CORRIGO VENTILATION 3.6 MANU

Manual Corrigo Ventilation, revision V Chapter 5 Functional description 41
5.1.11 Recirculation
Recirculation is a function for distributing the air in the room using the supply air fan. The function
can be used even when there is no heating or cooling demand. When using recirculation control, the
extract air fan stops (but can also be set to run) and a recirculation damper opens which allows the air
to circulate through the unit.
Recirculation is activated either via a digital input signal or by connecting it to "Timer output 5". If
timer output for normal/reduced speed is activated during recirculation via ”Timer output 5”,
normal/reduced speed gets priority. If timer output for normal/reduced speed is activated during
recirculation via a digital input, recirculation gets priority.
Either a digital output (Recirculation damper) or an analogue output (Y4 Extra sequence) can be used
as an output signal. When Y4 Extra sequence is used, the damper will become modulating.
Recirculation control can be configured as either air circulation (temperature control inactive) or air
circulation with temperature control. (Only heating, only cooling or both heating and cooling).
Recirculation control has its own setpoint. However, the other settings are the same as for normal
operation, i. e. if normal operation has been configured as room control, room control will also be
used during recirculation.
The recirculation setpoint can be configured as constant or offset. Constant means that the
recirculation setpoint will be used. Offset is based on an offset from the supply air setpoint.
To lower the temperature, it is possible to configure free cooling to be used during recirculation, if
the conditions for free cooling are fulfilled. Then, the recirculation damper closes, the supply and
extract air dampers open and the extract air fan starts (the supply air fan also starts, if it is not already
running). If the free cooling function is not configured for recirculation control and you want to cool
down the supply air via a low recirculation setpoint, the cooling battery will be used. A max. room
temperature can be configured for recirculation control. If the room temperature rises above the set
value (FS 25°C), recirculation will be stopped. When the room temperature has fallen 1 K below the
set max limit, recirculation will start again if the start conditions are still fulfilled.
When running frequency controlled fans and using recirculation control you can, depending on the
type of fan control, configure a special pressure/flow offset for the setpoint or a manual output signal
for the supply air fan.
5.1.12 Change-over
Change-over is a function for installations with 2-pipe systems. It makes it possible to use the same
pipe for both heating and cooling, depending on whether heating or cooling is required.
A special analogue output signal, "Y1 heating/Y3 cooling", is used for Change-over control.
Switching between heating and cooling can be done in two ways. A digital Change-over input signal
is normally used. Open contact gives heating control and closed contact gives cooling control. If the
input has not been configured, change-over is handled by the internal controller signal. The output
signal will follow the two regular output signals "Y1 heating" and "Y3 cooling". For heating control,
the digital outputs ”Heating activate” and ”Heat step 1-4” are active. For cooling control ”Cooling
activate” and ”Cool step 1-3” are active.
If frost protection sensor has been configured, it will function in the usual way when heating is active.
However, when cooling is active, it will only be used for indicating temperature.
Three digital output signals, "Heat/Cool Step 1", "Heat/Cool Step 2" and "Heat/Cool Step 3", are also
connected with change-over. The signals can be used for reversing a step controlled heating pump
etc. See also section 5.1.4 Step controller Heating/ DX cooling.
The change-over function can be split if needed. If so, set the analogue output to “Split” and select
the function Y1 heating/Y3 cooling.
A digital function called “Split sequence” is connected to the split signal. It is active when the
corresponding analogue signal exceeds 0.1 V.