Maintenance - Kärcher HDS 4.0/32 Pe Cage - 1.575-615.0 Operator's Manual

When operating unit without a scale protection,
the heater coil may become scaled.
Rupture Disk:
If pressure from pump or thermal expansion should
exceed safe limits, the rupture disk will burst allowing
high pressure to be discharged through hose to ground.
When disk ruptures it will need to be replaced.
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 No.1 or No 2 Heating Oil (ASTM D306) only.
NEVER use gasoline in your burner fuel 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 unit malfunction could result from
contamination.
CAUTION: If the fuel pump is allowed to run dry for
any length of time it will be damaged.
Fuel Control System:
This machine utilizes a fuel solenoid valve located on
the fuel pump to control the flow of fuel to the combus-
tion chamber. The solenoid, which is normally closed,
is activated by a flow switch when water flows through
it. When the operator releases the trigger on the spray
gun, the flow of water through the flow switch stops,
turning off the electrical current to the fuel solenoid.
The solenoid then closes, shutting off the supply of
fuel to the combustion chamber. Controlling the flow
of fuel in this way gives an instantaneous burn-or-no-
burn situation, thereby eliminating high and low water
temperatures and the combustion smoke normally
associated with machines incorporating a spray gun.
Periodic inspection, to insure that the fuel solenoid
valve functions properly, is recommended. This can
be done by operating the machine and checking to
see that the burner is not firing when the spray gun is
in the OFF position.
When operating without the burner there must be heat-
ing fuel in the fuel tank. Otherwise the fuel pump has
no lubrication and will run dry. This can cause damage
to the coupling and to the fuel pump.
14
MAINTENANCE & SERVICE
9.800-103.0 - B • Karcher HDS 615-617
Fuel Pressure Adjustment:
To control water temperature, adjust fuel pressure by
turning the regulating pressure adjusting screw clock-
wise to increase, counterclockwise to decrease. Do not
exceed 200 psi. NOTE: When changing fuel pump,
a bypass plug must be installed in return port or fuel
pump will not prime.
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.
Air Adjustment:
Machines are preset and performance tested at the
factory - elevation 100'. A one-time initial correction for
your location will pay off in economy, performance, and
extended service life. If a smoky or eye-burning exhaust
is being emitted from the stack, two things should be
checked. First, check the fuel to be certain that kerosene
or No. 1 home heating fuel is being used. Next, check the
air adjustment on the blower assembly.