Verified boiler fault code
Vaillant F.70 Fault Code (ecoTEC plus/pro (manual models))
No valid DSN in the display and/or mainboard.
Safety disclaimer
Fault code summary
- Manufacturer
- Vaillant
- Fault code
- F.70
- Fault type
- PCB/electronics
- Severity
- Not specified
- Reset
- Not specified
- Applicable models
- ecoTEC plus 612, ecoTEC plus 615, ecoTEC plus 618, ecoTEC plus 624, ecoTEC plus 630, ecoTEC plus 637, ecoTEC plus 824, ecoTEC plus 831, ecoTEC plus 837, ecoTEC pro 28
Quick answer
No valid DSN in the display and/or mainboard.
What does this fault code mean?
No valid DSN in the display and/or mainboard.
Common causes
- Display and mainboard replaced at the same time without the device-specific number being adjusted.
Symptoms
This information was not provided in the verified manufacturer source.
What can the homeowner safely check?
This information was not provided in the verified manufacturer source.
Boiler reset information
Reset information was not provided in the verified manufacturer source. Do not repeatedly reset an unresolved fault.
When should I call an engineer?
Contact a suitably qualified heating engineer when the fault persists, the boiler locks out, or the manufacturer instructions do not resolve it. For gas appliance work in the UK, use a Gas Safe registered engineer.
Engineer diagnosis
- Check product coding and the relationship between display and mainboard.
Applicable boiler models
Related fault codes
- F.22 — ecoTEC plus/pro (manual models)
Dry fire.
Read fault code - F.23 — ecoTEC plus/pro (manual models)
Water shortage; the temperature difference between flow and return NTC is too large.
Read fault code - F.24 — ecoTEC plus/pro (manual models)
Water shortage; temperature rise too quick.
Read fault code - F.25 — ecoTEC plus/pro (manual models)
Interruption in the compact thermal module cable harness.
Read fault code - F.28 — ecoTEC plus/pro (manual models)
The appliance does not start: attempts to ignite during start failed.
Read fault code - F.29 — ecoTEC plus/pro (manual models)
The flame goes off during operation and subsequent ignition attempts fail.
Read fault code - F.32 — ecoTEC plus/pro (manual models)
Fan speed variation.
Read fault code - F.49 — ecoTEC plus/pro (manual models)
eBUS undervoltage.
Read fault code
Manufacturer documentation
Instructions for installation and servicing ecoTECF.70 | No valid DSN in display and/or mainboard | Spare part failure display and mainboard interchanged at same time and device specific number not adjusted
Last verified
2026-09-12
Frequently asked questions
What does Vaillant F.70 mean?
No valid DSN in the display and/or mainboard.