Block Exhaust air
Block Exhaust air| This
block controls a single extract fan of the kind used in a toilet,
bathroom or storeroom. It combines the usual triggers - light, motion,
push button and humidity - with run-on times, a minimum run time, a
minimum idle time and a night set-back. What sets it apart from a hand-built solution is the detection of the rise in humidity: in winter the absolute humidity threshold is often never reached, because the cold supply air keeps the room air dry anyway. The rapid rise while showering, however, is always measurable. Occupancy is taken from the Block Presence block, as with every block element. In the control element you can define per state whether the fan may start at all. See also Presence in general. The matching control element is Block Ventilation; it operates both the ventilation system and the extract fan. For a mechanical ventilation system with heat recovery, use the block Block Ventilation. |
The fan
runs as soon as at least one demand is present:
Minimum run time and minimum idle time override everything else. Without them the fan cycles at the humidity threshold - it starts, lowers the humidity by a tenth of a percent, switches off, and starts over. The minimum run time prevents switching off, the minimum idle time prevents restarting immediately. The maximum run time ends operation when a stuck demand would otherwise keep the fan running indefinitely - a light switch that was forgotten, for example. The fan only starts again once the demand has disappeared in the meantime. |
| The
block records the humidity value once a minute. If the current value is
higher than the value from ten minutes ago by the configured amount,
the rise counts as detected and the fan starts - even if the absolute
threshold is still far away. The detected rise expires as soon as the humidity has fallen below the value at the moment of detection minus the hysteresis. It deliberately does not end at the absolute threshold - that is exactly what is never reached while showering in winter. After a restart of the controller the series of measurements starts empty. Until enough values have been collected, no rise is reported; a false trigger during start-up is therefore ruled out. The absolute humidity threshold works completely normally during this time. The value 0 switches rise detection off. |
| If cycle
operation is switched on and humidity is the only demand, the fan
alternately runs for the set time and stays off for the set time - for
example 30 minutes on, 30 minutes off - until the humidity has
dropped again. It starts with the running time. During the pause the
run-on time after humidity does not apply either. Light, motion and the push button, on the other hand, apply continuously: whoever switches on the light or presses the button gets the fan even during the pause. Afterwards the cycle starts again as long as the humidity stays high. With cycle operation switched off, the fan runs continuously until the humidity has dropped. Setting in the control element: humidity threshold, hysteresis, humidity rise, run-on time, duration after manual switch-on and cycle operation can be changed in the control element under the fan symbol (Operation). Until it was saved there for the first time, the parameters of this block apply. Afterwards the values from the control element apply and changes to the parameters no longer affect them. |
| Within
the configured time window the fan can either be locked completely or
respond to humidity only. The second option is the usual case: at night
the fan should not start every time the light is switched on, but it
should still start when somebody takes a shower. If the time window starts later than it ends, it spans midnight. |
Inputs |
||
| LI |
Light on |
1 = the light in the room is on. After the switch-on delay
this becomes a demand. |
| BE |
Motion |
1 = motion detected. Takes effect without delay. |
| RF |
Humidity |
Relative humidity in the room in %. Basis for the humidity
threshold and for rise detection. If the input is not linked, both are
omitted. |
| TA |
Push button |
The push button toggles: if the fan is running, the
rising edge switches it off, otherwise on. An extract fan has to be
switchable off by hand as well. The manual switch-off applies until no demand is present any more - with the light still on the fan therefore does not start again immediately. Switching on and off by hand takes effect immediately, without the minimum run time and without the minimum idle time. The control element also operates through this address. |
| FR |
Release |
0 = the fan stays off. An input that is not linked counts
as released. |
Outputs |
||
| LU |
Fan |
1 = the fan is running. |
| NL |
Run-on active |
1 = the fan is only still running because of the run-on
time, the actual demand has already disappeared. |
| BT |
Operating hours |
Operating hours since the last acknowledgement. The
counter value is stored on the controller and survives a restart. The
maintenance interval is set in the control element. |
| ST |
Info status |
Status value for the visualisation. The bits are added
up: 1 = light on 2 = motion 4 = push button 8 = humidity threshold exceeded 16 = rise in humidity detected 32 = run-on active 64 = maximum run time reached 128 = minimum idle time running 256 = night set-back active 512 = maintenance due 1024 = fan runs because of manual switch-on 2048 = cycle operation active (running time or pause) |
Parameters |
||
| Switch-on delay light |
The light has to be on this long before the fan starts.
The value 0 lets it start immediately. |
|
| Run-on time |
The fan keeps running this long after light, motion or
push button have disappeared. After switching on with the push button it
also runs this long if no duration after manual switch-on is set. |
|
| Duration after manual switch-on |
The fan runs this long after it was switched on with the
push button. Then it switches itself off again. The value 0 means the
run-on time applies. Pressing the button again switches off earlier. |
|
| Evaluate humidity |
Switches the humidity threshold and rise detection on or
off. |
|
| Humidity threshold |
From this relative humidity onwards the fan starts. |
|
| Humidity hysteresis |
The humidity has to fall below the threshold by this
amount before the demand ends. |
|
| Rise in humidity |
If the humidity rises by this amount within ten minutes,
the fan starts. The value 0 switches rise detection off. |
|
| Run-on time after humidity |
Separate, usually longer run-on time for the humidity
demand. |
|
| Cycle operation at humidity |
Not equal to 0 switches cycle operation on, 0 off (default:
off, i.e. the previous behaviour). If humidity is the only demand, the
fan alternately runs for the on time and stays off for the off time.
Light, motion and push button apply continuously. |
|
| Cycle time on / Cycle time off |
Duration of the running time and of the pause in cycle
operation, in minutes. The times are only shown while cycle operation is
switched on. |
|
| Maximum run time |
After this time the fan is switched off, even if a demand
is still present. The value 0 switches the limit off. |
|
| Minimum run time |
The fan runs at least this long before it may switch
off. |
|
| Minimum idle time |
The fan stays off at least this long after switching
off. |
|
| Night set-back |
Off, humidity only, or lock completely - valid within the
configured time window. |
|
| Night start / night end |
Time window of the night set-back, each as hour and
minute. If the start is after the end, the window spans midnight. |
|