HEX: 1B - Overheat sensor short circuit

Fault Details:

The overheat sensor has a short circuit to ground.

Recommended Solution:

Electrical check of the overheating sensor. Inspect visually for damage to the unit, seal, thread, cable state, and connection pushed in and not damaged. Electrical continuity. Ensure no debris is tucked on top or sides of the sensor. Do not use compressed air to clean debris.

Note, different models and controllers might have different fault code meanings. If you're not sure, you can contact Heatso directly.