HDS Middle Range / HDS Premium Range
Unit Function
Service Manual 04.2008
Page 59 / 127
2.27 Pressure switch function
1 High-pressure outlet (unpressurised)
2 Pressure gauge (unpressurised)
3 Non-return valve (closed)
4 Rotary knob
5 Overflow valve (closed)
6 Throttle bore
7 Pressure switch, „OFF“ (closed)
8 Water inlet
9 Motor protection contacts (K1) (open)
10 Pump is at a standstill
11 Pressure switch, „ON“ (closed)
2.27.1 Unit is switched off
When the unit is switched off and the handgun is
open, the system is unpressurised and off-load.
Both pressure switches (7) and (11) as well as
the overflow valve (5) and the non-return valve
(3) are closed. The motor protection contacts (9)
are open (see circuit diagram).
1
2
3
5
6
7
8
10
11
9
0 volt
Note
The function of the pressure switches and
the motor contactor described is only to help
you to understand the function better. In
reality the information from the two pressure
switches is sent directly to the electronic
control circuits and these then control the
motor contactor.
4