Furnace indicates condensate fault, shuts down during operation, may show water under unit

Safety first: Turn off power before working near water and electrical components.

• Locate condensate trap: Find the plastic condensate trap at the bottom of the heat exchanger. Place a container underneath.
• Clean trap: Remove the trap according to the manual. Flush it with clean water to remove sludge and debris. Check for obstructions in the outlet.
• Inspect drain line: Follow the condensate pipe to its termination. Ensure it is not frozen, kinked, or blocked. Thaw gently if frozen and improve insulation or routing.
• Reassemble and test: Refit the trap, ensuring seals are correctly seated. Restore power and run the furnace, checking for proper drainage and no leaks.

Warning: Condensate is mildly acidic; wear gloves and eye protection when handling and disposing of it.