Swegon CLASS UNIT Operation & Maintenance Instructions Manual page 42

7.22 TYPE 20: ALARM INDICATING THAT THE DEFROST PROCESS IS ACTIVE
- Conditions:
• Unit with counter flow heat exchanger
- Causes:
• The ice forming inside of the plate heat exchanger is genrating a pressure drop that is to high for the current airflow.
This detection requires a Modbus pressure sensor placed on the heat exchanger and that the modulation
of the fans speed is based on the airflow and not on torque
• When the previous detection is not available, the supply T° is checked and if it falls below 11°C, it is considered
that is due to the ice that reduces the heat exchanger efficiency
- Effects:
A.20 Defrost
AL1 relay
/
7.23 REC TABLE
In the control board the "REC type" is used to define the type
unit. When replacing the control board, the REC type needs to
be configured in the product setup menu. The product setup
menu is used to enable specific features or to modify factory
settings. This must be done by an accredited technician. A
code and special training is mandatory to access this menu
group. The table below is valid for controllers generation TAC.
RANGE SIZE
CLASS UNIT
Unique
42
Displayed on HMI TACtouch
Text displayed
TAC control board
O.R.1 LED ALARM
/
Auto reset: yes
TAC DG
884229
LED AF
ON ON
Operation and maintenance
LED ALARM LED Pa
RED /
Fans
Supply stopped
instructions – CLASS UNIT TAC5