21
Maintenance
Problem
Possible Cause
Solution
Low Water
Temperature
Improper fuel or water in fuel
Drain fuel tank and replace with proper fuel.
Low fuel pressure
Increase fuel pressure.
Weak fuel pump
Check fuel pump temperature. Replace pump if
needed.
Fuel filter partially clogged
Replace as needed.
Soot build up on coils
Clean coils with soot remover.
Lime build up on coils
Clean inside of coils using coil cleaner.
Improper burner nozzle
See Burner Specifications.
Water Temperature
Too Hot
Incoming water to machine warm
or hot
Lower incoming water temperature.
Fuel pump pressure too high
Lower fuel pressure.
Fuel pump defective
Replace fuel pump.
Detergent line sucking air
Tighten all clamps. Check detergent line for holes.
Defective high limit switch (ther
-
mostat)
Replace.
Incorrect fuel nozzle size
See Burner Specifications.
Insufficient water supplied
Check GPM to machine.
Restricted water flow
Check nozzle for obstruction, proper size.
Machine Smokes
While Burner Unit Is
Running
Or
Unit Smokes At Cold
Start Only When
Burner Is Off
Improper air adjustment
Readjust air bands on burner assembly
Fuel pressure is low <140 psi for
burner
Adjust fuel pump pressure to specifications
Burner nozzle is plugged or dirty Replace nozzle. Check parts breakdown for nozzle
size
Burner nozzle spray pattern is
faulty
Replace nozzle. Check parts breakdown for nozzle
size
Heavy accumulation of soot on
coils and burner assembly
Remove coils and burner assembly, clean thoroughly
Call local dealer
Misaligned electrode setting
Realign electrodes to specifications
Obstruction in smoke stack
Check for insulation blockage or other foreign objects
Low engine RPM
Increase RPM to correct specs. See serial plate
Fuel Pressure is too high for clean
burn (fuel PSI above 140 and
below 200) and smokes when
burner is off
Reduce fuel pressure PSI/Increase air band set for
cleaner without max water heat loss
Kärcher HPB Series Operator’s Manual 9.801-190.0 - W
