Rust stains or water inside burner compartment of high-efficiency furnace

Safety first: Turn off power and gas. Combustion components may be hot.

• Inspect collector box outlet: Remove hoses from the collector box and check for obstructions at the outlet.
• Check vent slope: Verify that horizontal vent runs slope back toward the furnace per Rheem specifications so condensate drains correctly.
• Examine collector box: Look for cracks or leaks around seams. A cracked collector box usually requires replacement.
• Service condensate trap: Clean and reinstall the trap as described in the previous entry.

Excessive internal corrosion can shorten furnace life; have a professional evaluate if rust is extensive.