How to Reset Error 01 and Error 04 on WES E-Compact, Trianco Greenflame, Bioflame, and Greenflame Boilers

June 05 2025 , 5 min reading time

Facing Error 01 or 04 on your biomass boiler? This guide walks you through resetting the high limit stats, checking the pump, and ensuring safe boiler restart.

How to Reset Error 01 and Error 04 on WES E-Compact, Trianco Greenflame, Bioflame, and Greenflame Boilers

If your WES E-Compact, Trianco Greenflame, Bioflame, or Greenflame boiler displays Error 01 (Er01) or Error 04 (Er04), this guide will help you troubleshoot and reset the system safely.

Understanding the Errors

Error Code: Er01 – Safety Thermostat Activation

✅ Issue: High temperature detected, triggering a safety shutdown.
✅ Common Causes:

Water overheating due to a pump or valve failure preventing hot water circulation.
A power cut stopping pumps or valves from operating.
Low water pressure, causing air pockets in the heat exchanger to overheat.

Error Code: Er04 – Water Over Temperature

✅ Issue: Boiler detected excessive water temperature.
✅ Common Causes:

Same as Er01 – pump/valve failure, power cuts, or low water pressure.

Step-by-Step Guide to Resetting the Errors

🛑 Important: Before commencing any work, isolate the power to the boiler.

1. Reset the Safety Temperature Limiter (STL)

The boiler has two high limit stats that could be activated during an overheating event. You must reset both before restarting the system.

First High Limit Stat (Front of the Boiler)

Located on the front of the boiler, usually to the left or right of the display.
Covered by a small, circular black cap – twist it anti-clockwise to reveal a white button.
Press the white button using a small tool (screwdriver or nail). Do not use your finger.
The button should ping back out – this is normal.
Note: You can only reset this if the boiler temperature is below 80°C. If not, wait for it to cool down.

Second High Limit Stat (Often behind the First)

Found by lifting the front boiler lid and pulling back the grey insulation pad.
It may be hard to see – use a torch to locate it.
Reset it the same way as the first stat.

2. Test the Boiler Pump

If the issue was caused by overheating, it’s important to check that the boiler pump is working:

Remove the error on the display until it shows ‘OFF’.
Press and hold ‘ESC’ until ‘Pump Test’ appears.
Locate the pump (usually near the boiler) and feel if it is spinning.
If the pump isn’t spinning, it may need to be replaced.

3. Clear the Error on the Display and Restart the Boiler

After resetting both high limit stats:

Check water pressure – it should be at least 1 bar.
Purge air from the system: Open the cap of the air release valve under the boiler lid.
Clear the error message on the boiler display.
Clean the burner grate and then restart the boiler.

What to Do if the Error Happens Again

🚨 If your boiler enters Error 01 or Error 04 repeatedly, consider these possibilities:
✔️ A power cut may have caused the issue. Simply clean out the burner grate and restart the boiler.
✔️ If the error reoccurs without a power cut, your boiler may require professional repair.

🔧 Need an Engineer?
Contact the manufacturer approved service provider, such as Tisigo Boiler Engineers, to ensure your system is functioning properly.

Key Takeaways

✔️ Error 01 and 04 indicate overheating, usually due to pump or valve issues.
✔️ Reset both high limit stats before restarting the boiler.
✔️ Ensure water pressure is at least 1 bar and all air is purged.
✔️ Test the boiler pump to confirm it’s working.
✔️ If errors persist, seek professional help.