Liquid Level Control; Float Switches - Grundfos SLC Series Installation And Operating Instructions Manual

6. Liquid level control

6.1 Float switches

SLC and DLC control panels are available with float switches for
automatic level control. Float switches are available as
accessories. Grundfos float switches are of the non-mercury type
and are available for standard and explosion-proof pumps. The
hermetically sealed polypropylene housing and polyurethane
cable make Grundfos float switches resistant to many chemicals,
e.g. alcohol, uric acid, sewage, oils, gasoline and fruit acid.
6.1.1 SLC
The SLC can be fitted with up to three float switches:
• Minimum: Stops the pump.
• Maximum: Starts the pump.
• Alarm (optional): Indicates high water level or pump failure.
6.1.2 DLC
The DLC can be fitted with up to four float switches:
• Minimum: Stops both pumps.
• Maximum 1: Starts one pump.
• Maximum 2: Starts the other pump.
• Alarm (optional): Indicates high water level or pump failure.
Grundfos level switches for non-explosion-risk environment
Grundfos float switch MS1 UL with 33 ft (10 m) cable
Grundfos float switch MS1 UL with 40 ft (12 m) cable
Grundfos float switch MS1 UL with 60 ft (18 m) cable
Cable support of stainless steel for two float switches
Grundfos level switches for explosion-risk-environment
Grundfos float switch MS1 Ex IECex with 33 ft (10 m) cable
Grundfos float switch MS1 Ex IECex with 40 ft (12 m) cable
Grundfos float switch MS1 Ex IECex with 60 ft (18 m) cable
Cable support of stainless steel for two float switches
6.1.3 Locating and positioning the float switches
Install the float switches in the water collecting tank or pit floating
on the pumped liquid.
A float switch is an accepted way of controlling liquid levels in
tanks, pits, etc.
The position of the float switches determines when the SLC or
DLC will start and stop the pump(s).
6.1.4 Function of the float switches
Suspend the float switch, encased in a drop-shaped
polypropylene housing, at the desired height by its own three-
core cable. When the liquid reaches a certain level, the float
switch will tip either up or down, causing the contact to open or
close.
When the float switch is pointing up, the float switch contact will
be closed and the pump will start.
When the float switch is pointing down, the float switch contact
will be opened and the pump will stop.
OFF
Fig. 10 Float-switch positions
Product number
98365984
98365985
98365986
98365987
Product number
98372085
98372086
98372087
98365987
ON
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