1. Introduction
The GEYA GRL8 series liquid level control relays are designed for precise monitoring and control of liquid levels in various applications. These devices are ideal for managing water levels in wells, basins, reservoirs, and tanks, ensuring efficient operation of pumps for filling or emptying. The GRL8 series offers robust performance with flexible configuration options to suit diverse industrial and domestic needs.
2. Key Features
- Model GRL8-01: Provides 2-level control mode.
- Model GRL8-02: Offers 2 or 1 level control mode, providing greater flexibility.
- Function Selection: User-selectable PUMP UP (filling) or PUMP DOWN (emptying) functions.
- Adjustable Time Delay: Output time delay adjustable from 0.1 to 10 seconds.
- Adjustable Sensitivity: Sensitivity (input resistance) can be adjusted via a potentiometer from 5 kΩ to 100 kΩ.
- Wide Supply Voltage: Galvanically separated supply voltage AC/DC 24-240V.
- Output Contact: 1 SPDT (Single Pole Double Throw) output with a rating of 10A/AC1.
- Status Indication: Relay status is clearly indicated by an LED.
- Mounting: Compact 1-MODULE design for DIN rail mounting.
3. Technical Specifications
Refer to the table below for detailed technical parameters of the GRL8 series relays:
Image: Technical Parameters for GRL8-01 and GRL8-02 models.
| Parameter | GRL8-01 (2 level control mode) | GRL8-02 (2 or 1 level control mode) |
|---|---|---|
| Function | 2 level control mode | 2 or 1 level control mode |
| Supply terminals | A1-A2 | A1-A2 |
| Voltage range | AC/DC 24-240V (50-60Hz) | AC/DC 24-240V (50-60Hz) |
| Input | max. 2VA | max. 2VA |
| Supply voltage tolerance | -15%; +10% | -15%; +10% |
| Sensitivity (input resistance) | adjustable in range 5 kΩ - 100 kΩ | adjustable in range 5 kΩ - 100 kΩ |
| Voltage in electrodes | max. AC 5V | max. AC 5V |
| Current in probe | AC < 0.1 mA | AC < 0.1 mA |
| Time response | max. 400 ms | max. 400 ms |
| Max. capacity length | 800 m (sensitivity 25kΩ), 200 m (sensitivity 100 kΩ) | 800 m (sensitivity 25kΩ), 200 m (sensitivity 100 kΩ) |
| Max. capacity of probe cable | 400 nF (sensitivity 25kΩ), 100 nF (sensitivity 100 kΩ) | 400 nF (sensitivity 25kΩ), 100 nF (sensitivity 100 kΩ) |
| Time delay (t) | adjustable, 0.1 - 10 s | adjustable, 0.1 - 10 s |
| Accuracy in setting (mechanical) | ± 10% | ± 10% |
| Temperature coefficient | 0.05%/°C, at +20°C (0.05°F, at =68°F) | 0.05%/°C, at +20°C (0.05°F, at =68°F) |
| Output indication | red LED | red LED |
| Mechanical life | 1×10⁷ | 1×10⁷ |
| Electrical life (AC1) | 1×10⁵ | 1×10⁵ |
| Reset time | max. 200ms | max. 200ms |
| Operating temperature | -20°C to +55°C (-4°F to 131°F) | -20°C to +55°C (-4°F to 131°F) |
| Storage temperature | -35°C to +75°C (-22°F to 158°F) | -35°C to +75°C (-22°F to 158°F) |
| Mounting/DIN rail | Din rail EN/IEC 60715 | Din rail EN/IEC 60715 |
| Protection degree | IP40 for front panel/IP20 terminals | IP40 for front panel/IP20 terminals |
| Operating position | any | any |
| Overvoltage category | III. | III. |
| Pollution degree | 2 | 2 |
| Max. cable size(mm²) | solid wire max. 1×2.5 or 2×1.5/ with sleeve max. 1×2.5 (AWG 12) | solid wire max. 1×2.5 or 2×1.5/ with sleeve max. 1×2.5 (AWG 12) |
| Dimensions | 90×18×64mm | 90×18×64mm |
Note: Specifications are subject to change without prior notice.
Dimensions
Image: Physical dimensions of the GRL8 series relay in millimeters.
4. Product Overview
The GRL8 series relays are designed for easy integration into control panels. Below are diagrams illustrating the main components and their functions.
GRL8-01 Function Diagram
Image: Labeled components for GRL8-01, including Supply Voltage Terminals (A1, A2), Max/Min Level Sensor connections, Supply Indication (GREEN), Relay Status Indication (RED), Sensitivity Setting, Model No., Level Monitoring Circuit Terminal (C, 11, 12, 14), and Output Contact.
GRL8-02 Function Diagram
Image: Labeled components for GRL8-02, similar to GRL8-01 but also showing the PUMP UP or DOWN function selector.
