IOM SPDB Iss.2 ENG
March 2019
Page 5 of 6
2.2
Electrical & Power Supply
Before installing the unit the flow signal delay timer can be set. Remove the top lid and locate the rotary
position switch mounted on the PCB. Setting ‘0’ will select the minimum delay and setting ‘9’ the maximum
delay. Settings between these will set the delay proportionally. The factory set default position is 9.
Two 20mm holes are provided for cable entry. These should be fitted with appropriate cable glands or conduit
depending upon site requirements. There is no requirement to seal the conduit entry holes if conduit is used.
The SprinklerSense unit requires a D.C. power supply connection. This allows it to be supplied using
proprietary battery backup systems of 24V DC. The average power consumption of the unit is circa 1Watt.
The Amp Hour (Ah) rating of the batteries required can be calculated using an average current draw of 60mA on
a 24V system. This mA figure should be multiplied by the number of hours that the batteries are required to last.
For example, if a 24V backup battery is required to last for 72 hours, 0.06A x 72h = 4.32 Ah.
There-fore a 24V battery supply with a rating of at least 5Ah should be used.
The power supply connections should be connected to the V+ and V- terminals. The Earth terminal should also
be connected to electrical earth.
There are two flow output switches. These both activate at the same time but are electrically isolated from each
other. Each output switch consists of a common connection (COM1 or COM2), a Normally Open contact (NO1
or NO2) and a Normally Closed contact (NC1 or NC2). The contacts are in their Normal state during non-flow
conditions. The output switches should be connected as required, in the same way as traditional flow switch
micro-switch outputs. The contact ratings of 24V D.C. and 500mA should not be exceeded.
D
O NOT CONNECT THE REMAINING TERMINALS WITHOUT REFERRING TO THE SEPARATE LEAFLET WHICH IS
AVAILABLE FOR FURTHER INFORMATION ABOUT THE AUXILIARY CONNECTIONS
.
