CodeRegistry
Brands
  1. Home
  2. Vaillant
  3. ecoTEC plus Boilers
  4. F.70
About·Privacy·Terms

CodeRegistry — Your global library for technical solutions.

For your safety: always follow the equipment manufacturer’s official manuals. CodeRegistry is an independent help site and is not affiliated with the brands listed here.

F.70

F.70 - Invalid Device Specific Number (DSN)

Vaillant · ecoTEC plus Boilers

What does F.70 mean?

This fault typically occurs after replacement parts have been installed, specifically if both the display and the Printed Circuit Board (PCB) were replaced simultaneously without resetting the Device Specific Number.

Common Causes

  • Display and PCB replaced at the same time and DSN was not reset.
  • Incorrect or missing output range coding resistance.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Press the reset button on the boiler display up to three times to try and clear the fault.

  2. 2

    This fault usually occurs after spare parts (display and PCB) have been replaced by a technician.

  3. 3

    Contact the installer or customer service to ensure the Device Specific Number (DSN) is reset and the correct output range coding resistance is fitted.

Browse all codes in this manual (146)
Verified technical data. Last updated: April 2026

Related Faults

Communication fault (display/PCB)Communication fault - No communication with the PCBD.092 = 1D.092 = 1 — actoSTOR module connection errorF.0F.0 — Flow–NTC open circuit
Source: Vaillant ecoTEC plus Boilers
Open Manual (Page 47)Search more codes in this manual