use and readjust air bands.
NOTE: If a flue is installed, have a professional service-
man adjust your burner for a #1 or #2 smoke spot on
the Bacharach scale.
14

MAINTENANCE

Air Band
9.800-079.0 • Rev. 05/14
Removal of Soot and Heating Coil:
In the heating process, fuel residue in the form of soot
deposits may develop on the heating coil and block air
flow which will affect burner combustion. When soot
has been detected on visual observation, the soot
on the coil must be washed off after following the coil
removal steps.
1. Remove the tank head assembly by lifting the tank
head off.
2. Remove the two pipe nipples and associated fit-
tings.
3. Lift the coil out of the outer wrap.
CAUTION: The coil weighs about 80 lbs. Use proper
lifting techniques.
4. Clean, repair and replace the coil by reversing the
above steps.
Coil Reinstallation:
Reinstall by reversing the above steps 4 through 1.
Final Note:
The 12 VDC burner systems can draw as much as 18
amps! For such burners to run properly, the battery and
engine charging system must be kept in good condition.
The engine must run at the correct RPM to adequately
charge the battery. It is equally important not to throttle
down the engine on models without batteries, since all
power to run the burner comes solely from the engine.
Do not throttle down the engine at anytime while the
machine is operating.