Type / N.
Rev.
Data
Page
Total pages
EW095.605
5
November 2010
29
96
EsiWelma
s.r.l.
4.4.2
Extended structure
When the devices exceed the power that can be managed by the control unit (30
±
1W)
an external uninterruptible power supply (UPS) is necessary. The example below
represents a system with three boilers, each one fitted with a gas cut-off solenoid valve.
Fig. 4.11 – Extended structure of the system (example)
One methane gas detector (URG40SS) is installed near each boiler and one carbon
monoxide detector (URO40SS) covers the whole premises. A display module is placed at
the entrance to monitor the system status without having to use the control unit.
Each methane gas detector is interfaced with a relay module that powers a local audible
alert in the event of pre-alarm, in alarm threshold one it shuts off the boiler solenoid valve
and in alarm threshold two it shuts off the general gas solenoid valve.
Pr
Bus
Power supply (12 Vdc)
UPS
M
A
R
4
0
URG40..
URG40..
URG40..
URO40..
M
M
M
A
R
4
0
M
A
R
4
0
M
D
D
4
0
M
M
B
o
ile
r
1
B
o
ile
r
2
B
o
ile
r
3
General
Solenoid valve
Solenoid valve
1
Solenoid valve
2
Solenoid valve
3
Pr
Pr
1s
1s
1s
2s
Содержание Sensigas EW40
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