Kärcher HDS 9/20-4 M / HDS 10/21-4 M service schedule

1. Switch off, unplug and depressurise the machine.
2. Put a catch pan under the pump. Lever out the safety clip with a screwdriver and pull out the oil drain plug.
3. Drain the oil, then push the plug back in and secure it with the clip.
4. Fill slowly with SAE 90 to the MAX mark on the oil tank, letting air bubbles escape.
5. Take the old oil to an authorised collection point.

Tools: Catch pan (about 1 L), Flat-blade screwdriver

1. Book the annual or 500-hour service with Kärcher Customer Service or a dealer. You can also take a maintenance or safety inspection contract.
2. Ask them to check the burner, ignition, fuel filter and heating coil (soot and scale).
3. If the burner will not light: check there is fuel and water, then the fuel filter needs changing. If no spark shows in the sight glass, have Customer Service check it.
4. Never run the burner with an empty fuel tank: it destroys the fuel pump.

1. Kärcher says weekly. Switch off, pull the mains plug, close the water inlet and squeeze the gun until the machine is depressurised. Lock the gun with its safety latch.
2. Remove the sieve from the water connection, rinse it in water and refit it.
3. Unscrew the fine filter from the pump head, take out the filter insert, clean it with clean water or compressed air and reassemble.
4. Knock out the fuel sieve and clean it. Do not spill fuel.
5. Check the pump oil level. Milky oil means water in the oil: call Customer Service.
6. Monthly: pull out the detergent suction hose, clean its filter in water and refit.

Tools: Spanner for the fine filter housing, Clean water, Compressed air (optional), Drip tray

1. Book a pressure test with Kärcher Customer Service or a dealer.

1. Find your water hardness from the water supplier or with the hardness tester.
2. Use RM 110 for hard water, RM 111 for soft water.
3. Fill the system care container through its filling hole when the system care indicator light shows.
4. If the heating coil is already scaled or sooty, have Customer Service clean it.

1. High-pressure injection injuries: a jet or a pinhole leak can push water and dirt under the skin. Such a wound can look small but is serious; get to hospital at once and say it was a high-pressure injection. (General first-aid guidance, not from Kärcher.)
2. Never aim the jet at yourself, other people, animals, live electrics or the machine. Do not clean clothes or boots on you.
3. Wear gloves, goggles and protective clothing against splash-back. Kärcher says use an FFP2 mask where spray mist (aerosol) is a risk.
4. Switch off, unplug and depressurise before changing a nozzle. Lock the gun with its safety latch.
5. Check the high-pressure hose, gun and lance for cracks, bulges and leaks. Do not use the machine if anything is damaged; use only Kärcher hoses and couplings.
6. Change the nozzle as needed and push the lance home with EASY!Lock (hand tight).
7. With hot water or steam, let hoses cool or run briefly on cold water afterwards; hot parts and water can burn.

Tools: Gloves, Safety goggles

1. Drain the detergent tank.
2. Unscrew the water supply hose and the high-pressure hose.
3. Unscrew the supply line at the boiler base and let the heating coil drain.
4. Run the machine for no more than 1 minute until the pump and lines are empty.
5. Pour antifreeze into the float tank, switch on without the burner and run until the machine is completely flushed. This also gives some corrosion protection.
6. If connected to a chimney, disconnect it when it is below 0 °C.

Tools: Container