Boiler Pressure-Relief Valve Discharging Water
Water dripping from the outside discharge pipe means the PRV is releasing — usually a pressure or vessel issue.
If you see water from the external discharge pipe, your boiler's pressure-relief valve is doing its job — but something is causing over-pressure.
Why the PRV discharges
Over-pressurization (too much top-up), a waterlogged expansion vessel, or a failed valve seat cause the PRV to release water. It's a safety device protecting the system.
The fix
A technician checks system pressure, the expansion vessel pre-charge, and the valve itself, then corrects pressure, recharges or replaces the vessel, or replaces the valve as needed.
Key takeaways
- Don't over-pressurize the boiler
- PRV discharge often points to the expansion vessel
- A failed valve seat may need replacement
- Persistent discharge needs prompt service
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