INSTALLATION INSTRUCTIONS
Hydrosense Conventional Water Detection System
Document Part No. 3500012 REV03
Page | 12 of 27
Detection zone wiring
The detection zones provide a nominal 24V DC to power the Hydrosense devices.
The wiring is monitored for open and short circuit fault conditions by removing the 6K8 end
of line monitoring resistors that are supplied fitted to the control panels’ terminals and
placing it in the last Hydrosense Probe junction box or discarded if Hydrowire Connection
Interface is wired to the zone circuit. Detection zone circuits must be wired as a single, radial
circuit with no spurs or T junctions to enable the monitoring circuit to work correctly.
Control relays
Volt free changeover relay contacts are provided for local control and signalling if required.
These contacts are rated for switching signalling circuits only and the maximum 30VDC
1Amp should not be exceeded under any circumstances.
Typically, the Aux 24V output of the control panel is switched through these relays and used
to control other systems.
Fault relay
The fault relay is normally energised and will de-energise upon any fault condition including
total loss of power.
Local Alarm relay
The local fire relay will energise upon activation of a alarm condition on any of the zones or
pressing of the sound alarm button on the front panel. The relay will remain activated until
the alarm is silenced or the panel is reset. This relay will not operate upon activation of the
remote AL input or when an alarm condition is triggered on a zone that is in test mode. This
makes the Local fire relay suitable for inter panel signalling without the panels latching each
other.
Alarm relay
The alarm relay will energise upon activation of an alarm condition on any of the zones. The
relay will remain activated until the control panel is reset. This relay will also operate upon
activation of the remote AL input and the sound alarm button.
