5.18 Start-up / shut-down sequence
For safe and optimum operation of the ventilation unit, special switch-on and
switch-off sequences are used to switch the ventilation off and on again.
The ventilation unit is normally not "switched off", but can be switched off for
maintenance work or in emergency situations.
The start-up sequence is used every time except in emergency situations. The
start-up sequence applies also for fire damper test function which is performed
automatically.
Start-up sequences:
1. Startup is initiated.
2.
Only after power return
: Delay time step 2 (to secure start-up time for valves,
fire dampers and ERC).
3.
Only with water heating coil
: Heating coil pump switches on and valve drives to
fully open position.
4.
Only with water heating coil
: TFrPrtHcl temperature level is checked.
If TFrPrtHcl > "Setpoint frost protection if plant on", the start-up may continue.
If not, start-up will wait until setpoint is reached or until set timeout step 4 has
finished.
If TFrPrtHcl is not reached until timeout, an A-alarm is activated, the startup
process is stopped.
5. Open the outside air dampers.
Delay time step 5 (to secure dampers fully open).
If damper output cannot be switched, an A-Alarm is activated, the startup
process is stopped.
6. ERC ramps up to maximum speed.
Heat exchanger bypass closes.
Exhaust fan starts and ramps up to Comfort mode speed.
If fan speed is configured as A‑Alarm, and the feedback signal is not received
within the delay time, an A-Alarm is activated, the starting process is stopped.
Delay time step 6 (to secure “heating up” of heat exchanger)
7. Supply fan starts and ramps up to “unoccupied” mode speed
Delay time step7.
If fan speed is configured as A‑Alarm, and the feedback signal is not received
within the delay time, an A-Alarm is activated, the starting process is stopped.
8. Both fans ramp to required operating mode speed.
Delay time step 8 preparing for normal operation.
9. Normal operating mode is started.
Shut-down sequences:
Executed after normal operation or if startup is interrupted after step 6 is finished.
Shutdown sequence is not used in emergency situations.
1. Shutdown is initiated.
2.
Only with electric heater
: Electrical heaters are switched off.
Delay time step 2.
3. Both fans ramp down to stop.
4. Close the outside air dampers, same time as in start-up step 5.
5. ERC ramps down to stop.
6. Plant is "Off".
Only with water heating coil
: Heating coil is controlled to "Setpoint frost
protection if plant off".
Application functionalities
Start-up / shut-down sequence
5
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