Furnace displays E16; condensate pump runs frequently or furnace shuts down during wet weather.

Safety: Turn off power before working on the condensate system. Water and electricity are a dangerous combination.

• Inspect drain tubing: Locate the condensate drain line from the furnace's collector box or drain pan. Check for kinks, sags, or algae buildup. Remove and flush with warm water if clogged.
• Clean condensate trap: If your Alpha furnace has a removable trap, detach it and rinse thoroughly to remove debris and slime. Reassemble according to the manual, ensuring correct orientation.
• Check condensate pump (if present): Pour water into the pump reservoir and verify it activates and pumps water away. If it does not run or fails to pump, replace the pump.
• Reset float switch: Some systems have a float switch in the drain line. Once water is cleared, the switch should close automatically.

After clearing, restore power and test a full heat cycle. If E16 persists, have a technician inspect the internal condensate passages.