Nilfisk-Advance 107146895, Руководство по обслуживанию, Страница: 52 / 101

52
SM_MH 3M_4M Ver.1.2_May 2016
Function
D
MH 4M PA model, Function Unloader system
Pressure Activated Unloader— by pass (closed spray handle)
1. Motor/pump Unit.
2. Micro switch.
3. Activation arm.
4. Unloader spring.
5. Unloader piston.
6. Ball for by-pass.
7. Non return valve.
8. Ergo Spray handle.
The machine is started with closed spray handle (8).
The pressure rises until the cut-off pressure is reached.
The unloader piston (5) is pressed forward caused by the
outlet pressure exceeding the pressure from the unloader
spring → the By-pass ball (6) is moved forward and
opens the connection between the water inlet and the
water outlet (blue arrows).
The micro switch (2) is activated by the activation arm (3)
and the motor/pump (1) stops. Now the non return valve
piston (7) is pressed against its seat, which keeps the
pressure high in the hose and on the backside of the un-
loader piston.
The pressure in the pump is released to ”0” due to open
connection between pump inlet and outlet (blue arrows).
1
2
3
5
4
6
7
8
Unloader—Closed spray handle.
Motor/pump