Dantherm Vent R2 - Heat Recovery; Reheater Coil; Cooling at Summer Nights

STXC2 User’s guide
Version 2.0
27 of 30
3.2.1 Heat recovery.
In an air-to-air plate heat exchanger the By-pass damper takes 10% (hysteresis) of the P-band
between heating mode and cooling mode (more fresh air for cooling).
When heating is needed, the bypass damper closes by pulsing (runs slowly). When cooling is
needed, the bypass damper opens by pulsing. If the outside temperature is higher than the return air
temperature, the bypass damper will not open.
The heat wheel heat recovery works the same way as the bypass damper and takes 10% of the P-
band between heating mode and cooling mode. The function is linear.
If more heat is required, the heat wheel speed increases (2-10V output signal rises). When the heat
requirement reduces, the heat-wheel speed decreases.
3.2.2 Reheater coil.
The active part of the temperature control is a plug connection on the ventilation unit, where a re-
heater coil can be connected (electrical heating coil or LPHW coil).
A reheater coil is controlled by a 2-10V signal.
3.2.3 Cooling at summer nights.
The function cooling at summer nights is used for cooling the room in the summer period.
The most suitable period to use the function cooling at summer nights is at night or early in the
morning before the ventilation requirement is turned on.
When the week program permit the function cooling at summer nights, the ventilation unit starts up
if there haven’t been need of heating in the last running period.
The ventilation unit starts up slowly and 3 minutes later the room/return and ambient temperature is
measured. If the following conditions for the function cooling at summer nights are present, the
ventilation unit continues to run. Else the ventilation unit stops.
Conditions for the function cooling at summer nights:
The measured room/return temperature must be higher than the temperature set point +2°C.
The measured ambient temperature must be lower than the room/return temperature -2°C.
See example on week program using the function cooling at summer nights, chapter 2.6.1 Example
of setting a week program.