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F.65

F.65 — Electronics temperature too high

Vaillant · ecoTEC plus Boilers

What does F.65 mean?

The temperature of the boiler's electronic components has become too high. This could be due to external heat effects or a defect within the electronics itself.

Common Causes

  • Electronics too hot due to external effect (e.g., poor ventilation, external heat source).
  • Electronics defective.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Ensure the boiler area has adequate ventilation and is not obstructed by objects.

  2. 2

    Check for any external heat sources near the boiler that might be causing it to overheat.

  3. 3

    If the error persists, contact a qualified service technician as this may indicate a fault with the internal electronics.

Browse all codes in this manual (100)
Verified technical data. Last updated: April 2026

Related Faults

F.0F.0 — Flow–NTC open circuitF.1F.1 — Return–NTC open circuitF.10F.10 — Flow NTC short circuit
Source: Vaillant ecoTEC plus Boilers
Open Manual (Page 43)Search more codes in this manual