karcher 620m pressure washer not working?

detergent not mixing with pressure lance

john perry
April 2017

Have cleaned cylinder,replaced the pressure valve, motor comes on but pressure mode will not cut in.
Any answer to this ?

dave
August 2016

can you please tell me exactly where this microswitch is and what it looks like. Thanks

Frances
January 2016

620M not working, motor runs but no pressure, it is the unloader valve that sticks if left a long time, take off the plastic micro switch held by 2 No20 torx screws then undo 4 torx screws that hold the head on, ease the valve out and clean the bore out, put the valve back in and test the plunger that operates the micro switch to make sure it springs back up freely, that should cure your problem, before you start all this make sure there isnt a blockage in the lance.

Davy62
November 2013

what oil lubes the pump and what quantity??

susan
May 2012

have done valve dismantle and re-lube etc. and seems ok but switch-on with no water connected just gives buzzing noise. surely motor should attempt start-up, or is this due to no mains water pressure to activate micro switch ? info on this was useful but need next advices please

ROBIN
June 2011

I confirm Dazzer's answer can solve the problem.

kiwibrit
May 2010

I spoke to Karcher uk who were very helpful.
No there is no reset.
In my case it was the spill valve (plunger) which was jammed this is below the micro switch, in the black plastic elbow.
The chamber I believe fills with water pushing the plunger down thus activating the motor, the micro switch in its natural state stops the pump running on dry I think.
I pulled the plunger (spill valve) out cleaned it up and greased it.
It works a treat.
Good luck.

MacG
June 2009

if there is not blockage in the lance/hose
the pressure piston is stuck and is pressing the micro switch,

it is located under the chemical tank, look for 2 torx screws holding the plastic micro switch housing, underneath is the piston

this happens when the pressure is left in the machine
water is left in the machine for long periods etc

aquaspray.co.uk
May 2009

unscrew the hose from the pump then switch on if the water comes out the and the motor fires up it could possibley have a blockage in the trigger strip down and where the hose goes in remove that then the will be a spring and a white rounded shaped jet with a small hole in if you carnt see throw it theres your problem it could of got blocked up please let me now how how get on

mike
May 2009

No, there is not a reset, however there is a pressure value and if this is stuck it will not fire the motor.

Have you tried the trigger then adjusting the lance to weak then slowly turning it to strong, this might make it kick in

Dazzer
April 2009