W1209 12V -50°C to 110°C Digital Thermostat Temperature Control Switch Sensor Module

The W1209 Temperature Controller is a compact, cost-effective, and versatile thermostat module designed for precise temperature-based control of electrical devices. Equipped with a high-accuracy NTC thermistor temperature sensor, the W1209 allows users to automate the operation of cooling or heating systems based on real-time temperature readings.

This module features a built-in relay (rated for up to 125V AC or 14V DC at 20A) that can switch power to connected devices such as fans, heaters, or coolers. The user sets the desired temperature thresholds - both activation (on) and deactivation (off) points - via the onboard interface, which includes a 3-digit digital display and three tactile buttons: Set, Increase, and Decrease.

When the sensed temperature crosses the defined threshold, the W1209 activates or deactivates the relay accordingly, effectively functioning as an automatic power switch. The current temperature is continuously displayed in degrees Celsius, and an onboard LED indicates the relay’s operational status, providing clear, real-time feedback.

This makes the W1209 an ideal solution for a wide range of DIY or embedded applications requiring reliable temperature regulation.

Specifications:

• 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
• Relay Rating: 20A at 14V DC, 16A at 24V DC, 7A at 125V AC
• Measuring Input: NTC (10K 0.5%)
• Waterproof Sensor: 0.3M cable
• Output: 1 Channel Relay Output, Capacity: 20A at 14V DC, 16A at 24V DC, or 7A at 125V AC

Power Consumption:

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

Environmental Requirements:

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

Dimensions:

• 48mm x 40mm x 14mm (LxWxH)

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

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. 

Estas instrucciones de instalación también están disponibles en español (these installation instructions are also available in Spanish): W1209 Instrucciones de instalación y funcionamiento del módulo controlador de temperatura del termostato digital.

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

Want a W1209 with an acrylic plastic case: Click on this link to our W1209 with a case.