6
6.
The HD-11 uses a full wave bridge rectifier at its power input, so that it is independent of the polarity of the
input power. It can operate on DC or AC voltages between 12 and 24 volts.
7.
A switching regulator is used to efficiently match the wide input voltage range to the fixed, internal power
system. As a result the power consumption is fairly constant at about 0.75 watts in normal operation, and
1.0 watt in alarm.
8.
The alarm control panel zone inputs must be terminated with end of line resistors (E.O.L.R.), which are
provided with the panel. The HD-11 does not have an internal audible sounder and must be connected to
an audible device that provides at least 85 DB sound output.
POWER UP
When the unit is powered up it performs a self-test during which the green LED light blinks for a period of one and one half to two
minutes. Afterwards, the green LED light will turn on continuously to indicate the unit is in normal operation (ARMED). If the self-test
fails or the green LED light does not turn on continuously do not use. Failure to do so may adversely affect product performance and
result in sickness or death.
When power is first applied to the detector, it will go through a warm-up period of one and one half to two
minutes, during which alarms are inhibited. The green LED light will turn on and off during the delay period. The
green light will turn on continuously (ARMED) afterwards to indicate the unit is in normal operation.
OPERATION
1.
Once the HD-11 is operational (ARMED) the green light will be on continuously. If gas is detected the red
LED (ALARM) turns on and the SPDT alarm relay activates to indicate the alarm condition.
2.
In the configuration, as shipped from the factory, the HD-11 is self-restoring. When the air clears of gas, the
red light turns off and the relay switches to its normal state. A jumper wire on the circuit board can be
clipped to allow the unit to latch in upon alarm. Once latched in, power will need to be interrupted to un-
latch the alarm condition.
The HD-11 can be modified, either before or after installation, to have a latching output. Pull off the
cover and locate the jumper wire labeled “CLIP FOR LATCH IN” on the printed circuit board in the
upper right hand side. Clip or cut this jumper wire and separate the wire ends. Now the unit will stay in
alarm (once gas has exceeded the pre-set threshold) until the power is interrupted. When replacing the
cover, make sure the lights line up with their access holes.
3.
The HD-11 has a supervisory circuit of critical functions. A trouble condition, due to failure of a non-reliable
component, results in both lights switching on and off and the normally closed trouble relay opening. A
power failure also causes the trouble relay to open.
! WARNING
