Data Sheet for Product

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Building Technologies Fan coil controller for wall mounting ACR12 CE1N3578en
HVAC Products 03.10.2005
Technical design
The room temperature is measured by an inbuilt sensor and compared to the actual
set-point. According to the resulting deviation, the processor calculates the pulse dura-
tion ratio for controlling the thermal valve actuators and, if necessary, for controlling the
electric heater. In addition, if the selector switch for the fan speed on the controller is
set to "Auto“, the optimum fan speed is defined automatically.
The user can choose between P (proportional) and PI (proportional/integral) controlling
behaviour. These and other settings can be made on the device by either using DIP
switches or the parameter menu, depending on the type of controller.
The P (proportional) bands for the heating and cooling sequences can be defined sepa-
rately between 2 K and 4 K (see switches P05 and P06).
The integral action time I (integral) is 5 minutes (only active if PI control is selected).
The heating and cooling symbols on the display or the appropriate LEDs show in a four
pipe system exactly what is done. The heating symbol is active when the fan-coil is
heating and the cooling symbol when it is cooling. In neutral zone the symbols are
switched off.
In a two pipe system these symbols show in general what the status of the fan-coil is
(what it can do). This means, the symbols are also shown in the neutral zone. However
there is an exception: If the changeover is on cooling and the electric heater is on, then
the heating symbol is active. However as soon as the neutral zone is reached, the cool-
ing symbol is shown again if this is still the actual status of the fan-coil.
Set-points
In comfort operation, the set-points are either defined at the factory (for controllers
without a display) or are defined in the parameter mode. The heating set-point is nor-
mally set to 20 °C and the cooling set-point to 23 °C. The room user can adjust the set-
points by maximum ± 6 K (Kelvin) or what is defined by P15. This produces a maximum
set-point range for the default set-points of 14...26 °C in heating operation and 17...29
°C in cooling operation. The neutral zone remains constant at 3 K in this example.
The minimum possible neutral zone is 2K.
In economy operation, the set-points are fixed at 14 °C for heating and 30 °C for cool-
ing and cannot be changed with the room units.
However if the economy operation is defined as the normal mode and not as the re-
duced mode (P01 = 1 or ON) then the offset shift is active for the economy set-points.
This produces a set-point range of 8…20°C for heating and 24…36°C for cooling op-
eration. The neutral zone remains constant at 16K.
In standby operation, the set-point of the controller is permanently set to 8°C heating
Adjustments are prohibited, due to the regulations of some countries. Cooling operation
is not possible.
Controller
Display