Maintenance And Service; Field Repair; Electrode Setting; Burner Nozzle - Kärcher HDS 5.0/30 Ed Operator's Manual

Fuel:
Use clean fuel oil that is not contaminated with water
and debris. Replace fuel filter and drain tank every
100 hours of operation. Use Kerosene No. 1 or No.
2 Heating Fuel (ASTM D306) or diesel only. NEVER
use gasoline in your burner tank. Gasoline is more
combustible than fuel oil and could result in a serious
explosion. NEVER use crankcase or waste oil in your
burner. Fuel machine malfunction could result from
contamination.
Ignition Circuit:
Periodically inspect wires, spring contact and elec-
trodes for condition, security and proper spacing.
(CAUTION: 10,000 VOLTS)

Electrode Setting:

(See illustration below)
Side View
Electrodes Check : Periodically check wiring connections.
If necessary to adjust electrodes, use diagram.

Burner Nozzle:

Keep the tip free of surface deposits by wiping it with a
clean, solvent-saturated cloth, being careful not to plug
or enlarge the nozzle. For maximum efficiency, replace
the nozzle each season. Select nozzle size based on
the pressure washer you will be using:
Nozzle
1.50
1.75
2.00 - 2.25
All nozzles should be 60° W

Fuel Control System:

The machine utilizes a fuel solenoid valve located on
the fuel pump to control the flow of fuel to the combus-
tion chamber. This solenoid, which is normally closed,
is activated by a flow switch when water is flowing
through it. When an operator releases the trigger on
the spray gun, the flow of water through the flow switch
stops, turning off the current to the fuel solenoid. The
solenoid then closes, shutting off the supply of fuel to
the combustion chamber. Controlling the flow of fuel
14

MAINTENANCE AND SERVICE

Gap
1/8"
3/16"
Pressure Washer GPM
2 - 3
3 - 4
4 - 5
Karcher • HDS 650 • 9.800-081.0 • Rev. 5/10a
in this way gives an instantaneous burn or no burn
situation, thereby eliminating high and low water tem-
peratures, and combustion smoke normally associated
with machines incorporating a spray gun. Periodic
inspection is recommended to insure that the fuel
solenoid valve functions properly. This can be done by
operating the machine and checking to see that when
the trigger on the spray gun is in the off position, the
burner is not firing.
Fuel Pressure Adjustment:
To adjust fuel pressure, turn the adjusting screw with a
5/32" Allen Wrench (located on the fuel pump) clock-
wise to increase, counterclockwise to decrease. Do
not exceed 200 PSI.
FIELD REPAIR INSTRUCTIONS
Fuel Pump:
1. Remove the screws 10/32" Allen Head from the
machine hood.
2. Remove louvered hood.
3. With a 9/16" wrench, loosen (DO NOT REMOVE)
the two 3/8" x 3/4" HH NC serrated flange bolts
that secure the front panel.
4. With a 2.5 mm hex head wrench (Allen Wrench),
loosen the three set screws that hold the fuel pump
in the blower motor housing located on Idromatic
Boiler Assembly.
5. Carefully remove the fuel pump (Item #53) from
the blower motor, leaving the flexible zinc fuel line
connected, carefully bend the fuel line and fuel
pump away from the blower motor.
6. Locate the fuel pump/fan motor coupling.
7. Inspect the coupling for damage. The inside di-
ameter of fuel pump coupling requires flat on one
side to engage fuel pump, and the outside diameter
requires two male notches to engage the blower
motor.
8. Perform a check to see if the fuel pump is turning
freely. Use an open end 7mm wrench or small
adjustable wrench on fuel pump shaft.
9. Spin the fuel pump over in both directions using
the wrench for leverage. When the fuel pump is
turning freely (almost to the point you could turn it
by hand) it is ready to reinstall.