If these external factors are ruled out

Environmental Protection: The totally enclosed fan cooled housing protects internal components from debris

while the second switch serves as a high-limit safety to shut down the burner or compressor at 3/8-inch below the waterline

The 35-70 series control utilizes sophisticated flame sensing circuitry to monitor combustion and provides a single-try ignition sequence

Most failures result from excessive dust buildup causing imbalance

Reznor 136965 Venter 318172-701 If these external factors areThe Reznor 136965 is a high performance CA1 venter assembly designed specifically for large scale Reznor unit heaters, providing critical motor driven exhaust for systems between 350,000 and 400,000 BTUh. This 115V single phase power assembly operates as a motorized exhauster, ensuring safe dilution of flue gases in environments with negative pressure or where horizontal venting is required. The integrated 24V relay acts as a safety barrier, isolating