4 English 5.906-494.0 Rev. 01 (04/11)Good service work requires extensive and practice-oriented training as well as well-structured trainingmaterials.Hence we offer regular basic and advanced trainingprogrammes covering the entire product range for allservice engineers.In addition to this, we also prepare service manualsfor important appliances - these can be initially usedas instruction guides and later on as referenceguides.Apart from this, we also regular information aboutproduct enhancements and their servicing.If you should require supplements, have correctionsor questions regarding this document, please ad-dress these citing the following subject to:international-service@de.kaercher.comThe responsible product specialist will take care ofyour issue.Copying and duplication of texts and diagrams aswell as third-party access to this information ispermitted only with the explicit permission of thecompany:Alfred Kärcher GmbH & Co. KGP O Box 160D -71349 Winnendenwww.kaercher.com DangerImmediate danger that can cause severe injury oreven death. WarningPossible hazardous situation that could lead to se-vere injury or even death.CautionPossible hazardous situation that could lead to mildinjury to persons or damage to property.This service manual applies to the following applianc-es: HD 25/15-4 (1.367-121.0) HD 20/15-4 (1.367-131.0) HD 16/15-4 (1.367-105.0)The procedure for service work is the same for allthree models. Device-specific features are empha-sized in the text.– 3 piston crankshaft pump– Stainless steel piston with ceramic sleeves– Cylinder head made of brass– Pressure and suction valves made of stainlesssteel, valve cages made of plastic– Built-in large water filter protects the pump fromcontamination. The filter can be easily removedand cleaned– Oil level can be checked from the outside– 4-pin, air-cooled three-phase motor with 1400rpm.– Automatic safety switch-off after 30 minutes ofnon-operation– Winding protection contact– The pressure switch on the overflow switches themotor contactor– Soft start increases the motor speed gradually to1,400 1/min and protects the circuit from over-loads when switched on (HD 25/15-4)– Electronics in spray water protected casing.– Power nozzle, 25° spray angle– Dirt grinder– High pressure hose, NW 12 15 m (HD 25/15-4and HD 20/15-4)– High pressure hose NW 10 15 m (HD 16/15-4)– Gun EasyPress (HD 16/15-4)– Gun 300 bar (HD 20/15-4 and HD 25/15-4)1 PrefaceSubject: Fall 1082342 Safety instructions2.1 Hazard levels3 Technical Features3.1 Validity3.2 Pump3.3 Drive3.4 Electrical system3.5 FrameHD 25/15-4 Stainless steelHD 20/15-4 Steel, paintedHD 16/15-4 Steel, painted3.6 Accessories