Boiler displays E13 and will not start; condensate present around unit

Safety: Turn off power before working on the condensate system. Condensate is mildly acidic; wear gloves and eye protection.

• Inspect trap and tubing: Locate the Dettson condensate trap and drain line. Check for kinks, sags filled with water, or visible blockages. Remove and flush the trap with clean water if accessible.
• Check for freezing: In cold climates, ensure the condensate line is not run through unheated spaces without insulation. Thaw gently if frozen and correct routing.
• Verify slope: The drain line should slope continuously downward to the drain. Adjust supports to eliminate upward loops.
• Condensate switch: Some Dettson boilers use a float or level switch. Inspect and clean the switch housing. If the switch is stuck or defective, it must be replaced.
• Reset and test: After clearing the drain, reset the boiler and observe for normal operation and no leaks.