Zehnder EASY 5.0
14
When the function is activated, the machine goes through a stop and start phase. It then starts a phase of 180 seconds
(adjustable) during which the unit operates with the cooling parameters set (normal operation fan se offset if
present) in order to properly irrigate the temperature sensors and ensure that the measured values are stabilised and
reflect the current situation.
Once this has finished, the shutdown conditions are checked. If at least one of the following conditions exists, then the
unit quits the cooling function:
■
The outdoor temperature is outside the permitted range:
Outdoor temperature > 35°C
Outdoor temperature <14°C
■
The return air temperature is below the specified value (18°C)
■
Normal operation, external forced operation and restart must be off (not active)
■
The difference between the return air temperature and the outdoor temperature is sufficient (2°C adjustable)
■
The end time (07:00) has been exceeded.
When night cooling has been activated, the heating outputs are deactivated 180 minutes (adjustable) after the night
cooling function has been exited, in order not to lose the accumulated energy and comfort benefits.
Example: heating can only be switched on from 08:00 if cooling was stopped at 05:00, although the end time is set to
07:00.
If the activation conditions are met again, the fan offset will only be active after a time limit of 60 minutes from the time
the cooling function was exited.
When cooling is active:
■
The DO output cooling (NO) is closed. This change of state must be used to force open any registers placed on the air
distribution network (LOBBY constant pressure network)
■
The normal operation fan setpoint is used and an adjustable offset (positive or negative) is applied if this is set.
10. Anti-icing function by reducing the air volume
By reducing the air volume in the supply air stream, this function prevents the temperature of the return air stream from
dropping too low, which could lead to the icing of its water vapour and thus the clogging of the exchanger.
This function can be considered when the building is heated mainly by generators whose energy cost is cheaper than if
an electric Joule heat exchanger is used to preheat the fresh air, or when there are power supply/power constraints. In
effect, the function limits the electrical power consumed by the machine, which is particularly useful in certain countries
or regions during the winter.
Access path to the function (Access level: Expert)
Step 1
→
Step 2
→
Step 3
→
Step 4
From
screen
Area to
click
Functions
Protection against icing
Settings and configuration
Sensors
Alarms
PID loops
Functions
Actuators
Main menu
Function settings
Protection against icing
Protection against fire
Forced operation
Cooling
Cold recovery
Z-MASTER-V1122-CSY-INM-Zehnder Easy5.0
