HEX: 1A - Flame sensor short circuit

Fault Details:

The flame sensor has shorted to ground.

Recommended Solution:

Electrical check of flame monitor/ sensor. Inspect visually for damage to the unit, seal, thread, cable state, and connection pushed in and not damaged. Electrical continuity.

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