Kärcher HDS 3.9/20 Ea Cage Operator's Manual page 22

Maintenance
Troubleshooting
PROBLEM
Improper fuel or water in fuel
Low fuel pressure
Weak fuel pump
LOW WATER
Fuel filter partially clogged
TEMPERATURE
Soot build up on coils
Lime build up on coils
Improper burner nozzle
Incoming water to machine
warm or hot
Fuel pump pressure too high
Fuel pump defective
Detergent line sucking air
WATER
TEMPERATURE
Defective high limit switch
TOO HOT
(thermostat)
Incorrect fuel nozzle size
Insufficient water supplied
Restricted water flow
Improper air adjustment
Fuel pressure is low <140 psi for
MACHINE
burner
SMOKES
Burner nozzle is plugged or dirty
WHILE
Burner nozzle spray pattern is faulty Replace nozzle. Check parts breakdown for nozzle size
BURNER UNIT
Heavy accumulation of soot on coils
IS RUNNING
and burner assembly
OR
Misaligned electrode setting
UNIT SMOKES AT
Obstruction in smoke stack
COLD-START
ONLY WHEN
Low engine RPM
BURNER
Fuel Pressure is too high for clean
IS OFF
burn (fuel PSI above 140 and below
200) and smokes when burner is off
22
POSSIBLE CAUSE
Karcher HDS 505, 508, 509, 510 Operator's Manual 9.800-078.0 - R
SOLUTION
Drain fuel tank and replace with proper fuel.
Increase fuel pressure.
Check fuel pump temperature. Replace pump if needed.
Replace as needed.
Clean coils with soot remover.
Clean inside of coils using coil cleaner.
See Burner Specifications.
Lower incoming water temperature.
Lower fuel pressure.
Replace fuel pump.
Tighten all clamps. Check detergent line for holes.
Replace.
See Burner Specifications.
Check GPM to machine.
Check nozzle for obstruction, proper size.
Readjust air bands on burner assembly
Adjust fuel pump pressure to specifications
Replace nozzle. Check parts breakdown for nozzle size
Remove coils and burner assembly, clean thoroughly.
Call local dealer
Realign electrodes to specifications
Check for insulation blockage or other foreign objects
Increase RPM to correct specs. See serial plate
Reduce fuel pressure PSI/Increase air band set for
cleaner without max water heat loss