Vaillant ecoTEC plus Fault Codes
The Vaillant ecoTEC plus is one of the two or three most installed boilers in Britain — a premium German-engineered combi, system and open-vent range that has anchored Vaillant's line-up for well over a decade. Its fault language is the famous F-code system: F.22 for low water pressure, F.28 and F.29 for ignition and flame loss, F.75 for the pump/pressure-sensor fault that virtually every ecoTEC owner eventually googles. Vaillant's codes are precise and stable across model years, which makes them unusually useful: the same F.28 means the same thing on a 2012 ecoTEC plus as a 2023 one. The display also offers a diagnostic mode engineers use to read live data, so the code you note down connects directly to a well-mapped diagnostic path. Below are the codes ecoTEC plus owners actually meet, each linked to its full cause-and-fix page.
Where ecoTEC plus fault codes appear
The ecoTEC plus has a backlit digital display with Vaillant's DIA system: normal running shows temperature and status symbols, and a fault shows as "F." plus a number, often with a wrench or flame-cross symbol. The code persists on screen until cleared, so there is no race to note it — but do record the exact number; F.28 and F.29 (ignition failure versus flame loss in operation) are different diagnoses.
Resetting a Vaillant ecoTEC plus
Press the reset button — marked with a crossed-out flame — for around a second; the boiler clears the lockout and retries. F.22 (low pressure) wants the system topped up to 1–1.5 bar via the filling loop first, watching the pressure on the display. Vaillant limits consecutive resets on ignition faults by design; if the code returns, that is your answer, not an invitation to keep pressing.
Common ecoTEC plus problems
The ecoTEC plus's best-known faults are well documented: F.75 (the pressure sensor failing to see the pump start — the range's signature fault, usually pump or sensor), F.22 pressure loss, the F.28/F.29 ignition pair, and F.27 flame simulation. The aluminium heat exchanger rewards clean system water — magnetic filters and inhibitor genuinely matter on this range — and condensate freezing produces its share of winter F.28s.
Most common ecoTEC plus fault codes
- F.75 No pressure change detected when the pump starts — typically a faulty pump or water… Read more →
- F.22 F.22 is a low water pressure (system protection) fault. Your Vaillant boiler has detected… Read more →
- F.28 F.28 is an ignition lockout fault. Your Vaillant boiler ran through its normal start-up… Read more →
- F.29 F.29 is a flame-failure lockout. It means your Vaillant boiler successfully lit but then… Read more →
- F.27 The F.27 code appears on Vaillant ecoTEC Pro and Plus boilers when the boiler's control… Read more →
- F.61 The F.61 code on a Vaillant boiler signals a gas valve control or communication fault. In… Read more →
- F.62 The F.62 code is a combustion safety fault. It appears when your Vaillant boiler detects… Read more →
- F.83 The F.83 code on a Vaillant boiler indicates that after the burner has ignited, the flow… Read more →