Vaillant Ecotec Plus 831 Diverter Valve Replacement 0020020015

This Vaillant Ecotec Plus 831 diverter valve 0020020015 controls the switch between central heating and hot water in compatible ecoTEC boilers. If the valve is sticking or worn you may notice hot water going warm/cold, heating and hot water not switching correctly, radiators warming when a tap runs, or unstable temperature/flow. Replacing with the correct diverter valve restores proper changeover and helps reduce repeat call-outs caused by poor DHW/CH switching.

Compatibility :

• Ecotec Plus 824: VUW 246/5-5 R2, VUW 246/5-5 R4
• Ecotec Plus 825: VUW 256/5-5 R4
• Ecotec Plus 831: VUW 316/5-5 R2 (NG/LPG), VUW 316/5-5 R4 (NG/LPG)
• Ecotec Plus 832: VUW 326/5-5 R4
• Ecotec Plus 835: VUW 356/5-5 R4
• Ecotec Plus 837: VUW 376/5-5 R2, VUW 376/5-5 R4
• Ecotec Plus 838: VUW 386/5-5 R4
• Ecotec Plus 937: VUI 376/5-5 R2, VUI 376/5-5 R4
• Ecotec Plus 938: VUI 386/5-5 R4
• Ecotec Pro 24: VUW 246/3-3 R2, VUW 246/5-3, VUW 246/5-3 R1, VUW 246/5-3 R2, VUW 246/5-3 R4, VUW 246/5-3 R6
• Ecotec Pro 28: VUW 286/3-3 R2, VUW 286/5-3 (NG/LPG), VUW 286/5-3 R1 (NG/LPG), VUW 286/5-3 R2 (NG/LPG), VUW 286/5-3 R4 (NG/LPG), VUW 286/5-3 R6 (NG/LPG)
• Ecotec Pro 30: VUW 306/5-3 R4

Important fitting advice

We recommend that all parts are fitted by a fully qualified Gas Safe registered engineer. If you need help confirming the right part, contact us our team has 10+ years of boiler spares knowledge and friendly chat support to help you quickly.

Delivery

At Boiler Spares Hub, we dispatch orders within 1 working day (Monday-Friday). Orders placed outside working days will be dispatched on the next working day. For delivery options available for this product, please add it to your basket or check our delivery options page.

Returns

We accept 30-day returns. Returns must be in an unopened, sealed box. If we find the item has been used or installation was attempted, we may refuse the return.

Frequently Asked Questions (FAQ’s)

1. What is Vaillant 0020020015?
A diverter 3-way valve used in selected Vaillant ecoTEC Plus/Pro boilers to switch flow between heating and hot water.

2. What does the diverter valve do?
It directs heated water either to the radiators (central heating) or to the hot water circuit when a tap is opened.

3. What are common signs it needs replacing?
Hot water fluctuating, DHW/CH not switching properly, radiators warming during hot water use, or inconsistent temperature/flow.

4. How do I confirm fitment?
Match the part number 0020020015 and your boiler’s exact model/range (and gas type where applicable).

5. Should this be fitted by an engineer?
Yes water/combustion-adjacent boiler components should be installed and checked by a qualified engineer.