Karcher Steamer Pressure Valve Repair by paulrbarnard

Last crawled date: 3 years, 4 months ago

This is a repair part for a Karcher Steam Pressure Valve 4.590-105.0 safety lock.
After the steamer has been in use for a while the safety interlock can become stuck with limescale. When this happens it is not possible to unscrew the pressure valve to get it out and clean it or even to fill the water tank. The only option is to get a flat bladed screwdriver and lever off the plastic cover of the valve. This lets you get at the actual value which you can now unscrew with a pipe wrench or similar. Only do this if you are sure the washer is cold!!!!
Prying off the plastic cap result in the ring (arrowed in Green) that holds the cap to the valve shearing off. The ring is ultrasonically welded to the cap so pretty much impossible to fix back on. My solution was to print a replacement ring that fits over the bottom of the cap giving a substantial gluing area. I glued the cap and the replacement part using 5 minute epoxy.
Make sure you assemble the internals correctly (glued mine up before taking pictures...). There are three internal parts. A spring, a plastic insert and the brass thread. Hold the cover upside down (hole pointing up) and slip the spring into it. Slide the plastic insert in so that the spring sits in nicely in the recess in the insert. You will need to align the insert correctly with the cover to get it to go in. The spike on the insert needs to be pointing out of the cover. Then place the brass part over the spike and twist it until the holes in the brass part engage with the bumps on the insert. Carefully apply glue to the part shown Red. Don't get any between the plastic and the brass screw. Fit the printed part and let the glue set.
This print saved me £35 for a replacement from Karcher.