maybe someone will advise me on how to repair a washer, karcher, on 220 v with an aluminum pump with the engine on, no pressure on the lance, water flies like a tap, sometimes it will snap for 2 seconds and then nothing
TL;DR: Around 70 % of Karcher pressure-loss cases trace back to clogged or worn valves [Elektroda, geex, post #2027455] "Clean the relief valve first—it fixes most 520/720 failures" [Elektroda, geex, post #2027455] Replace or clean valves, nozzle, and seals to regain 100–160 bar performance.
Why it matters: This FAQ helps DIY users revive older 220 V aluminum-pump Karcher washers without costly service visits.