Heating and Cooling

Automatic Changeover

If you select the Automatic changeover between Heating and Cooling, the controller decides which mode is suitable based on the parametrized setpoints, the insensitive zone and the current actual temperature.

If you select the external switchover using Heating/cooling mode object, the controller can only be forced into heating or cooling mode by the object value.

Dead Zone

The insensitive zone prevents the controller from switching frequently between heating and cooling. For example, if a heater is used for heating, it has sufficient thermal energy after the valve has been closed to continue to heat the room above the setpoint temperature.

Example:

If you have project the same value for the heating and cooling setpoints, the insensitive zone is set to "0 K". After a delay time that can be set has elapsed, the air conditioning system cools because the setpoint for cooling has been exceeded. If there is a short delay time, the controller switches the controller mode particularly frequently.

Make sure that the heating setpoint is always less than the cooling setpoint.

Status after Power on/Download

You define the mode to which the controller changes after download (Heating or Cooling) or reset (Heating/Cooling/As before voltage failure).

2-Pipe/4-Pipe HC System

Finally, you choose between a 2-pipe and a 4-pipe system.

In the 2-pipe system, heating and cooling mediums (depending on the season) are lead through the same lines and controlled via the same valve.

A Cooling supply

B Heating supply

C Cooling return

D Heating return

A Cooling supply

B Heating supply

C Cooling return

D Heating return

The changeover between heating and cooling medium is performed by the system, and must therefore be passed on to the controller.

The Heating/cooling mode object sends “0” for heating mode and a 1 for cooling mode to the actuator.