Rupture Disk; Fuel Pressure Adjustment - Kärcher HDS 3.9/20 Ea Cage Operator's Manual

Step 4 After circulating solution flush entire system
with fresh water.
Removal of Soot In Heating Coil:
In the heating process, fuel residue in the form of soot
deposits may develop between the heating coil pipe
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 coil has
been removed using the following steps:
1. Remove the tank head assembly by unscrewing
the three tek screws and lifting the tank head off.
2. Remove the two pipe nipples and associated
fittings.
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.

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 the 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 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 unit malfunction could result from con-
tamination.
Ignition Circuit:
Periodically inspect wires, spring contact and elec-
trodes for condition, security and proper spacing. For
transformer test (CAUTION 10,000 VOLTS) use
defect free insulated screwdriver and keep fingers off
blade! Lay blade across one contact: OK if arc will
span 1/2" between end of blade and other contact.
98000780-20
MAINTENANCE
Electrode Setting:
(See illustration below)
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.
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. This solenoid is activated by a pressure
switch located on the unloader valve. When an opera-
tor releases the trigger on the spray gun, the pressure
drops, allowing the pressure switch to activate 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 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
standard screwdriver (located on the fuel pump) clock-
wise to increase, counterclockwise to decrease. Do not
exceed 200 PSI.
Beckett Burner Air Adjustment
The oil burner on this machine is preset for operation at
altitudes below 1000 ft. If operated at higher altitudes, it
may be necessary to adjust the air band setting. Adjust
air band for a #1 or #2 smoke spot on the Bacharach
scale. 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.
HDS 505, 508, 509, 510 • 9.800-078.0 • Rev. 4/13
5/32" Gap
5/16"
98000780-22
Top View
Electrodes Check: Periodically check wiring connections.
If necessary to adjust electrodes, use diagram.
Electrode
Nozzles
1/16"
Side View
17