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NTC resistor, yellow and brown wires
°C
-15
-10
-5
0
+5
+10
+15
+20
+25
+30
kΩ
11,4
8,9
7
5,6
4,5
3,6
2,9
2,4
2
1,6
Humidity sensor, white and grey wires: ∞ Ω with dry sensor surface
6.4 Snow and ice sensor with a heating resistor for rainwater gutters ECOA903 (figure 6)
The sensor is equipped with a heating element which melts ice and snow gathered on the sensor. Addition-
ally, the sensor has an NTC resistor to measure the sensor surface temperature as well as two metal pipes as
humidity sensors.
Operating voltage
8 V
Power consumption
3 W
Surface temperature
approx. +4 °C (+39.2 °F)
Connection lead
5 x 0,25 mm; 4 m PVC
Ambient temperature
-30…+80 °C (-22…+176 °F)
NTC resistor, yellow and brown wires
°C
-16
-10
-5
0
+5
+10
+15
+20
+25
+30
+40
kΩ
87,2
61,3
48,8
35
25,5
20,8
15,4
12,7
9,5
8
5,1
Heating element, brown and green wires: 20 Ω
Humidity sensor, white and grey wires: ∞ Ω with dry sensor surface
6.5 Air temperature sensor ECOA904 (figure 7)
The temperature sensor is composed of a cable with an insulated NTC resistor
Connection lead
2 x 0,5 mm; 4 m PVC
Ambient temperature
-30…+80 °C (-22…+176 °F)
NTC resistor, brown and blue wires
°C
-15
-10
-5
0
+5
+10
+15
+20
+25
+30
kΩ
11,4
8,9
7
5,6
4,5
3,6
2,9
2,4
2
1,6
7. Maintenance
Ensure that the surfaces of the sensors installed in ground and gutter are kept clean at all times. Dirt on a sen-
sor surface will prevent its proper function.
A regular inspection of the control unit is recommended so that any alarm messages can be recognized and
repaired within a reasonable amount of time.
By following the maintenance instructions the frost protection system will function properly.
8. Warranty
The warranty period for Ensto ECO900 is 2 years from the date of purchase but no longer than 3 years from the
date of manufacture. Warranty conditions, see
www.ensto.com
.
9. Disposal
Do not dispose of electrical and electronic devices including their accessories with the household
waste.
The product’s cardboard packing is suitable for recycling.
When a heating system is at the end of the life cycle the cables, conduits and electronic components must be
disposed of properly according to local recycling guidelines.