4-20 mA signal reference
to NEGATIVE (-)
default
to POSITIVE (+)
Earth
terminal
Set of three jumpers JP2
Electrical connector
In its default setting, the sensor uses
the power signal negative as the
4-20mA signal reference; to change
this setting, change the position of the
three jumpers marked JP2.
Output signal
Power supply
4-20 mA
12/24 VDC
+
-
+
-
UR20S Series
gas detectors require regular testing as laid down in the installation manual.
Average service life of sensors: 5 years.
Post-installation checks
UR20S Series gas detectors are factory-set. No on-site setting is required. After
installation, run the following functional test: power up the detector; wait for at least
2 minutes for the sensing element to warm up; check correct operation of the sensor
using a mixture with a concentration of 50% of the LEL of the gas to be detected (CH
4
and LPG), or of 500 ppm for CO; check the operation of the sensor status LED; check
that the output signal is as follows:
Proportional output signal:
10.5-13.5 mA
Threshold-based output:
18.5-21 mA
CO detector:
18.5-21 mA
LED
Posizione LED di stato sensore
UR20S gas detector status
LED status
Warm-up
2 flashes/sec.
Fully operational
1 flash every 10 sec.
Pre-alarm
2 flashes every 5 sec.
1st threshold alarm
3 flashes every 5 sec.
2nd threshold alarm
4 flashes every 5 sec.
Fault
Steadily lit
UR20S Series
Gas detector sensor
UR20S Series
– WATTS brand – in
metal housing (Group II protection mode, category 3G, Ex
nA IIC T6) with operating status indicator LED, for indicating
gas alarms by means of a 4-20mA analogue output or a
trip threshold (pre-alarm, level 1 and 2 alarm, fault) that can
be freely set with DIP switches. Available in three versions,
for detecting natural gas, LPG and carbon monoxide (CO).
Compliant with Directives EMC 2014/30/EU and ATEX
2014/34/EU. II 3G, Ex nA IIC T6.
Specification text
Overall dimensions (mm)
UR20S
100
100
155
55
60
Ø 43
CH 22
26
Watts Industries Italia S.r.l.
Via Brenno, 21 • 20853 Biassono (MB) • Italy
Tel. +39 039 4986.1 • Fax +39 039 4986.222
infowattsitalia@wattswater.com • www.wattsindustries.com
© 2017 Watts
The descriptions and photographs contained in this product specification sheet are supplied by way of information only and are not binding.
Watts Industries reserves the right to carry out any technical and design improvements to its products without prior notice. Warranty: All sales and contracts for sale are expressly
conditioned on the buyer’s assent to Watts terms and conditions found on its website at www.wattsindustries.com. Watts hereby objects to any term, different from or additional to Watts
terms, contained in any buyer communication in any form, unless agreed to in a writing signed by an officer of Watts.
UR20S-TS-IT-W-UK-01-18-Rev.2
