Pump Controllers; Thermal Switch, Pt1000 And Ptc Thermistor; Water-In-Oil Sensor - Grundfos SL1 Installation And Operating Instructions Manual

6.3 Pump controllers

SL1 and SLV pumps can be connected to the
following Grundfos pump controllers for level control:
• LC 231 or LC 241
• Grundfos DC and DCD.
For further information on controllers, see the
installation and operating instructions for the selected
controller or visit www.grundfos.com.
6.4 Thermal switch, Pt1000 and PTC
thermistor
All SL1 and SLV pumps have thermal protection
incorporated in the stator windings.
Pumps without sensors
Pumps without sensors have a thermal switch or a
PTC thermistor. Through the pump controller safety
circuit, the thermal switch stops the pump by breaking
the circuit in case of overtemperature (approximately
150 °C). The thermal switch close the circuit after
cooling. For pumps equipped with a PTC thermistor,
connect the thermistor to either the PTC relay or the
I/O module to break the circuit at 150 °C.
The maximum operating current of the thermal switch
is 0.5 A at 500 VAC and cos φ 0.6. The switch must
be able to break a coil in the supply circuit.
Pumps with a WIO sensor
Pumps with a WIO sensor have either a thermal
switch and a Pt1000 sensor or a PTC thermistor in
the windings, depending on the installation site.
Through the pump controller safety circuit, the
thermal switch or the thermistor stops the pump by
breaking the circuit in case of overtemperature
(approximately 150 °C). The thermal switch or the
thermistor closes the circuit after cooling.
The maximum operating current of both the Pt1000
and the thermistor is 1 mA at 24 VDC.
Non-explosion-proof pumps
When closing the circuit after cooling, the thermal
protection can restart the pump automatically through
the controller. Pumps from 4 kW and above sold in
Australia and New Zealand are fitted with a PTC
thermistor.
Explosion-proof pumps
The thermal protection of explosion-proof
pumps must not restart the pump
automatically. This ensures protection
against overtemperature in potentially
explosive environments. In pumps with a
sensor this is done by removing the short
circuit between terminals R1 and R2 in the
IO 113. See Electrical data in the
installation and operating instructions for
IO 113 (net.grundfos.com/qr/i/98097396).
22
The separate motor-protective circuit
breaker or controller must not be installed
in potentially explosive environments.

6.5 Water-in-oil sensor

The water-in-oil (WIO) sensor measures the water
content in the oil and converts the value into an
analogue current signal. The two sensor conductors
are for power supply and for carrying the signal to the
IO 113. The sensor measures the water content from
0 to 20 %. It also sends a signal if the water content is
outside the normal range (warning), or if there is air in
the oil chamber (alarm). The sensor is fitted in a
stainless-steel tube for mechanical protection.
3
2
1
WIO sensor
6.5.1 Fitting the WIO sensor
Fit the sensor next to one of the shaft seal
openings. The sensor must be tilted in the direction of
the motor rotation to ensure that oil is led into the
sensor. Make sure that the sensor is submerged in
the oil.
Related information
6.5 Water-in-oil sensor
6.5.2 Technical data
Input voltage:
Output current:
Power input:
Ambient temperature:
See the installation and operating instructions for IO
113 at www.grundfos.com.
12-24 VDC
3.4 - 22 mA
0.6 W
0-70 °C