FCL18-02 Series

Multifunction Liquid Level Relay
6 Selectable Modes — Fill & Empty

Versatile liquid level control with 6 configurable modes (A–F), adjustable sensitivity (5–100 kΩ), and configurable time delay (0.1–10s). Supports both 1-probe and 2-probe operation — the ultimate solution for all tank filling and emptying applications in one compact 18mm unit.

12–240V AC/DC Supply 6 Modes (A–F) Fill & Empty Functions 1 or 2 Probe Levels Sensitivity 5–100 kΩ Time Delay 0.1–10s DIN rail mount 18mm slim design 1×SPDT 16A Low-Voltage Probes IP40 Front
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FCL18-02 Multifunction Liquid Level Control Relay
🎚️ 6 Selectable Modes (A–F) Fill, empty, delayed fill/empty, and overrun timer functions for both 1‑probe and 2‑probe applications.
⚡ 1 or 2 Probe Operation Flexible configuration supports single-probe or dual-probe level sensing to fit any tank design.
🎯 5–100 kΩ Adjustable Sensitivity Fine-tune the probe response threshold to match different liquid conductivities and probe lengths.
⏱️ 0.1–10s Configurable Time Delay Prevents false operation from waves or splashing — delay on start, stop, or overrun depending on mode.
🛡️ Low-Voltage Electrodes Probes operate at max. AC 3.5V / <0.1mA — intrinsically safe and prevents electrolysis.
🔧 1×10⁷ Mechanical Life Outstanding durability with 1×10⁷ mechanical operations for demanding pump control cycling.

📋 Model & Ordering

Model Function Modes Probe Levels Sensitivity Time Delay Supply Datasheet
FCL18-02 Fill & Empty 6 (A–F) 1 or 2 probes 5–100 kΩ 0.1–10s 12–240V AC/DC 📄 Download PDF

💡 FCL18-02 is the multifunction version of the FCL18 liquid level relay series. It offers 6 selectable operating modes covering fill, empty, delayed fill/empty, and overrun timer for 1‑probe or 2‑probe configurations. For a simpler fixed‑function emptying relay, choose FCL18-01. Probe set FCL-PB is sold separately.

🔎 Operating Modes (A–F)

A: Fill (2 probes)
When liquid drops below S2, pump starts and fills until liquid reaches S1. Standard dual‑probe fill control.
B: Empty (2 probes)
When liquid reaches S1, pump starts and empties until liquid drops below S2. Standard dual‑probe drain control.
C: Delayed Fill (1 probe)
When liquid drops below S1, pump waits for delay T then fills until liquid reaches S1 again.
D: Delayed Empty (1 probe)
When liquid reaches S1, pump waits for delay T then empties until liquid drops below S1.
E: Fill with Overrun (1 probe)
When liquid drops below S1, pump starts immediately, then continues running for extra time T after reaching S1.
F: Empty with Overrun (1 probe)
When liquid reaches S1, pump starts immediately, then continues running for extra time T after dropping below S1.

⚙️ Technical Specifications

🔌 Supply

Supply TerminalsA1 – A2
Supply Voltage12–240V AC/DC
Power ConsumptionAC 3.5VA / DC 2.0W
Voltage Tolerance-15% ~ +10%

🛡️ Monitoring & Probes

Function6 modes: Fill, Empty, Delayed, Overrun
Probe TerminalsS1 – S2 – C (Common)
Probe Levels1 or 2 (mode dependent)
Sensitivity Range5 kΩ – 100 kΩ
Electrode Voltagemax. AC 3.5V
Probe Current< 0.1 mA
Time Delay (T)0.1–10s adjustable

🔌 Output

Contact1 × SPDT
Rated Current16A @ 250V AC
Mechanical Life1×10⁷ operations
Electrical Life1×10⁵ operations

📐 Physical & Environmental

Dimensions18 × 90 × 64 mm
MountingDIN rail EN 60715
Protection DegreeIP40 (front) / IP10 (terminals)
Operating Temp.-20°C ~ +55°C
Storage Temp.-30°C ~ +70°C

📜 Standards & Certifications

ComplianceGB/T 14048.5, IEC 60947-5-1, EN 6812-1
Contact ConfigurationSPDT: 11(COM)-12(NC)-14(NO)
Pollution Degree2
Max. Cable SizeAWG 13–20 / 0.4 N·m

💡 Panel LED Indicators

LED Color Status Meaning
Un Green OFF Supply voltage not applied
Un Green ON Supply voltage applied
R Red OFF NC (11-12) contact closed (pump off)
R Red ON NO (11-14) contact closed (pump on)

📈 Function Diagram – 6 Operating Modes

FCL18-02 Multifunction Liquid Level Relay Function Diagrams A–F

• The FCL18-02 supports 6 user‑selectable operating modes (A–F) for fill, empty, delayed, and overrun timer applications.
• Modes A and F use 2 probes (S1 + S2): pump starts at one level and stops at the other.
• Modes B, C, D, and E use 1 probe (S1 only): pump operation is controlled by a single level point with time delay or overrun timer.
• The time delay T (0.1–10s) can act as a delayed start (B, D) or as an overrun timer (C, F), depending on the selected mode.
• Sensitivity (5–100 kΩ) is adjustable to match the conductivity of the liquid and the probe length.

