Boiler leaking water from bottom of cabinet

Safety first: Turn off power and close the boiler’s isolation valves. Place a container or towels under the unit to catch water.

• Step 1 – Identify leak source: Remove the front cover and use a flashlight to trace the leak upward. Look for wet components, green/white corrosion, or staining.
• Step 2 – Check common points: Inspect the circulation pump, pressure relief valve discharge, automatic air vent, and all unions. Tighten loose fittings gently; do not overtighten.
• Step 3 – Relief valve check: If water is coming from the pressure relief valve outlet, check system pressure. A failed expansion tank or overfilling can cause relief valve discharge.
• Step 4 – Heat exchanger inspection: If water appears to come from the primary heat exchanger body or seams, the exchanger may be cracked or pinholed and will need replacement by a qualified technician.
• Step 5 – Dry and monitor: After tightening or replacing leaking components, dry the area and monitor for further leakage.

Warning: Do not operate the boiler with an active leak. Water can damage electrical components and create shock hazards.