6.3. Cooling / heating mode changeover
Cooling / heating mode can be switched by:
Digital input
o Open= Summer
o Close= Winter
Remote keyboard
BMS via Modbus
Automatically with fresh air sensor:
If Te < = Winter mode (heating)
o
If Te > + = Summer mode (cooling)
o
(password) 1
Fresh air temperature set point for automatic changeover
Season changeover differential
6.4. Water coil antifreeze
Here are the parameters to enable the frost sensor:
(password) 1
(Enable antifreeze)
no – yes*
(password) 1
(set antifreeze)
Set point antifreeze
The antifreeze is managed using the supply air temperature (BTM).
Alarm and error active only in heating mode, if electric preheater is installed on the unit it is activate for a set period
to try to increase the temperature before entering in alarm condition.
When the antifreeze alarm is active the fans are Off, the dampers closed, the valve opened.
In case of antifreeze sensor fault:
When the unit is in stand-by the valves opens in the fresh air temperature is lower than antifreeze set point
6.5. Defrost
Defrost management is done by the exhaust air temperature sensor.
To enable a defrost strategy at least one of the following devices have to be available:
Electrical pre-heater
Inverter modulating fans
Here under the path of the parameter to enable the defrost:
(password) 1
firmware 0.26
Electronic Control "HRH-HRS" User Manual
5.0°C
Heating
Te = Air fresh temperature
15.0°C
10.0°C
Rev.06
Cooling
ENG
Te
EN 18/ 23