4.3
Parameters
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.
4.3.1
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 NFPA 72 - a transport time of 120 seconds (max). 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.
4.3.2
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 4-2: Flow Delay Settings for the VPR-SD1 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.
Hochiki America Corporation
FireNET Vapor VPR-SD1 Product Guide
www.hochiki.com
29
