the start relay is likely defective

When should the pilot orifice be replaced

For HVAC technicians and contractors

or thread the unit into exact alignment within the combustion chamber

replacement is required during every service

System Sensor ST-3 Tube the start relay is likelyThe System Sensor ST 3 is a professional grade metal duct sampling tube engineered for precise air monitoring in commercial and industrial HVAC systems. Designed for duct widths from 2 ft to 4 ft, this 3 foot rigid tube facilitates the intake of air into the detection chamber to ensure rapid smoke identification. This duct smoke detector accessory is specifically built for integration with legacy duct smoke detector models, including the DH100, DH200,