⚠
warning Miller
Error Code L04
Thermocouple #4 Open — the fourth temperature sensor is not functioning or is disconnected.
? What Causes This
Open or disconnected temperature sensor, faulty thermocouple wiring.
✓ How to Fix It
- Check for open temperature sensor and repair.
- Change to back-up temperature sensor if available.
Source: page 55 of the official manual
From the manual
This error code appears in:
Miller ProHeat 35 Industrial Heater