Hard Start Kit, 300% Torque Increase, 90/277V

Product Overview

The SUPCO SPP5 Hard Start Kit is a two-wire PTC relay and start capacitor assembly designed to increase compressor starting torque in single-phase HVAC and refrigeration systems. Part of the SUPCO Super Boost Series, this compact hard start kit is rated for operation from 90 to 277 VAC and provides up to 270 oz-in of starting torque enhancement. The SPP5 improves compressor starting performance in low-voltage, high head pressure, or long line set applications, ensuring reliable system start-up under demanding conditions.

Technical Specifications

• Manufacturer: Sealed Unit Parts Company (SUPCO)
• Model Number: SPP5
• Series: SPP Super Boost
• Description: 2-Wire Hard Start Kit with PTC Relay and Start Capacitor
• Reference Number: 1645
• Voltage Range: 90 to 277 VAC
• Starting Torque Output: 270 oz-in (maximum)
• Connection Type: Two-wire connection; installs in parallel across compressor run capacitor
• Components:
  • PTC (Positive Temperature Coefficient) solid-state start relay
  • Start capacitor – non-polarized, oil-filled construction
• Function: Provides temporary start boost to single-phase compressor motors for improved starting under heavy load conditions
• Motor Compatibility: Hermetic compressors used in 120V and 230V systems
• Typical Application:
  • Air conditioning and refrigeration compressors
  • Heat pumps and condensing units
  • Systems experiencing hard starting due to voltage drop or high system pressure
• Operating Principle:
  • PTC relay energizes start capacitor during motor start sequence
  • Relay deactivates the start circuit automatically as motor reaches operating speed
• Mounting: Compact in-line design for direct mounting within equipment electrical compartment
• Performance Characteristics:
  • Improves compressor start-up efficiency and reliability
  • Reduces start-up current draw and mechanical stress
  • Enhances performance under low voltage or high temperature operation
• Electrical Termination: Factory-sealed wire leads suitable for crimp or spade terminal connections
• Housing Material: Thermoplastic encapsulated enclosure
• Temperature Rating: Standard ambient HVAC/R electrical compartment range
• Compliance:
  • UL and CSA recognized components
  • Meets applicable HVAC/R electrical accessory standards
  • Manufactured under ISO 9001 quality assurance program
• Installation: Connect across the run capacitor terminals in accordance with manufacturer wiring diagram
• Service Environment: Suitable for indoor or protected outdoor use in HVAC/R enclosures
• Country of Manufacture: United States

Summary

The SUPCO SPP5 Hard Start Kit is a 2-wire, 90–277 VAC PTC relay and start capacitor assembly delivering 270 oz-in of torque assistance. Designed for hermetic single-phase compressors, it enhances start reliability and performance in HVAC and refrigeration systems under low-voltage or high-load conditions.