The PM-072 Slab Sensor is designed to measure temperature in outdoor slabs and pavers. Its high density polyethylene (HDPE) sleeve makes it perfect for use in conduits, soils, or concrete, and it is suitable for direct burial. Sensor includes 20 feet of 2 conductor cable and is a 10k thermistor.
We suggest use in conjunction with the PM-L2 Kit's aerial sensor, you can achieve slab temperature control to lower your operating cost.
Controlling the slab temperature is critical to minimizing the cost of snow melting. This requires that either a Snow / Ice Sensor PM-090 or a Slab Sensor PM-072 is installed. The PM-090 Snow / Ice Sensor contains a built-in slab temperature sensor. While the control will continue to operate without a slab sensor installed, operating costs will be much higher. The slab is operated using "slab outdoor reset". As the outdoor temperature gets colder, the heat loss of the slab increases. In order to keep the slab surface at a constant temperature while operating, the inner core of the slab must be heated above the melt temperature setting. The amount that the slab inner core temperature is above the melt setting is proportional to the outdoor temperature. Since the slab sensor is installed below the surface of the slab, it is not measuring the true slab surface temperature but rather the inner core temperature. The control automatically compensates for this temperature difference. However, the Slab item in the View menu displays the actual measured temperature, so it is normal to view slab temperatures that exceed the melt temperature setting.
Though the PM-072 is designed for direct embedding in slab material, it is recommended to install them in a metal or plastic sleeve. This allows for easy replacement if the sensor should ever fail or have to be relocated. The sensor should be placed 1 inch (25mm) below the slab surface and 1/2 way between the electric cables (or hydronic tubing).
Sensor wiring can be extended up to 500’ (150 m) using 18 AWG wire. Wire splices should be properly soldered and protected in an accessible, waterproof junction box.