Defrosting 01.03.2020 10:01 01.03.2020 11:16

Detection of moisture in the system of protection of gutters and their subsequent defrosting can take advantage of the Foxtrot system with connected sensors ETOR-55 and control of the heating cables placed in the gutters.

When the brass detection plates are dry, they are electrically isolated from each other, but the presence of moisture causes their interconnection. Evaluating the presence of moisture is done by measuring the resistance of the sensor by the respective system inputs.

There is a heating element cast between the detection plates, which slightly heats the sensor, optimizing its function. This feature is required for the humidification of fresh snow, whose electric conductivity is not sufficient.

The ETOR-55 sensor should be put in the gutter in the place, where the moisture usually occurs first, or is present the longest (near the drainpipe, or in heavily exposed areas), to be constantly in contact with water flowing from the melting snow.

Never install the sensor outside the heated area; it must be in a horizontal position.

Place the sensor with the detection pads on the top and glue it with silicone.

It is recommended that two moisture sensors are connected in parallel and located in two different places.

Larger areas can be fitted with multiple sensors, which may be connected in parallel or separately; the second option allows defrosting of individual zones separately.


Heating the ETOR sensor has the power input of approx. 2.5 W at 24 V supply. Heating of the ETOR sensor can be switched by the system relay output, e.g. the output of the C-IS-0504M module, to which the ETOR sensors are also connected (a maximum of 2 sensors per separate module inputs) - see the following wiring diagram.

The value of the outdoor temperature is required for the system to work properly; a separate outdoor temperature sensor can be put in the potentially coldest place of the roof (facing north), on the other hand, while the ETOR sensor should be installed in the hottest spot (facing south).


Fig. 1. A basic wiring of the ETOR sensor, defrosting of gutters.


  1. A standard length of the supply cable is 10 m, but it can be extended with a separate cable 4 x 1 mm2 (e.g. the JYTY) to several dozen meters (a potentially higher resistance of the cable can be compensated by the system software).

  2. Heating of the sensor can be supplied from the Foxtrot system source, or from an independent power supply 24 ÷ 27 VDC.