Nilfisk-Advance MC 6P Service Manual page 34

Reed Switch
A flow switch consists of a Housing, Reed Switch, Piston with Magnet, and (in some cases) a return
spring for the piston.
When water is flowing through the flow switch the piston is moved towards the reed switch. When
the piston with magnet reaches the reed switch, the reed switch closes (or opens) and gives a signal
to the control (PCBA) of the machine.
When there is no flow through the flow switch, the flow piston will in this MC 6P design drop down
due to gravity and the piston moves away from the reed switch and the reed switch will open and
break the circuit. This signal is send to the control PCBA.
It takes 20 sec. after the reed switch opens until the motor stops—equal "by-pass time".
Reed Switch
Water flow direction
SM_MC_6P Ver.2.0_2021
Function
Flow Piston
The Reed Switch is an ON/OFF
switch. Reed Switches can be N/O
(normally OPEN) or N/C (normally
CLOSED. In this model it is a N/O
switch
When a magnet comes close to the
Reed Switch it either closes or opens.
D
Flow Switch system
Flow Piston
Housing
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