W1209 -50°C to 110°C Digital Thermostat Temperature Control Module with Plastic Case

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  • Regular price $5.29

This W1209 is a low cost yet highly functional thermostat controller with a clear acrylic plastic enclosure. This module intelligently controls power to most types of electrical devices based on the temperature sensed by the included high accuracy NTC remote temperature sensor.

The cooler, heater or fan is connected to a power supply through the relay contacts K0 and K1, and the temperature on/off setpoints are programmed into the W1209 using the onboard Set, Increase and Decrease buttons and display. The relay contacts are then open and closed, acting as a power switch for the cooler/heater, based on the temperature measured by the NTC temperature sensor (included with the module) and the setpoints programmed into the W1209 controller.

Although this module has an embedded microcontroller, no programming knowledge is required. 3 tactile switches allow for configuring various parameters including on & off trigger temperatures. The on-board relay can switch up to a maximum of 125V AC or 14V DC at 20A. The current temperature is displayed in degrees Centigrade via its 3 digit seven segment display and the current relay state by an on board LED.


  • Temperature Control Range: -50 ~ 110 C
  • Resolution at -9.9 to 99.9: 0.1 C
  • Resolution at all other temperatures: 1 C
  • Measurement Accuracy: 0.1 C
  • Control Accuracy: 0.1 C
  • Refresh Rate: 0.5 Seconds
  • Input Power (DC): 12V
  • Measuring Input: NTC (10K 0.5%)
  • Waterproof Sensor: 0.5M cable
  • Output: 1 Channel Relay Output, Capacity: 20A
  • Includes a Clear Acrylic Case (Box) with mounting screws (assembly required)

Power Consumption:

  • Static Current: <=35mA
  • Current: <=65mA

Environmental Requirements:

  • Temperature: -10 ~ 60 C
  • Humidity: 20-85%


  • W1209 Board (LxWxH): 48mm x 40mm x 14mm (1.9" x 1.6" x 0.6")
  • Case (Assembled L x W x H): 59mm x 51mm x 18mm (2.3" x 2.0" x 0.71")

Settings Chart:

Long press the “SET” button to activate the menu.

Code: Description / Range / Default Value

P0: Heat or Cool / C/H / C
P1: Hysterysis Set / 0.1C - 15C / 2C
P2: Upper Limit / 110C / 110C
P3: Lower Limit / -50C / -50C
P4: Temperature Calibration / -7.0C ~ 7.0C / 0C
P5: Delay Start Time / 0-10 mins / 0 mins
P6: High Temperature Alarm / 0C - 110C / OFF

Package Includes:

W1209 -50°C -110°C 12V Digital Thermostat Temperature Control Switch Sensor Module
NTC 10K Temperature Sensor with 0.5M cable
Acrylic Clear Case Box with mounting screws (assembly required)
Online documentation & usage guide

Need a longer probe? See our 1 Meter long NTC Thermistor Probe that can be used with the W1209.

Want a W1209 without the case: Click on this link to our W1209 without a case

For detailed installation, operation, and programming instructions, see the W1209 Digital Thermostat Temperature Controller Module Installation and Operating Instructions on the Envistia Mall support website.