York Parts S1-7990-3591 Gas Furnace Limit SwitchGas Furnace Limit Switch (York Parts S1 7990 3591) is a reliable safety device with a manual reset designed for downflow gas furnaces. It is a compatible replacement for DGAT, DGAM, and DLAS hot surface ignition systems, delivering dependable burner control and overheating protection in residential and light commercial applications. Engineered for seamless compatibility with York replacements, this limit switch matches the electrical ratings of DGAT,

It’s ideal for industrial setups

and 30-second power-open / 10-second spring-return timing ensure fast

It operates as a 1-stage control and offers flexible power options—30V battery or 24V AC hardwire—so you can choose the configuration that fits your installation

This Armstrong unit is built to provide consistent voltage transfer with rugged construction for long-term performance in demanding settings

it connects to your control panels

Easy maintenance with accessible fittings and simple service intervals

high-temperature sensor for dependable flame sensing

Replacement: Replaces C6097B1119

and a blue PVC NEMA 1 enclosure for indoor installations

24 A and 23 W

Operate in demanding environments with robust safety and performance standards

helping maintenance crews monitor tank fills with confidence