Zehnder EASY 5.0
15
It should be noted that stopping/reducing the supply air volume and maintaining the return air volume at the nominal
value requires fresh air inlets at the windows (or any other similar device) in order to control the pressure in the building
and the minimum air volume at the return.
This function is activated when the 2 conditions below are met:
■
The anti-icing sequence by bypassing the fresh air volume (see XXVII.3 Protecting the plate heat exchanger against
icing) is active
■
The measured outdoor temperature is below the set threshold (-100°C factory setting, configurable value).
When the function is active, the supply air fan setpoint changes to the minimum signal value of 25% (2.5V, not
adjustable) regardless of the fan control type (ECO/DIVA/LOBBY/MAC2/QUATTRO).
To allow the supply air fan to resume normal operation, the fresh air temperature must return to above the set threshold
(+1°C) AND the fresh air bypass anti-icing function must be reset. This does not always happen instantly depending on
the PID settings.
The factory setting of the outdoor activation temperature threshold is -100°C, which makes this function inactive. To
activate it, it is necessary to change this value to about -10°C.
It is not recommended to activate this function on SMART or INFINITE machines equipped with an electric fresh air
preheating coil. This is because the fresh air volume becomes low (fan control signal at minimum) when the function is
activated, which could lead to overheating of the fresh air preheating coil.
= Possible
= Not recommended
— = Non-functional
If an electric heating coil is integrated in the machine, it will be deactivated for as long as the function is active in order
to avoid excessive overheating of the heating element and its immediate vicinity.
This function is not used in machines with a rotary heat exchanger.
Fan control
Exchanger type
Heating coil type
Thermal control
ECO
LOBBY
MAC2
DIVA
QUATTRO PLAQUE
ROUE
BE
BC
SMART/INFINITE
(Fresh air preheating
coil)
—
Z-MASTER-V1122-CSY-INM-Zehnder Easy5.0