Model SST-2 Freeze Protection Thermostat

The C-UL-US listed SST–2 Freeze Protection Thermostats replace electromechanical thermostats in cost-sensitive applications requiring ground fault equipment protection (GFEP). The SST–2 is listed by Underwriters Laboratories to Standard UL 873 for Temperature- Indicating and -Regulating Equipment.

Model SST-2 Freeze Protection Thermostat


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 a NEC Class 2 device rated for wet locations.

The SST–2 features a built-in 30 mA GFEP that is digitally filtered to minimize false tripping. A ground fault must be manually reset with the TEST/RESET switch before heater operation can be resumed. The GFEP function is automatically tested along with the heaters whenever power is applied and once every 24 hours thereafter for additional safety.

The SST–2 includes an alarm relay with an isolated SPDT 1 AMP contact. The alarm relay is reverse acting and is normally closed unless there is a ground fault condition, GFEP circuitry fails a test, or when there is a bad temperature sensor.

 The SST–2 Freeze Protection Thermostats operate from automatically selected operating voltages of 120, 208, 240 or 277 volts, single-phase. They control 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′ (610 m) away the SST. They operate in non-hazardous environments in a temperature range extending −40° to 131°F (−40° to 55°C). The rugged non-metallic enclosure is appropriate for installation in indoor or outdoor locations suitable for NEMA 4x applications.

Features & Benefits

  • Automatic freeze protection
  • 40°F (4.4°C) set point
  • Automatic supply voltage selection
  • Two-pole contactor switches up to 30 AMP heater loads
  • Alarm relay with isolated contact
  • Integral 30 mA GFEP
  • C-UL-US listed
  • Simple to install and operate
  • Minimum energy costs



A great thermostat that turns on your system when it is cold enough to freeze and shuts it down when the freeze danger is gone. This unit comes standard with the required GFEPD protection.

Download Datasheet
Download Installation Manual

Click here to get a quote, or fill out our online form for more information.

Back to Top