Boiler’s pressure relief valve is discharging water frequently or continuously.

Safety first: Hot water from the relief valve can cause burns. Keep clear of the discharge outlet when the boiler is hot.

• Step 1 – Check system pressure: Read the pressure gauge when the system is cold and when hot. If pressure rises above the relief valve rating (often 30 psi), there is an expansion or fill issue.
• Step 2 – Inspect expansion tank: Tap the tank; it should sound hollow on the air side and solid on the water side. If it is full of water or leaking, it has failed.
• Step 3 – Check expansion tank charge (pro): With the system depressurized and isolated, measure the air charge at the Schrader valve with a tire gauge. Recharge to the manufacturer’s specified pressure or replace the tank if it will not hold air.
• Step 4 – Verify fill valve setting: Ensure the automatic fill valve is not over-pressurizing the system. Adjust or replace if it does not regulate to the correct cold pressure.
• Step 5 – Replace relief valve if needed: If pressure is normal but the valve continues to drip, debris may be lodged in the seat. The valve should be replaced; do not attempt to repair it.

Warning: Never plug or cap a relief valve discharge; this is a critical safety device.