For , wire the load (e.g., a contactor coil) in series through the Normally Open (NO) and Common (COM) terminals.
To enter the full configuration menu, press and hold the button for 3 to 5 seconds. 4. Parameter Configuration
Connect your external contactor loop across Terminal 3 (Normally Open) and Terminal 4 (Common) . fourtech temperature controller manual
Simply search for your specific boiler model on these sites. The official manual covers everything from initial setup and temperature adjustments to detailed troubleshooting and safety feature explanations.
The output relay or solid-state relay has likely failed closed (fused together), constantly feeding power to your heater. Disconnect the main power immediately to prevent a thermal runaway event. To help find specific answers for your system, tell me: For , wire the load (e
What (SSR, Relay contactor, or analog valve) are you operating? Share public link
Look for an "AT" parameter in the menu. Engaging this allows the controller to "learn" your system's heating/cooling curves for more precise regulation. Installation Best Practices The output relay or solid-state relay has likely
| Error Code | Meaning & Common Fix | | :--- | :--- | | | Failure to ignite. Press the R button for at least 2 seconds to reset. | | E02 | Safety thermostat triggered (overheating). Press the R button for at least 2 seconds to reset after the boiler cools down. | | E03 | Draught/pressure switch tripped or flue fault. Check the flue for obstructions. | | E04 | No flame after six reset attempts. Further professional investigation is needed. | | E05 | Heating circuit temperature sensor defective (open/short circuit). The sensor needs replacement. | | E25 / E26 | No water circulation, possibly a pump blockage. Check the pump. | | E32 | Scale in the heat exchanger. Professional cleaning is required. | | E35 | Parasitic flame error. Press the R button for at least 2 seconds to reset. |
| Problem | Likely Cause | Solution | | :--- | :--- | :--- | | | Sensor is shorted or temperature too high | Check thermocouple wires for a short. | | Display shows LLL | Sensor is broken or reversed polarity | Swap the two sensor wires. | | Temperature swings wildly | PID not tuned | Run Auto-Tuning (AT=1). | | Unit won't heat at all | Output relay failed or wiring loose | Check terminals 7 & 8 for voltage during heat demand. | | Display flashes 5C.Er | Sensor type mismatch | Check that the input type (e.g., K ) matches your probe. |
Instead of relying on trial-and-error, which can be time-consuming and dangerous, the technician can reference the manual to isolate the fault. For example, if a display reads "HHHH" or "EEEE," the manual clarifies whether the issue lies with a broken sensor or an internal hardware failure. This diagnostic capability minimizes downtime and reduces the operational costs associated with prolonged production halts.
This guide simplifies the technical jargon to help you get your device up and running efficiently. 1. Understanding the Faceplate