Selectable flow balance control during 100% recirculation air
When parameter SAF-01 is not set to “0”, the flow-balance function is enabled. This means that during the 100% recirculation condition (as long as the input "DamperCtrlSig" has a value of “−1”, or when the plant mode equals a code of 1, 2 or 6), the return- and supply air flow will be equalized.
In case the return fan is sized smaller than the supply fan, the supply air flow must be limited to the maximum return air flow.
The setpoint for this flow balance control, which counts to both fans, is defined by parameter SAF-01 in m3/h, while the proportional band and integral time respectively are defined by the parameters SAF-02 and SAF-03.
Description |
Default value |
SAF-01: predefined flow during 100% recirculation; 0 = disable |
50000 m3/h |
SAF-02: P-band flow balance control |
1000 m3/h |
SAF-03: I-time flow balance control |
0 sec |
The next figure shows the internal control signal of the flow balance control, in relation to its setpoint and proportional band.
After start-up, when the fan enable signal becomes true (=1), the integral part of the duct static pressure controller is delayed by a time defined by parameter DSP-03.
After start-up, when the fan enable signal becomes true (=1), the integral part of the duct supply air flow controller is delayed by a time defined by parameter SAF-03.
Description |
Default value |
DSP-03: I-time static pressure control |
0 sec |
SAF-03: I-time flow balance control |
0 sec |