This TD500 controller is for precision temperature control in the beer fermentation process. It contains two temperature probes. One probe is placed in the beer to accurately measure the beer temperatuer, the other probe is placed in the chiller, outside of the tank. This probe is to set the boundary for heating and cooling so that the chiller does not become too cold or too hot during operation. 

This dual-probe controller provides higher precision control than the single-probe controller. The single-probe controller has some limitations: If the probe is placed inside of the liquid, the outer layer of liquid might get too cold during cooling, because the liquid cools much slower than the air surrounding it. During heating, the outer layer of liquid might also get too hot.  If the probe is placed in the chiller (outside of the tank), you may not know the true temperature of the beer inside, because the fermentation is an exothermic process.  For dual-probe controller, when you set the temperature of fermentation at 58 degree, you can set the boundary (chiller temperature for probe 2) at 48 degree. The temperature in the chiller will never get lower than 48 degree during the cooling process.

The controller has two outputs. One for heating and other for cooling. By using both cooling and heating devices, the refrigerator can be controlled at specific temperature regardless in hot summer or cold winter.

 

1) Free hanging probe with 6 ft cable for thermowells. This probe is the same as Sensor 2. (Thermal grease SI-07 sold seperately.)

2) 4" long, 1/4" NPT liquid tight sensor. Cable length is 8 ft. 

3) 4" long, 1/2" NPT liquid tight sensor. Cable length is 8 ft. 

4) 4" long, tri-clamp sensor, which works with 1", 1 1/2", 25 mm, 33.7mm and 38 mm tri-clamp systems. (In other words, these 1", 1 1/2", 25 mm, 33.7mm and 38 mm systems have the same flange dimension.). Cable length is 8 ft.