Condensing boiler shuts down with 'Condensate Block', 'Drain Fault', or similar; water may be visible in the base.

Safety first: Turn off power. Condensate is mildly acidic; wear gloves and eye protection.

• 1. Locate condensate trap: On Weil-McLain condensing models (Ultra, ECO, Evergreen), find the clear or opaque plastic trap assembly near the bottom of the boiler.
• 2. Inspect for blockage: Disconnect the outlet tubing and check for slime, debris, or scale. Flush the trap with clean water until it runs clear.
• 3. Check drain line: Ensure the condensate tubing slopes continuously to a drain and is not kinked or frozen. Thaw gently if frozen and improve insulation or routing.
• 4. Prime trap: Refill the trap with clean water before reconnecting to ensure proper sealing.
• 5. Reset boiler: Restore power and reset the control. Verify that condensate flows freely during operation.