Zehnder EASY 5.0
65
The feedback from the heat exchanger uses the normally open NO output DIG RELAY OUT (wired between (9) and (10)).
When there is a fault, the contact remains open and closes if the wheel is working properly.
27. Control of the plate heat exchanger
27.1. General
The performance of the plate heat exchanger is continuously adjusted through the use of a bypass flap placed on the
fresh air stream.
When the need for heat recovery is greatest, the bypass is closed and forces the entire fresh air volume through the
exchanger to transfer/recover energy to the return air. Conversely, when there is no need for heat recovery (free cooling
or, more rarely, free heating), the bypass is opened, thus diverting the fresh air volume from the exchanger.
The bypass operates when there is:
■
A need to modulate heat recovery, which is the case when:
There is a heating requirement and the return air temperature is higher than the fresh air temperature (the fresh air is
possibly preheated to -5°C)
There is a cooling requirement and the extraction temperature is lower than the fresh air temperature
■
A risk of the heat exchanger icing up. In this case, the heat recovery modulation is no longer active and the anti-icing
protection takes priority.
Access path to the function (Access level: Expert)
Step 1
→
Step 2
→
Step 3
→
Step 4
From
screen
Area to
click
Actuators
Bypass exchanger
Settings and configuration
Sensors
Alarms
PID loops
Functions
Actuators
Actuator settings 2/2
Cooling
Bypass exchanger
Electric heating coil
Electric preheating coil
Main menu
Z-MASTER-V1122-CSY-INM-Zehnder Easy5.0
1: GND
2: 0-10V
3: A
4: B
5: GND
6: +12V
7: DI3
8: RL_NC
9: RL_C
10: RL_NO
11: GND
12: DI2
13: GND
14: DI1
DIG.RELAY OUT
