UK trade guideBoiler Spares 6 min readUpdated 9 July 2026

How to Replace a Vaillant ecoTEC Diverter Valve (UK)

Full diverter assembly swap on Vaillant ecoTEC plus/pro. OEM 0020132682, motor head 178984.

Vaillant

Two parts to fail

Vaillant diverters have two failure modes: the cartridge (mechanical, 0020132682) or the motor head (electrical, 178984). Swap the motor first — often solves stuck DHW.

OEM parts

  • Full assembly — 0020132682.
  • Motor head only — 178984.
  • Cartridge only — 178985.
  • O-ring kit — 0020017181.

Fit

Isolate at service valves. 15 mm socket for motor head, T25 Torx for cartridge clip. Refit with grease on all EPDM O-rings.

Frequently asked questions

Does the diverter code need clearing?
No — Vaillant ecoTEC auto-clears on 3 successful cycles.
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