Adjusting The Safety Valve - Kärcher HDS Middle series Service Manual

Basic Settings and Service Procedures

3.9 Adjusting the safety valve

Rotating handle of the pressure and flow control valve
2
3
Pressure and flow control valve
5
6
Safety block
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1
4
HDS Middle Range / HDS Premium Range
Adjusting the safety valve
– Twist in the rotating handle (1) of the pressure
and flow control valve at the pump up to the
limit stop („+" direction).
– Pull off the rotating handle (1) from above.
– Undo the lock nut (3) for high-pressure
adjusting screw (2).
– Twist in threaded stud up to the limit stop. This
blocks the overflow valve.
– Install shut-off valve with thermometer and
pressure gauge (special tool) at the high-
pressure connection and switch on the unit.
The high-pressure connection can be directly
at the unit outlet or on the handgun in units with
hose reel.
– Slowly turn the shut-off valve until it is shut
and watch the pressure gauge to check the
pressure at which water drips out of the outlet
of the safety valve (5). Should be: 20 bar above
max. operating pressure, see Technical
Specifications.
– If the pressure is too high, turn the adjusting
screw (6) at the safety valve (5) to the left
(relax compression spring).
– If the pressure is too low, turn the adjusting
screw (6) to the right (tighten compression
spring), until the correct opening pressure is
reached, see Technical Specifications.
– Then seal the adjusting screw and reset the
pressure and flow control valve, see 3.5 and
3.6.
1 Rotating handle
2 Adjusting screw, high pressure
3 Lock nut, high pressure adjusting screw
4 Safety block
5 Safety valve
6 Adjusting screw, safety valve
Service Manual 04.2008