The Baxi 7661857 is a genuine OEM 3-way valve cartridge designed for use in selected Baxi, Main, and Potterton combi boilers. This hydraulic cartridge sits inside the diverter valve body and controls the flow of heated water between the central heating (CH) circuit and the domestic hot water (DHW) circuit.

When the cartridge becomes worn or blocked, the boiler may struggle to switch between heating and hot water, leading to fluctuating temperatures, radiators warming when taps run, decreased hot water flow, or diverter-related error codes. Replacing it with this genuine Baxi cartridge ensures smooth, accurate switching and restores reliable boiler performance.

Key Features:

• Genuine Baxi 3-way valve cartridge

• Restores correct switching between CH and DHW

• Resolves temperature fluctuations and crossover issues

• Designed for combi boilers requiring prioritised DHW

• Manufactured to strict Baxi OEM performance and durability standards

• Reliable, long-life mechanical design

• Direct-fit replacement for quick professional installation

Compatibility

The Baxi 7661857 3-Way Valve Cartridge is compatible with selected models across:

• Baxi Combi boilers

• Main boilers

• Potterton boilers

Typical compatible ranges include (varies by model):

• Baxi Combi / Combi HE

• Main Combi Eco / Eco Elite

• Potterton Promax Combi

Any appliance listing 7661857 in its official parts manual will accept this cartridge.

Engineers should always confirm exact compatibility using the boiler’s service manual or parts list.