Thermal valve actuators
Chilled ceiling (CLC01)
The chilled ceiling application has a continuous cooling sequence. The room controllers
operate with a PI algorithm optimized for thermal or motorized valve actuators. (For
simplicity, the diagram below only shows the P-control action.)
The control sequence comes into operation at the effective setpoints for cooling (see
Select actuator types for chilled ceiling
See section 8.1.1 , page 79 on selecting actuator types for radiators.
The following information differs from the radiator applications:
Actuat c'surf valve
• If thermal actuators are selected, Y3 / Y4 are always controlled in parallel to ensure
that several actuators can be connected at the same time.
• Exact parallel operation of several thermal valve actuators is not guaranteed. If
several radiators are controlled by the same controller, motorized actuators are the
If nevertheless thermal actuators are controlled in parallel, "3rd Party Thermic" must
be parameterized regardless of make.
• Thermal actuators work at higher temperatures. To ensure a fast reaction, the
actuators are slightly preheated continuously (5% – 1 sec ON / 19 sec OFF). Then
thus also receive pulses from the controller when closed.
RXB (KNX) Applications library
Effective cooling setpoint
CLC and RAD description of functions for CC-02 CM110384en_03
28 Feb 2009