Maintenance - Kärcher HDS 3.9/30 Operator's Manual

Deliming Coils:
Periodic flushing of coils or optional float tank is
rec om mend ed.
Step 1 Fill a container with 4 gallons of wa ter, then .
add 1 lb. of deliming pow der. Mix thor ough ly.
Pour mixture into fl oat tank.
Step 2 Remove wand assembly from spray gun and
put spray gun into fl oat tank. Se cure the trig-
ger on the spray gun into the open po si tion.
Step 3 Turn engine on, allowing solution to be
pumped through coils back into the fl oat tank.
The solution should be al lowed to cir cu late 2- 4
hours or until the color chang es.
Step 4 After circulating solution, flush the en tire
system with fresh water. Clean out fl oat tank
and then re in stall wand assembly to spray gun.
Removal of Soot from Heating Coil:
In the heating process, fuel residue in the form of soot
deposits may develop between the heating coil pipe,
and block air fl ow 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 (See Coil Removal section).
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 fi lter and drain tank every 100
hours of operation.
Use No.1 or No 2 Heating Oil (ASTM D306) only.
NEV ER use gasoline in your burner fuel tank. Gas o line
is more combustible than fuel oil and could result in a
serious ex plo sion. NEVER use crankcase or waste oil
in your burn er. Fuel unit malfunction could result from
con tam i na tion.
Fuel Control System:
This machine utilizes a fuel solenoid valve located on
the fuel pump to control the fl ow of fuel to the com bus -
tion cham ber. The solenoid, which is normally closed,
is activated by a fl ow switch when water fl ows through
it. When the op er a tor releases the trigger on the spray
gun, the fl ow of water through the fl ow switch stops,
turning off the electrical cur rent to the fuel solenoid.
The solenoid then closes, shutting off the supply of
fuel to the combustion chamber. Controlling the fl ow
of fuel in this way gives an instantaneous burn-or-no-
burn sit u a tion, there by eliminating high and low water

MAINTENANCE

tem per a tures and the combustion smoke normally
as so ci at ed with ma chines in cor po rat ing a spray gun.
Pe ri od ic in spec tion, to insure that the fuel solenoid
valve func tions properly, is rec om mend ed. This can
be done by op er at ing the ma chine and checking to
see that the burner is not fi ring when the spray gun is
in the OFF position.
Fuel Pressure Adjustment:
To control water temperature, adjust fuel pressure
by turn ing the regulating pressure adjusting screw
clock wise to in crease, counterclockwise to decrease.
Do not exceed 200 psi. NOTE: When changing fuel
pump, a by pass 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 effi ciency,
re place the nozzle each season.
Electrode Setting:
Electrode
1/8" FOR
AC CONE
Periodically Check Wiring Connections. If Necessary
HDS 600-606 • 9.800-080.0-AB
1/4" Above
Nozzle Center
3/16" FOR
DC CONE
To Adjust Electrodes, Use Diagram.
Nozzle
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