🎬 See it in Action

🔧 Wiring & Terminal Layout

Terminal Identification

A1 — Supply L / + A2 — Supply N / - S1 — Probe 1 (High Level) S2 — Probe 2 (Low Level) C — Common (Reference) 11 — COM 12 — NC 14 — NO
⚠️ Safety Note: Keep the power supply disconnected during installation. The probe circuit operates at low voltage (max. 3.5V AC) but must be wired with appropriate insulation. Do not connect probe terminals to mains voltage.

Supply (A1–A2): 12–240V AC/DC.
2‑probe modes (A, B): Connect both S1 and S2 plus the common C probe.
1‑probe modes (C, D, E, F): Connect S1 and C only. S2 can be left unconnected.
Output (11-12-14): SPDT 16A/250V AC, wire to pump contactor or valve.

FCL18-02 Wiring and Terminal Layout Diagram

🛠️ Parameter Setting Guide

  1. Enter Parameter Setting Mode: Long-press the button until the LED starts flashing.
  2. Select Function (A–F): Choose the desired operating mode from A through F based on your application (fill/empty, 1‑probe/2‑probe, delayed/overrun).
  3. Set Sensitivity (kΩ): Adjust the sensitivity threshold from 5 kΩ to 100 kΩ. Lower values for more conductive liquids; higher values for less conductive ones or longer probe cables.
  4. Set Time Delay T (if applicable): Configure the time delay from 0.1 to 10 seconds. In modes C and D this is a delayed start; in modes E and F this is an overrun timer. Modes A and B do not use the time delay.
  5. Confirm and Store: Long-press until LED stops flashing. Settings take effect immediately — no power cycle required.

🏭 Typical Applications

🏠 Water Tank Filling
Mode A or C: automatically fills overhead tanks — stops at high level, restarts at low level
💧 Sump & Sewage Drainage
Mode B or D: empties collection pits — starts at high level, stops at low level
🏭 Process Tank Management
Mode E/F with overrun timer ensures complete fill or drain beyond the probe point
🌧️ Stormwater Retention
Mode D with delayed empty prevents pump cycling during fluctuating water levels
🔧 Cooling Tower Level Control
Mode A maintains proper water level — starts makeup pump on low, stops on high
🚰 Well & Borehole Systems
Mode C with delayed fill prevents rapid pump cycling in deep well applications

🔗 Related Products

Explore other liquid level relays in the FCL18 series:

FCL18-01 — Single Function Empty FCL18-02 — Multifunction Fill & Empty (Current Page)

❓ Frequently Asked Questions

🔹 What is the difference between FCL18-01 and FCL18-02?
FCL18-01 is a single-function emptying relay (fixed 2-probe drain mode) with adjustable sensitivity only — no time delay, no mode selection. FCL18-02 is the multifunction version offering 6 selectable modes (A–F) covering fill, empty, delayed, and overrun operations for both 1-probe and 2-probe configurations, plus an adjustable time delay (0.1–10s).
🔹 How do I select the right operating mode (A–F)?
Choose based on your application: Mode A = fill with 2 probes (start on low, stop on high). Mode B = empty with 2 probes (start on high, stop on low). Mode C = delayed fill with 1 probe. Mode D = delayed empty with 1 probe. Mode E = fill with overrun timer (1 probe). Mode F = empty with overrun timer (1 probe).
🔹 What does the overrun timer do in modes E and F?
The overrun timer T keeps the pump running for an additional set time after the liquid level reaches the probe trigger point. In Mode E (Fill), the pump continues filling for T seconds after liquid reaches S1. In Mode F (Empty), the pump continues draining for T seconds after liquid drops below S1. This ensures complete filling or emptying beyond the probe position.
🔹 Can I use FCL18-02 with only one probe?
Yes. Modes C, D, E, and F are specifically designed for single-probe operation — connect only S1 and C. Modes A and B require two probes (S1, S2, and C). Select the mode that matches your probe configuration.
🔹 Are the probes safe to use in conductive liquids?
Absolutely. The probe circuit operates at a maximum of AC 3.5V with less than 0.1 mA. This is intrinsically safe for personnel and prevents electrolysis or corrosion of the electrodes over time.
🔹 What probes are compatible with FCL18-02?
Use the FCL-PB probe set (sold separately), available in lengths of 1.5m (red), 2.5m (white), or 3.5m (blue). Any standard conductive electrode set with up to three wires (S1, S2, C) can also be used.

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