Modine 3H0400780002 Limit Switch

The Modine 3H0400780002 Limit Switch is a critical OEM high limit safety control designed for precise thermal monitoring in Modine unit heaters. This stalk mount limit switch is engineered with a factory-calibrated L200F-40F temperature profile, meaning the SPST (Single Pole Single Throw) circuit is normally closed and triggers to open on rise at 200°F. Once the plenum temperature drops by the 40°F differential to 160°F, the switch provides an automatic reset to resume standard heating cycles. This component serves as the direct replacement for legacy part numbers 5H75769-2 and 5H0757690002, ensuring seamless mechanical and electrical integration without field modifications.

Built for the rigors of commercial and industrial HVACR environments, the 3H0400780002 is compatible with a wide range of Modine Hot Dawg and industrial series, including HD60, HD75, HD100, HDS, HDB, and HDC models. Its rugged stalk mount design facilitates accurate sensing of high-temperature conditions directly within the airflow or heat exchanger cabinet, preventing heat exchanger fatigue and potential fire hazards. For technicians, using this genuine Modine replacement part ensures the high-limit safety string remains compliant with the original equipment manufacturer's specifications for over-temperature protection.

• Direct OEM Replacement: Replaces 5H75769-2 and 5H0757690002 for 100% compatibility with Hot Dawg unit heaters.
• Safety Calibration: 200°F fixed trip point protects the heat exchanger and internal components from thermal stress.
• Automatic Reset: Resets at 160°F, reducing unnecessary service calls for manual intervention after minor temperature spikes.
• Stalk Mount Design: Provides stable positioning and precise thermal sensitivity within the heater plenum.
• Broad Application: Fits BTS, PTS, and HD series models, making it a versatile stock item for service vans.

What happens if the 3H0400780002 limit switch fails?
A failed switch usually results in a "no heat" call because the safety circuit remains open, preventing the ignition control from initiating the burner sequence. Conversely, if it fails to open, the unit may overheat, risking damage to the combustion chamber.

Does this part require a conversion kit for different gas types?
No, this is a thermal safety switch and operates independently of the fuel source (Natural Gas or Propane). It monitors the air or cabinet temperature regardless of the burner configuration.

Can I use a surface mount switch to replace this stalk mount model?
It is not recommended. The 3H0400780002 is a stalk mount switch specifically designed to reach into the airflow for accurate sensing. A surface mount alternative may not react quickly enough to over-temperature conditions, compromising safety.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.