Vaillant Boiler Ecotec Plus Pressure Relief Valve PRV Replacement

This Vaillant ecotec plus pressure relief valve (PRV) 178985 releases excess system pressure to protect the boiler. However, if the seat wears or debris holds it open, it can drip and the boiler pressure may keep dropping. As a result, you may notice discharge pipe dripping, frequent re-pressurising, and low-pressure lockouts. Therefore, replacing the correct PRV restores safe pressure control and helps prevent nuisance shutdowns.

Compatibility :

• Ecofit Pure System: 612, 615, 618, 625, 630
• Ecofit Pure Combi: 825, 830, 835
• Sustain Combi: 825, 830, 835
• Ecotec Exclusive: 835, 843
• Ecotec Plus System: 612, 615, 618, 624, 630, 637
• Ecotec Plus Combi: 824, 825, 831, 832, 835, 837, 838
• Ecotec Plus Storage Combi: 937, 938
• Ecotec Pro: 22, 24, 28, 30
• Home Combi -A: 25, 30, 35
• Home System -A: 12, 15, 18, 25
• Other: Exclusive 627, Sustain 24, Sustain 34, VWZ MEH 61, VWZ MWT 150

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 does a PRV do on a Vaillant boiler?
It opens to release excess pressure, preventing damage to the boiler and system.

2. How do I know if the PRV is leaking?
Common signs are water dripping from the copper discharge pipe outside and repeated pressure drops.

3. Will a leaking PRV cause low-pressure faults?
Yes. Because water escapes, pressure can fall and trigger low-pressure lockouts.

4. Can I just re-pressurise and keep using it?
You can top up temporarily, but if the PRV is passing, the pressure will likely keep dropping until it’s fixed.

5. Is professional installation recommended?
Yes this is a safety component, so fitting and checks should be done by a qualified heating engineer.