Discovery ASD-1 Product Guide
Apollo Fire Detectors
16
www.apollo-fire.co.uk
5.3
Set-up Notes
The Fan Speed, Flow Limits and Flow Sensitivity need to be set for each installation prior to Flow Calibration
and testing. It is not possible to provide the settings for all possible installations but the following guidelines
should assist in the commissioning of the unit.
5.3.1
Fan Speed
The Fan Speed should be set as high as possible to achieve the fastest transport time from the sampling point
to the detectors, this is especially important for longer pipe lengths and for installations that must conform to
the requirements of EN54-20 (refer to Chapter 8). There is, however, a balance to be achieved between
performance and the power requirements for the system and reference should be made to the current
consumption figures in the specifications prior to setting this value.
5.3.2
Flow Delays
By default, an increase or decrease in flow beyond the FLOW HIGH and FLOW LO limits will result in a
FLOW FAULT after a delay of approximately 30 seconds. Once the flow is returned to a normal level, the fault
condition will be cleared within 18 seconds.
In environments where the sampled airflow may be affected by sudden temperature or pressure changes, or if
there is a risk of physical interference of the sampling point (e.g. prison cell applications) then it may be
necessary to increase the delay between when flow limit has been exceeded and instigating a FLOW FAULT
condition.
Table 5-2: Flow Delay Settings for the Discovery ASD-1 system
Bargraph LED
Flow into Fault Delay (Seconds)
Flow out of Fault Delay (Seconds)
0
15
2
1
30
18
2
60
18
3
90
18
4
120
18
5
150
18
6
180
18
7
210
18
8
240
18
9
270
18
Note:
Timings are approximate.
Note:
The default flow delay setting is 1.
5.3.3
Flow Sensitivity
This setting determines the units responsiveness in reporting blocked sampling points or broken pipes.
The default flow sensitivity value of 9 will configure the unit to declare a flow fault whenever there has been a
change in volumetric airflow of ± 20% from the calibrated reading for at least the duration of the flow delay, see
Section 5.3. For most installations, especially if compliance with EN54-20 is required, the default setting
should be used.
In certain circumstances, such as rapid changes in ambient air pressures due to air handling units, doors
opening/closing etc. the default setting may appear to be too sensitive. Under these conditions, the flow delay
setting should be increased to allow time for the air pressures to stabilize after the temporary event.
Only under extreme environmental conditions or non standard pipe configurations should decreasing the flow
sensitivity be considered.
