-
No Flow: This mode closes the OAD, and it de-energizes the minimum injection fan.
-
Max Flow: This mode opens the OAD, and it energizes the minimum injection fan.
-
Start: This mode opens the OAD, and the minimum injection fan is off. This mode is used to sequence the damper and the fan to ensure the damper is opening before the fan is energized.
|
Mode |
Min Flow Control Enable |
Damper Ready |
State |
|---|---|---|---|
|
Emergency Flow |
* |
TRUE |
Max Flow |
|
FALSE |
Start |
||
|
No Flow |
* |
* |
No Flow |
|
Max Flow |
TRUE |
TRUE |
Max Flow |
|
FALSE |
Start |
||
|
FALSE |
* |
No Flow |
The Min Flow Control Enable Input indicates that the damper may be opened, and the fan may be energized. This input is True when the Low Limit Process variable is reliable, and it is more than the Low Limit Setpoint.
The Damper Ready input indicates that the damper has started to open, the damper delay has expired, and the fan is now allowed to start.