In refrigeration systems, thermal protection at the condenser is essential for preventing system shutdowns, component failure, or fire hazards. A snap disc thermostat mounted to the refrigeration condenser functions as a mechanical switch that cuts power when refrigerant line temperatures exceed a fixed limit. Senasys’ 430 Series, including the 430-301AA25-543, provides a compact, reliable solution for this exact role, using pipe-mount thermal sensing to control system behavior without electronic controllers.
For additional information on our 430 Series, visit the product page.
430-301AA25-543: Pipe-Mount Thermostat for Refrigeration Applications
The 430-301AA25-543 is a ½” pipe-mounted, SPST thermostat that opens at 200°F and resets automatically as the line cools. Designed for direct mounting onto condenser coils, it uses a bimetal disc to detect thermal rise and mechanically actuate circuit changes. This unit is UL and cUL recognized, with switching action suitable for OEM refrigeration platforms where fast thermal response and fixed calibration are required.
As part of the broader 430 Series, this model serves as a go-to configuration for many commercial cooling systems.
How Snap Disc Thermostats Function in Refrigeration Condensers
In a typical refrigeration unit, the condenser coil rejects heat absorbed at the evaporator. If airflow is restricted or the condenser coil becomes obstructed, refrigerant temperatures can rise to unsafe levels. A snap disc thermostat mounted on the refrigeration condenser senses this increase and breaks the circuit to halt compressor function. When the temperature drops below the reset point, the thermostat recloses the contacts and restores operation.
This automatic thermal control cycle occurs without software, sensors, or manual reset—ideal for standalone refrigeration equipment or field-deployable systems.
430 Series Features and Customization Options
The 430 Series offers broad versatility across HVAC and refrigeration applications. Key attributes include:
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SPST snap action for fast, positive switching
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Open or close on temperature rise, depending on application needs
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Custom temperature calibrations from 0°F to 350°F (-18°C to 176°C)
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Factory-preset tolerances with 100% mechanical and thermal inspection
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Available exposed or enclosed discs for environment-specific operation
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Meets UL Standards 873 and 353
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Wiping contacts to extend mechanical life in cyclic applications
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Multiple mounting configurations to suit OEM assembly requirements
The 430 Series uses a ½″ bi-metal disc that reacts instantly to line temperature changes, providing snap action for both limit and control switching. Its construction electrically isolates the sensing element from the current path, avoiding EMI issues and false triggering.
Integration Benefits in Refrigeration Units
OEM engineers and system integrators use the 430 Series to meet thermal protection needs without digital complexity. Benefits include:
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Direct pipe-mount contact for accurate thermal response
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No external sensors or firmware required
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Compact size for installation in constrained spaces
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Customizable set points to match refrigerant system behavior
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U.S. manufacturing for consistent lead time and production quality
In refrigeration units—especially those with outdoor condensers—snap disc thermostats offer protection against airflow blockages, debris buildup, or fan failure. Their ability to cycle autonomously based on thermal thresholds reduces maintenance requirements and improves operational safety.
