Kärcher HDS Middle series Service Manual

Contents

Kärcher HDS Middle series Service Manual Manual pdf 47 page image

HDS Middle Range / HDS Premium Range Unit FunctionService Manual 04.2008 Page 47 / 1272.19 Continuous-flow heaterThe water from the high-pressure pump entersthe internal heating coil winding (8) fromunderneath, is heated as it flows through andexits downwards again from the external heatingcoil winding (7).The fuel is atomised by the fuel nozzle (2) and isignited by the ignition sparks of the ignitionelectrodes (1).The combustion air from the fan (5) first flowsfrom underneath and upwards through thedouble-walled boiler jacket (6), then downwardswith the flame and passes up through the exhaustgas flue (9) into the open air as exhaust.The boiler base (3) is made from fire-resistantinsulating cement. It prevents radiation of theheat and helps to divert the flames.The burner is adjusted to good emission valuesusing the air flap on the fan (air volume) andusing the adjusting screw on the fuel pump (fuelpressure).The temperature increase at full water volume isapprox. 60-65 °C. If the water volume is reducedby the pressure and flow control valve, the watercan be heated to approx. 100 °C; if the steamnozzle is used it can be heated up to 155 °C*.Optimum burner performance is only possible ifthe heating coil is neither sooted up nor are thereany internal deposits. In addition, the ignitionelectrodes, the fuel volume and the air volumemust be correctly set.Steam operationThe following preparations have to be made forsteam operation:– Install the steam nozzle– Adjust operating pressure at the pump’spressure and flow control valve to the smallestvalue.– Set the required steam temperature at thecontrol panel.1 Ignition electrodes2 Fuel nozzle3 Boiler base4 Boiler inlet5 Air supply from burner fan6 Boiler jacket, double-walled7 Heating coil winding, external8 Heating coil winding, internal9 Exhaust connecting sleeve* Note on steam operationAccording to the Pressure EquipmentDirective, the operating pressure in the unitmust be less than 32 bar for steam operation.This is ensured by reducing the operatingpressure at the pressure and flow controlvalve and using the steam nozzle supplied.