My karcher hds 745 has started blowing fuses. it
Having a 13A fuse I am concluding that the machine is single phase. Most probably you have a faulty capacitor. Check the capacitor and if you find it expanded and leaking...then you must change it with a new one. If you see the capacitor is normal just the same it could be shorted. So change the capacitor with a new one and try to start the machine WITHOUT LOAD. Which means no water inlet and no gun attached. Doing this you can also remove temporarly the micro switches. If the motor still hums, then most probably there is a fault in the electric motor.
Now if you find out that the fault is the capacitor (which in my opinion it is the case)...you must see why the capacitor broke. If when using the machine and the gun is closed, the machine starts on and off on its own,...this will damage the capacitor. This on and off fault could come from a leaking gun. Or a leak from the seals. Whatever....the machine must not be left going ON and Off when the gun is closed. This ON and OFF could be due to faulty micro switches and control valves.
I am very sorry to mention a lot of things, but I hope as in many cases,..the changing of the capacitor will solve the problem. I wish to add that the electrical lead wire must be checked. On many occasions I found that the electrical lead wire from the plug to the machine was damaged and shorted, ..due to pulling, wear and tear.
on Feb 28, 2017