Boiler leaking water from bottom of cabinet or around piping connections

Safety: Turn off power and close the boiler isolation valves. Hot water can cause burns.

• Locate source: Dry the area and observe where water first appears—relief valve discharge pipe, joints, underside of heat exchanger, or air vent.
• Relief valve: If water is coming from the relief valve discharge, check system pressure. If pressure is above spec, the expansion tank may be failed or overfilled. Replace the relief valve if it drips at normal pressure.
• Tighten fittings: Carefully tighten accessible unions and compression fittings. Do not overtighten plastic components.
• Air vent: If the automatic air vent is leaking from the cap, replace the vent and ensure the cap is left slightly open per NTI instructions.
• Heat exchanger: If water seeps from the heat exchanger body, the exchanger is likely cracked and must be replaced by a technician.