BoilerTroubleshooting2026-02-26
Water from the Boiler Overflow Pipe
Water from the overflow (discharge) pipe means the relief valve is releasing pressure.
If the external overflow pipe drips, your boiler is shedding excess pressure for safety.
Why it happens
Over-pressurization, a waterlogged expansion vessel, or a failed relief valve cause the discharge pipe to release water.
The fix
A technician corrects system pressure, recharges or replaces the expansion vessel, or replaces the valve.
Key takeaways
- Overflow drip = relief valve releasing
- Often the expansion vessel
- Don't block the pipe
- Needs a technician to fix the cause
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Frequently asked questions
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