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 20A at 14V DC, 16A at 24V DC, or 7A at 125V AC. The current temperature is displayed in degrees Centigrade via its 3 digit seven-segment display and the current relay state by an onboard 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 Support Power (DC): 9V minimum to 12V maximum. The maximum current draw is 65mA (operates the module, does not power the load)
    NOTE: The maximum input support voltage should not exceed 12V. In applications such as an automobile or RV where the battery voltage can exceed 12V, a regulator circuit such as a 1N5349A Zener diode and a series resistor in the range of 20 Ohm 1W should be used to limit the voltage to 12V. Alternately, a 12V to 9V buck voltage converter with the input to the converter connected to the battery and the output to the W1209 will provide a stable 9V DC supply for the W1209
  • Measuring Input: NTC (10K 0.5%)
  • Waterproof Sensor: 0.5M cable
  • Output: 1 Channel Relay Output, Capacity: 20A at 14V DC, 16A at 24V DC, or 7A at 125V AC
  • 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/P7: High Temperature Alarm / 0C - 110C / OFF
P8: Factory Reset (Not included in all firmware versions. Can also be reset by pressing and hold the + and - buttons for 5 seconds.)

Package Includes:

W1209 -50°C -110°C 12V Digital Thermostat Temperature Control Switch Sensor Module
NTC 10K Temperature Sensor with 0.3M cable
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.