How to Replace the Pcb Display on a Vaillant ecoTEC Plus 424 (UK)
Step-by-step UK guide to replacing the user interface / display board on a Vaillant ecoTEC Plus 424. Part numbers, torques, commissioning.
Vaillant
The part
Fit a new fascia display on Vaillant ecoTEC Plus 424 when the screen is blank, dim or the touch buttons no longer respond.
Isolate safely
The display board is separate from the main PCB on Vaillant ecoTEC Plus 424. It plugs in via a 6-way ribbon or JST connector.
Fit and commission
Handle by the edges — ESD damages the driver IC before you even fit it.
Recommission checklist
Refill the Vaillant ecoTEC Plus 424 to 1.2 bar cold. Bleed high-point radiators and the internal AAV.
Run a full flue-gas analysis after 15 minutes. Log the reading against the OEM commissioning envelope in the Benchmark book.
Frequently asked questions
- Do I re-enter installer settings?
- Yes — the display holds the language and clock; installer parameters live on the main PCB and persist.
- Is a firmware update needed?
- Only if the OEM display carries a newer part suffix (e.g. -02). Older firmware can throw comms faults with newer main PCBs.
- Do I need to notify the manufacturer?
- Only if the Vaillant ecoTEC Plus 424 is in warranty — Vaillant require log of any part swap for labour claims.
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