Digital Differential Outlet Thermostat for Attic Ventilation


  • Model: TD320


Product Description:

TD320 is the newer model that replaces the previous model TD300.

What is new:
·         Output sockets are changed to standard NEMA 5-15 receptacles.
·         Sensor connectors are changed to bigger 3-pin connectors for easier handling.
·         A new parameter, Relay Output Mode, is added to allow users re-assigning the heating or cooling output to one or both sockets per the user’s specific application.  
TD320 is a temperature controller for heating, ventilating, and air-conditioning (HVAC) controls using the external medium such as air or water. The controller comes with two sensors. The primary sensor (Sensor1) should be placed in the room or close to the object where the temperature needs to be regulated. The auxiliary sensor (Sensor2) should be placed to monitor the temperature of the external medium. The temperature difference between two sensors can be used as an additional criterion for controlling the power output.
Two independent channels are available, and each channel has its own set temperature. There are two output sockets, one for cooling and one or heating. The controller also offers the flexibility of re-assign the heating or cooling output to one or both sockets per the user’s setting.
This is a plug-n-play controller. No additional wiring is needed. Both the heating and cooling controls are on/off control. It is similar to a mechanical thermostat but has much higher precision due to adjustable hysteresis band, high precision sensor, and digital read out. Anti-Short (AS) function is available for the cooling channel to protect the compressor from being turned on/off frequently.
Two digital silicon band gap sensors are used. This type of sensor is much more reliable in moist environment comparing to thermistor sensors. It can be immersed in water over an extended period of time. It also has high uniform accuracy over an entire specified temperature range. Two sensors are interchangeable. One of the sensor has a 12-feet (2 m) cable, which makes it easy to reach the external medium. For customized sensor cable length, please contact customer service.  

Temperature Control Range
 -50 ~ 105°C, -58 ~ 221°F
Temperature Resolution
0.1°C (between -9.9 ~ 99°C)
1°C (between -50 ~ 10°C, 100 ~ 120°C)
0.1°F (between -9.9 ~ 99.9°F )
1°F (between -58 ~ 10°F, 100 ~ 248°F)
Temperature Accuracy
0.5°C or 0.9°F
Temperature Control Mode
On/Off Control. Heating  and Cooling
Temperature Control Output
10A, 120V or 240V AC *
Audio Alarm
High and Low Limit
Sensor Type
Silicon Band Gap Sensor
Sensor Size
0.25'’ O.D. (6.35 mm) , 1'’ Length (25 mm)
Operating Temperature
-20 ~ 50°C (0°F ~ 120°F)
3.6'’ x 5.5'’ x 1.8'’ (91 x 140 x 46 mm)
Input Power 
85 ~242VAC, 50Hz/60Hz
Sensor1 Cable Length
6 ft (2 m)
Sensor2 Cable Length 12 ft (4 m)
Power Cable Length
3ft (1m)
 One (1) Year

  • The controller can display temperature unit in Celsius or Fahrenheit.
  • Unlike the PID controllers we sell, this on/off controller will not hold the temperature as tight if the system had very slow and delayed response. Some temperature overshoot is normal.
  • Either the heating or the cooling device is limited to 10 Amps. The output voltage is the same as the input voltage.  When the controller is plugged into 120V AC, the output will be 120VAC. If the controller is connected to 240 VAC, the output will be 240VAC also.
  • The input power plug is a US NEMA 5-15P plug. The output sock will accept US, Australia, or European continental plug (CEE7/7). Optional input & output travel plug adapters are offered. Please check here for more details.
Click here for the instruction manual.

Click here for its replacement sensor.

This product was added to our catalog on Tuesday 18 March, 2014.

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