GRUNDFOS INSTRUCTIONS
LC-Ex4
Installation and operating instructions
Declaration of Conformity
Grundfos declares under its sole responsibility that the LC-Ex4 products conform to Council directives on the approximation of laws of EC member states, specifically the ATEX Directive (94/9/EC).
Standards used include EN 60079-0:2009 and EN 60079-11:2007. The product is intended for use in potentially explosive environments, classified as II (1) G [Ex ia Ga] IIC, and requires a separate ATEX approval plate and EC-type examination certificate.
Certificate Number: DEMKO 11 ATEX 1047766X.
Declaration date: 15th January 2012, Bjerringbro, Denmark.
Notified Body: UL International Demko A/S. Manufacturer: GRUNDFOS A/S.
General Description
The Grundfos LC-Ex4 unit is an intrinsically safe Zener barrier. Its function is to ensure that signals to and from float switches never exceed a current or voltage level that could cause an explosion.
Warning: The unit is certified under DEMKO 11 ATEX 1047766X and complies with standards EN 60079-0:2009 and EN 60079-11:2007. Safety class: II (1) G [Ex ia Ga] IIC.
Application
The LC-Ex4 unit is used with LC 108 and LCD 108 controllers to manage pumps equipped with float switches in wastewater environments where explosive gases may be present.
It is designed exclusively for operation with float switches, and the basic functions of the LC 108 and LCD 108 controllers remain unchanged.
Ambient Temperature
Ambient temperature during storage and operation: -25 °C ≤ Ta ≤ +50 °C.
Electrical Connection
All electrical connections must comply with local regulations and any specific local Ex regulations.
Warning: Install the unit outside the potentially explosive area.
Warning: As the LC-Ex4 and FB-Ex4 lack galvanic separation in their safety barrier, an earth connection is required for safety.
Electrical Data
| Parameter | Value |
|---|---|
| Um | 250 V |
| Uo | 16.9 V |
| Co | 305 nF |
| Max. Lo/Ro ratio | 71 μH/Ohm |
| Po | 0.4 W |
| Io | 94 mA |
| Lo | 1 mH |
The LC-Ex4 unit has two cables for connection to the float switch inputs of the LC 108 or LCD 108 controller. Connect the float switches to the LC-Ex4 inputs as shown in the wiring diagram (Fig. B, page 16).
When connecting float switches, verify whether the switch should close or open the contact to start the pump.
Refer to the "Electrical connection" section in the LC 108 or LCD 108 controller's installation and operating instructions for further details. Consult Fig. A (page 15) for mounting and Fig. C (page 17) for the wiring diagram.
Caution: The unit must not be exposed to direct sunlight.
Installation
Intrinsically safe wiring must be installed according to EN 60079-14 (Explosive atmospheres - Part 14: Electrical installations design, selection and erection).
Mount the LC-Ex4 unit vertically (see Fig. A, page 15).
Ensure the cable diameter matches the cable gland. Use Pg 7 cable glands for earth cables (3 to 6.5 mm diameter) and Pg 9 for float switch cables (4 to 8 mm diameter).
Note: The cable sheath must remain intact throughout the cable gland and extend at least 20 mm inside the box. Strip only enough conductor insulation and cable sheath as necessary to fit the terminals inside the box.
Maintenance
Under normal operating conditions, the unit requires no maintenance. Refer to the Fault Finding Chart (Section 6) for troubleshooting.
Warning: Ensure no work is performed in a potentially explosive environment.
Warning: Before starting any work, switch off the power supply and ensure it cannot be accidentally switched back on.
Replacement of Parts
The Zener barrier unit or the entire box including the Zener barrier unit can be replaced.
Note: The Zener barrier unit must not be repaired.
Product Numbers
| Unit | Product Number |
|---|---|
| FB-Ex4, Zener barrier unit | 96538241 |
| LC-Ex4, box including the Zener barrier unit | 96440300 |
Fault Finding Chart
Fault: Not functioning
Cause: High input voltage, lightning strikes, faulty installation, etc., may cause the fuse to blow or other components to be damaged.
Remedy:
If the unit is intact, measure the resistance between the following terminals:
- 1 and 12: < 500 Ω
- 2 and 22: < 500 Ω
- 3 and 32: < 500 Ω
- 4 and 42: < 500 Ω
(Refer to Fig. C, page 17).
Measure the resistance between the following terminals:
- PE (controller side) and 31: 0 Ω
- PE (controller side) and 41: 0 Ω
Measure the resistance between the following terminals:
- AC and 11: < 500 Ω
If the measured resistances are incorrect, the FB-Ex4 unit is defective and must be replaced (see Section 5.2 Product Numbers).
Disposal
This product or its parts must be disposed of in an environmentally sound manner:
- Use public or private waste collection services.
- If this is not possible, contact the nearest Grundfos company or service workshop.
Diagram Descriptions
Figure A: Dimensions
Figure A shows the physical dimensions of the LC-Ex4 enclosure, with overall dimensions of 198 mm width and 269 mm height. It illustrates the placement of cable glands and internal components.
Figure B: Wiring Diagram
Figure B is a wiring diagram illustrating the connection between the LC 108/LCD 108 controller and the LC-Ex4 unit. It shows terminal assignments for float switches (GA1, GA2, 11, 12, 21, 22, 31, 32, 41, 42) and earth connections (PE) on both units, along with cable routing.
Figure C: Circuit Diagram
Figure C is a circuit diagram for the LC-Ex4 unit, detailing the intrinsically safe Zener barrier. It shows the connections for up to four level switches, earth connections, and the relationship between the LC 108/LCD 108 controller and the FB-Ex4 Zener barrier unit, including electrical data such as Um, Uo, Po, Io, Co, Lo, and Lo/Ro ratio.
