In many combi boilers, a diverter valve directs heated primary water either to the central-heating circuit or to the domestic-hot-water heat exchanger. When the valve sticks or its actuator fails, heating and hot-water performance can become inconsistent.
Common symptoms associated with diverter-valve faults
- Radiators warm up when only hot water is requested
- Hot water becomes lukewarm while heating works normally
- Heating behaviour changes when a tap is opened
- The valve actuator does not move correctly
- Switching between heating and hot water becomes intermittent
Why diagnosis is important
These symptoms can overlap with sensor, PCB, flow-system or heat-exchanger faults. A qualified technician should confirm the cause before replacing the valve or actuator to avoid unnecessary part replacement.
How to select the correct diverter valve
Identify the boiler brand and exact model, original valve or motor reference, hydraulic-body design, connector and actuator specification. Some repairs require only a motor or repair kit, while others require the complete valve assembly.
Boiler spare parts from Sanra Shop
Sanra Shop supplies diverter valves, 3-way valve motors, repair kits and other boiler spare parts for professional buyers. Share the boiler model and original part reference for compatibility assistance.
