Differential control for simple solar systems
The SOREL STDC compares temperatures to control a simple solar-thermal, storage or solid-fuel boiler arrangement. The manufacturer lists nine hydraulic applications. The selected application must match the actual pipework and sensors; the number of applications does not mean nine independent circuits can run together.
Check the controller version and pump first
SOREL offers STDC variants with different pump speed-control arrangements. Before ordering a replacement, send the controller's version label, pump model, sensor details and hydraulic diagram. Match the pump's control interface to the exact version's installation manual rather than assuming every STDC has the same outputs.
The current manufacturer table lists three PT1000 sensor inputs, one 230 V relay output and one PWM or 0–10 V control output. It does not list a volt-free relay output. The manuals below cover versions 1–4; use the wiring diagram for the unit actually supplied.
Functions and limitations
The documented functions include setup assistance, temperature protection and recorded operating information. The manufacturer does not list CAN connectivity, Ethernet or microSD logging for STDC. Do not select it on the assumption that it provides remote monitoring.
For heating-circuit control with a mixer, see the SOREL MHCC heating controller. For related solar equipment, browse solar hot-water systems.
Manuals and quotation
Select the installation manual by language and hardware version. There is no Greek manual among these six existing files. Check the hardware version before following an instruction. Send your system diagram, existing controller label and pump details for technical selection and a quotation.
Technical table
| Specification | Value |
|---|---|
| Sensor inputs PT1000 | 3 |
| Relay outputs 230V | 1 |
| Relay output voltage-free | ✕ |
| Outputs 0..10V or PWM signal for speed control of high-efficiency pumps | 1 |
| Number of applications | 9 |
| Extension of pre-defined systems by selectable additional functions | ✕ |
| LEDs red/green for display of operating status | ✕ |
| Statistics and graphic analysis of data memory | ✓ |
| Flow based heat metering via Grundfos direct sensor (VFS / VVX) | ✕ |
| Pressure monitoring via Grundfos direct sensor (RPS) | ✕ |
| Battery-backed Real Time Clock > 24h | ✓ |
| Time and Temperature-controlled thermostat function | ✓ |
| Legionella function via solar | ✓ |
| Legionella protecion via additional heating | ✓ |
| Cooling function | ✓ |
| Setup wizard | ✓ |
| System protection | ✓ |
| Collector protection | ✓ |
| Storage protection (CP Tmax) | ✓ |
| Anti-freeze protection | ✓ |
| Recooling | ✓ |
| Start logic for vacuum tube collectors | ✓ |
| Control program for self-dumping systems (drain-back) | ✓ |
| Function control and error memory with date and time | ✓ |
| Menu blocker | ✓ |
| Power supply for universal voltage range (100…240VAC) and reduced standby consumption | ✕ |
| CAN bus connection for SOREL Connect | ✕ |
| Data logging on microSD card | ✕ |
| Ethernet connection | ✕ |
| Dimensions Height x Width x Depth in mm | 115 x 86 x 45 |
| Housing colour | RAL 9003 |
| Protection Class | IP40 |
| Mounting Hardware, Spare Fuse and User Manual | ✓ |
Technical documents (6)
For an accurate quote, send us
- Where the product will be used
- Quantity or dimensions where available
- Photos, drawings or material list if available
- Whether you need store collection or delivery
- Photo or drawing of the existing controller/control panel
- System type: solar, boiler, buffer or combined setup
- Number of sensors and pumps to be controlled
- Existing controller model, if replacing an old unit