1. Introduction
The Finglai ETC-974 is a versatile microcomputer temperature controller designed for refrigeration, defrosting, and fan control applications. It features dual NTC sensors for precise temperature monitoring and includes alarm functions for temperature overrange and sensor faults. This manual provides detailed instructions for the safe and efficient installation, operation, and maintenance of your ETC-974 controller.
2. Product Overview
The ETC-974 controller features a clear digital display and intuitive control buttons for easy programming and monitoring. Its compact design allows for panel mounting in various industrial and commercial refrigeration units.
Figure 2.1: Perspective view of the ETC-974 Temperature Controller, showing the front panel and side mounting clips.
Figure 2.2: Front view of the ETC-974 Temperature Controller, highlighting the digital display and control buttons (Up, Down, FNC, SET).
Figure 2.3: Side view of the ETC-974 Temperature Controller, showing the orange mounting clips for secure installation.
Figure 2.4: Bottom view of the ETC-974 Temperature Controller, showing the terminal block for electrical connections.
3. Specifications
| Feature | Specification |
|---|---|
| Model Number | ETC-974 |
| Measure Range | -50 to 120 °C (-58 to 248 °F) |
| Resolution | 0.1°C |
| Accuracy | NTC: ±0.5°C (-30°C to 50°C), others: ±1 °C |
| Supply Voltage Options | 220VAC, 110VAC (50/60Hz), or 12-24VAC/DC (Note: One option per unit) |
| Power Consumption | Less than 5W |
| Output Types | 3 Mechanical Relays (Compressor, Fan, Defrosting) |
| Compressor Relay Contact Rating | 10A at 220VAC |
| Fan Relay Contact Rating | 10A at 220VAC |
| Defrost Relay Contact Rating | 10A at 220VAC |
| Input Types | 2 NTC sensors (2m cable, included) |
| Panel Size | 77mm x 32mm |
| External Dimensions | 77mm x 32mm x 58mm |
| Perforation Dimensions | 71mm x 29mm |
| Control Method | ON/OFF Control |
| Setting Method | Touch Switch |
| Indication Method | Three-digit LED + Minus digit + Status indicator light (set; refrigeration; defrost; fan) |
| Front Panel IP Rating | IP65 |
| Operating Temperature | -5 to 55 °C (23 to 131 °F) |
| Operating Humidity | 10% to 90% RH, non-condensing |
| Storage Temperature | -25 to 75 °C (-13 to 167 °F) |
| Display Type | DIGITAL |
| Use | Industrial |
| Display Size | 2.0 - 3.9 Inches |
4. Installation and Wiring
Safety Warning: Installation should only be performed by qualified personnel. Ensure all power is disconnected before attempting any wiring to prevent electric shock or damage to the unit.
4.1 Mounting
The ETC-974 is designed for panel mounting. Create a rectangular cutout in your panel with the following dimensions:
- Length: 71mm
- Width: 29mm
Insert the controller into the cutout and secure it using the orange mounting clips on the sides of the unit.
4.2 Wiring Diagram
Refer to the wiring diagram below for proper electrical connections. Ensure that the power supply matches the voltage rating of your specific ETC-974 unit (220VAC, 110VAC, or 12-24VAC/DC).
Figure 4.1: Detailed wiring diagram for the ETC-974 Temperature Controller. This diagram illustrates connections for power supply, compressor, fan, defrost, and sensors.
Terminal Connections:
- Terminals 1 & 2: Power Supply Input (Line)
- Terminals 3 & 4: Compressor Output (Rated 10A at 250V)
- Terminals 5 & 6: Fan Output (Rated 10A at 250V)
- Terminals 7 & 8: Defrost Output (Rated 10A at 250V)
- Terminals 9 & 10: NTC Sensor Inputs (Pb1, Pb2)
Connect the two NTC temperature sensors (included) to terminals 9 and 10. Ensure all connections are secure and properly insulated.
5. Operation
The ETC-974 controller is operated using the four buttons on the front panel: Up arrow (∧), Down arrow (∨), FNC (Function), and SET.
5.1 Button Functions
- ∧ (Up Arrow): Increases values, navigates up in menus.
- ∨ (Down Arrow): Decreases values, navigates down in menus.
- FNC (Function): Exits current setting mode, accesses advanced functions (long press).
- SET: Enters setting mode, confirms selection.
5.2 Basic Temperature Setting
To set the desired temperature:
- Press the SET button once. The current set temperature will flash on the display.
- Use the ∧ or ∨ buttons to adjust the temperature to your desired value.
- Press the SET button again to confirm and save the new setting.
5.3 Status Indicators
The LED display includes status indicators for:
- SET: Indicates the controller is in setting mode.
- Refrigeration: Indicates the compressor is active.
- Defrost: Indicates the defrost cycle is active.
- Fan: Indicates the fan is active.
For detailed programming of defrost cycles, fan operation, and alarm parameters, please refer to the comprehensive PDF manual linked in the "Warranty and Support" section.
6. Maintenance
To ensure optimal performance and longevity of your ETC-974 temperature controller, follow these maintenance guidelines:
- Cleaning: Regularly wipe the front panel with a soft, dry cloth. Avoid using abrasive cleaners or solvents that could damage the display or buttons.
- Sensor Inspection: Periodically check the NTC sensors and their cables for any signs of damage, corrosion, or loose connections. Ensure they are securely placed in their intended monitoring locations.
- Ventilation: Ensure that the controller's housing has adequate ventilation to prevent overheating. Do not obstruct any vents.
- Power Supply: Verify that the power supply voltage remains stable and within the specified range for your unit.
7. Troubleshooting
If you encounter issues with your ETC-974 controller, refer to the following common troubleshooting steps:
| Problem | Possible Cause | Solution |
|---|---|---|
| Display is blank or unit is unresponsive. | No power supply or incorrect voltage. | Check power connections and ensure the supply voltage matches the unit's requirements. Verify circuit breaker or fuse. |
| Temperature reading is inaccurate or erratic. | Faulty or improperly connected NTC sensor. | Check sensor wiring for loose connections or damage. Replace sensor if necessary. Ensure sensors are correctly positioned. |
| Compressor/Fan/Defrost not activating. | Incorrect temperature settings, relay failure, or wiring issue. | Verify set temperature and differential settings. Check wiring to the respective loads. If relays are suspected, professional inspection is recommended. |
| Alarm continuously active. | Temperature outside set limits or sensor fault. | Check the actual temperature against the alarm set points. Inspect sensors for faults. Refer to the full manual for specific alarm codes if displayed. |
7.1 User Tips
- For optimal performance, ensure the NTC sensors are placed in locations that accurately represent the temperature you wish to control, away from direct airflow or heat sources that could cause false readings.
- When setting temperature differentials, consider the application to prevent rapid cycling of the compressor, which can reduce its lifespan.
- Always double-check wiring connections, especially for power and load outputs, to prevent damage to the controller or connected equipment.
8. Warranty and Support
For comprehensive details regarding warranty, advanced programming, and further technical support, please refer to the official product manual:
Download ETC-974 Defrost Temperature Controller Manual (PDF)
You can also visit the Finglai Electric store for additional product information and support.