HDS Middle Range / HDS Premium Range
Troubleshooting
Service Manual 04.2008
Page 117 / 127
5 Troubleshooting
Measure
Unit is not running (no LED
display)
– Check/replace mains voltage, connection cable and mains
fuse.
– Check fuse (F1).
– Check/replace unit switch.
– Check/replace the pressure switch.
– Check/adjust/replace control circuit transformer.
– Check/replace the thermal fuse.
– Check/replace printed circuit board and soft start.
– Check/replace contactor (K1).
Fault
Motor thermal contact has
actuated
– Switch off unit and leave to cool. Correct fault and switch unit
back on again.
Water pressure too low
– Check/increase water supply volume.
– Check/clean/replace water fine filter.
– Vent the unit.
– Check /replace high-pressure nozzle.
– Check pressure and suction valves for leaks/replace.
– Check/adjust/replace overflow valve.
– Check/adjust/replace safety valve.
Water is not heated
– Check/correct temperature setting.
– Ensure adequate water supply when low-water protection is
switched off/repair low-water protection.
– Check/top-up fuel level in the tank.
– Check/replace fuel pump solenoid valve.
– Check/clean/replace fuel filter.
– Check/correct fuel pump setting.
– Check/replace the fuel nozzle.
– Check/replace ignition cable.
– Check/correct ignition electrode spacings.
– Check/repair burner fan.
– Check/correct air flap setting.
Indicator LED is lit
– See Chapter 3.1
Insufficient or no cleaning
agent function
– Check/correct metering valve setting.
– Check/top up cleaning agent tank.
– Check/clean/replace cleaning agent filter.
– Check/replace cleaning agent suction hose, metering valve
and cleaning agent suction at the cylinder head.
– Check handgun and O-rings on high-pressure hose for leaks/
replace.
– Check non-return valve for leaks/replace O-rings.
– Check/adjust/replace overflow valve.
– Check/replace the pressure switch and control piston.
Pressure drop in the high-
pressure system