When installing the gas detector, adhere to the following rules:
- fit approximately 20/40cm from the floor for gases heavier than air (LPG);
- fit approximately 20/40cm from the ceiling for gases lighter than air (natural gas);
- fit approximately 150/200cm from the floor for gases with similar density to air (CO). Since CO is a toxic gas, the gas detector
must always be fitted at the breathing height of the room's occupants.
20-40 cm dal soffitto
1,5-2 m dal
pavimento
20-40 cm dal
pavimento
Light gases (e.g. natural gas)
Gases with similar density to air
(e.g. carbon monoxide)
Heavy gases
(LPG, petrol vapour)
The
UR20S Series
gas detector consists of an electronic board, which processes the signal from the sensor and generates
an output signal to send to the gas detector control units on the basis of the concentrations detected. The board is mounted
in a hermetic aluminium housing, which also contains the sensor, fixed at the bottom of it. Change the position of DIP switch 5
to select the detector's operating logic.
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
Proportional output signal (default) Threshold-based output signal
Housing
Electrical
connector
Cable gland
Electronic
board
Operating logic DIP
switch
Sensor
UR20S Series
gas detectors are equipped with an internal sensor that is sensitive to the different gases to be monitored.
After a warm-up and stabilisation period, in which the sensing element comes up to optimum operating temperature, the gas
detectors continuously measure the concentration of gas (CH
4
, LPG, CO depending on model) and generate a proportional
or threshold-based output signal.
Proportional output signal:
the electrical output signal is proportional to the gas concentration, expressed as a percentage
of LEL (Lower Explosion Limit) for flammable gases, and in parts per million for toxic gases.
Threshold-based output signal:
when the concentration of gas in the room reaches certain threshold values, the detector
generates electrical output signals. The gas concentration thresholds are expressed as a percentage of LEL (Lower Explosion
Limit) for flammable gases, and in parts per million for toxic gases.
The signal generated must then be managed by the CIVIC Series (or similar compatible) gas detector control units, which
indicate the alarm state by means of a visual or audible alarm.
Operation
Installation
In addition to general considerations, also take account
of the following when selecting the installation position of
the gas detector: proximity of possible gas escape points;
distance of at least 1.5 m from heat sources and ventilation
apertures; never fit in poorly ventilated areas where gas
pockets may occur; keep away from objects that might
obstruct the natural movement of the gas; do not fit in the
immediate vicinity of machines that routinely emit gas in the
course of operation; the installation environment must have
a temperature of between -20°C and 50°C and relative
humidity of less than 90% non-condensing. The device must
be powered off before fitting or removal. The number of gas
detectors to install in an environment is proportional to its
height and surface area.
Electrical connections
The sensor must be installed in accordance with EN 60079-14. Use cables with the following minimum sections in relation to
their length:
In environments exposed to electromagnetic interference, use shielded cable. The sensor must be earthed using the system
provided.
Cable length
Minimum section of cable
< 100 m
0.75 mm
2
< 200 m
1 mm
2
< 500 m
1.5 mm
2
3
Watts Water Technologies, Inc.
