UK trade guideBoiler Spares 5 min readUpdated 11 July 2026

How to Replace the Diverter Valve on a Viessmann Vitodens 200-W 32 (UK)

Step-by-step UK guide to replacing the 3-way diverter valve on a Viessmann Vitodens 200-W 32. Part numbers, torques, commissioning.

Viessmann

The part

Replace the diverter valve on Viessmann Vitodens 200-W 32 when hot water runs cold on demand or the boiler cycles between CH and DHW.

Isolate safely

Drain to below the diverter body via the CH drain-off. On Viessmann Vitodens 200-W 32 the diverter is a cartridge design — pull the retaining clip and lift out.

Fit and commission

Fit new O-rings, silicone-grease the cartridge and align the actuator drive slot before refitting the motor.

Recommission checklist

Refill the Viessmann Vitodens 200-W 32 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

Actuator or cartridge only?
Diagnose first: manually push the actuator pin. If it moves freely, replace the actuator only; if the pin sticks, the cartridge is scaled.
Any special tools?
A brass spanner or the OEM diverter tool avoids cracking the plastic body on Viessmann Vitodens 200-W 32.
Do I need to notify the manufacturer?
Only if the Viessmann Vitodens 200-W 32 is in warranty — Viessmann require log of any part swap for labour claims.
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