The ETI® SST-2 is an automatic ambient or pipe sensing freeze protection thermostat that is simple to install and operate. It is ideal for pipe freeze protection and snow melting applications in residential environments. The SST–2 operates heaters at temperatures below 40°F (4.4°C) and turns them off above 42°F (5.5°C). The external temperature sensor (supplied) is an NEC Class 2 device rated for wet locations.

The SST-2 also features built-in 30 mA, self-testing Ground-Fault Equipment Protection (GFEP) capability, digitally filtered to minimize false tripping. A ground-fault alarm must be manually reset using the Test/Reset switch before heater operation can continue. The SST–2 includes an alarm relay with an isolated SPDT 1 AMP contact. The alarm relay is reverse acting and is normally energized unless there is a ground fault condition, GFEP circuitry fails a test, or when there is a bad temperature sensor.

The SST-2 operates from automatically selected operating voltages of 120, 208, 240 or 277 volts, single-phase. It controls heater loads of up to 30 amps while consuming less than 2 watts when idling. The temperature sensor is an NEC Class 2 device that can be located up to 2,000 feet (610 m) away from the SST.

Key benefits

  • Ambient or line sensing
  • Fixed set point of 40°F (nonadjustable)
  • 20' probe (extendable up to 2000 ft)
  • Built-in GFEP protection
  • 30 A at 100 - 277 V
Connection and Protection