Common Installation/Operation Mistakes
Ventilation Components Connected to the Wrong Relays
A common mistake is to control a single fan ventilation system using the “A2 COM” and “A2
NO” relay contacts. If connected this way, the fan will not activate until the target gas
concentration exceeds High Alert level. Unless you intend that the ventilation system activate
only above the High Alert level, operate this type of ventilation system using the “A1 COM” and
“A1 NC” relay contacts. Place jumpers JP5 and JP10 in the “50/100” position so that the fan
will continue to operate if the target gas concentration exceeds the High Alert level.
Ventilation Components Connected to the Wrong Zone
The detector is equipped with two sets of relay contacts – one for each zone. If only one zone
is in use and the ventilation equipment does not activate when expected, verify that the correct
relay contacts are being used for the active zone. If not, you can move the connections to the
other set of relay contacts or use the switch on the control board to swap to the other zone. If
both zones are in use and the wrong ventilation equipment is activating, either swap the zones
using the switch on the control board or swap the wiring connections into the relay contacts.
Configuration Jumper in the Wrong Position
On a single fan ventilation system, the fan is controlled from the “A1 COM” and “A1 NC” relay
contacts. The fan will activate whenever the target gas concentration exceeds the adjustable
Low Alert setting. However, if the jumpers on JP5 and JP10 are positioned in the “2-SPEED”
setting, the fan will turn off if the target gas concentration exceeds the High Alert level.
Therefore, when controlling a single fan system, place the jumpers on JP5 and JP10 in the
“50/100” position.
The “2-SPEED” position on JP5 and JP10 is used for two-speed fan motors or on two-fan
systems in which the low-speed fan is to turn off when the high-speed fan turns on.
Low Alert Level Set at Wrong Concentration
A common tendency is to set the Low Alert concentration at the lowest setting. A Low Alert
setting that is too low can cause frequent cycling of the ventilation system. Set the Low Alert
concentration to that which produces the most efficient ventilation system operation while
protecting people in the monitored area. Setting the Low Alert concentration too high can
create a situation in which the target gas concentration becomes dangerous, or the area
contains too much smoke from engine exhaust. Again, adjust the setting at a level that
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