5. Installation & Wiring
The GRL8 relays are designed for DIN rail mounting. Ensure all power is disconnected before installation and wiring. Follow local electrical codes and safety regulations.
Wiring Diagram
Image: Detailed wiring diagram showing connections for power supply (Un), level sensors (Max, Min, C), and output contacts (11, 12, 14). Also includes panel layout and function diagrams.
Sensor Connections:
- Connect the Common Probe (C) to the lowest point of liquid detection.
- Connect the Min Level Probe (Min) for the minimum liquid level.
- Connect the Max Level Probe (Max) for the maximum liquid level.
- Ensure probes are securely installed and insulated from each other, except through the liquid.
Output Connections:
- The relay has a 1SPDT output. Terminals 11, 12, and 14 are available.
- Terminal 11 is the Common contact.
- Terminal 12 is Normally Closed (NC).
- Terminal 14 is Normally Open (NO).
- Connect your pump or control device to the appropriate contacts (e.g., 11 and 14 for pump activation when liquid level changes).
6. Operation
The GRL8 series relays can be configured for two primary operation modes: PUMP UP (filling) and PUMP DOWN (emptying).
Operation Modes Explained
- PUMP UP (Filling Mode): The pump activates when the liquid level drops below the 'Min' probe and deactivates when it reaches the 'Max' probe. This mode is used to fill a tank.
- PUMP DOWN (Emptying Mode): The pump activates when the liquid level reaches the 'Max' probe and deactivates when it drops below the 'Min' probe. This mode is used to empty a tank.
Adjustments:
- Sensitivity: Use the 'Sensitivity' potentiometer to adjust the input resistance (5-100K) based on the conductivity of the liquid and the length of the sensor cables.
- Time Delay (Tt): Use the 'Tt' potentiometer to set a time delay (0.1-10s) for the output. This prevents rapid switching due to minor liquid fluctuations.
Visual Demonstration
Video: Demonstration of the GRL8 relay controlling liquid levels for both pump down and pump up scenarios.
7. User Tips
- Sensor Cable Extension: Sensors can typically be extended. Users have reported successful extensions up to 10 meters using standard twisted pair cables. For longer distances or specific environments, consult the technical specifications for maximum capacity length and probe cable capacity.
- Direct Pump Connection: For pumps up to 2kW (10A at 220V), direct connection to the relay's output contacts (11/12 or 11/14) is generally possible without an additional contactor. Always verify the pump's power requirements against the relay's maximum contact load.
- Sensor Mounting: Sensors can be simply suspended at the desired maximum, minimum, and common liquid levels within the tank or container. Ensure they are stable and do not move freely.
- Normal Operation Sound: It is normal to hear a faint clicking sound from the relay when it switches on or off, indicating proper operation of the internal mechanism.
- Filling vs. Draining: When setting up, ensure you correctly select the 'PUMP UP' (filling) or 'PUMP DOWN' (draining) mode based on your application to prevent unintended pump behavior.
8. Troubleshooting
- Relay Not Activating:
- Check power supply to terminals A1 and A2.
- Verify sensor connections to Max, Min, and C terminals.
- Ensure liquid level is within the detection range of the probes.
- Adjust 'Sensitivity' potentiometer, especially for liquids with low conductivity or long sensor cables.
- Check the 'Time Delay (Tt)' setting; a long delay might cause perceived non-activation.
- Pump Not Responding to Relay:
- Confirm correct wiring of the pump to the output contacts (11, 12, 14).
- Measure voltage at the output contacts (e.g., between 11 and 14 when activated) to ensure the relay is providing power. If voltage is low (e.g., 0-0.3V), there might be an internal fault or incorrect wiring.
- Ensure the pump's power rating does not exceed the relay's 10A/AC1 contact rating. For higher power pumps, an external contactor is required.
- Erratic Operation:
- Check for loose sensor connections or damaged sensor cables.
- Ensure probes are clean and free from deposits that might affect conductivity.
- Adjust sensitivity to match liquid properties.
- Increase time delay if rapid liquid fluctuations are causing frequent switching.
9. Maintenance
- Sensor Cleaning: Periodically inspect and clean the liquid level sensors, especially in environments prone to mineral deposits, sludge, or other contaminants (e.g., septic tanks). Buildup on the probes can interfere with accurate level detection.
- Connection Checks: Regularly check all electrical connections for tightness and signs of corrosion or damage.
- Environmental Conditions: Ensure the relay is operating within its specified temperature and protection degree (IP40 for front panel/IP20 terminals) to prolong its lifespan.
10. Warranty and Support
GEYA products are manufactured to high-quality standards. For any technical assistance, warranty claims, or support inquiries, please contact your authorized GEYA distributor or the GEYA Official Store. Please have your product model number and purchase details ready when contacting support.
