Assortment / System Description

Fan coil application
Preheating
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17.16 Preheating
The central functions can trigger the preheating function to heat up a room at
end of the night setback period as quickly as possible to the Pre-Comfort
setpoint. This impacts the plant operating mode of the application.
17.17 Emergency mode
The setpoint for protection ensures that room temperatures do not change
below or above a critical limit.
17.18 Night cooling
The plant operating mode cools a room using cooling outside air. The central
function sends a "Night cooling request" to the group member rooms. The
decision as to whether night cooling makes sense and is energy efficient is
made at the central function. Various coordination signals between the primary
plant and room automation do the following via central functions:
● Switch on the fans,
● Set the mixed air dampers to 100% outside air,
● Lock all other equipment including heating coils, cooling coils, humidifier.
Night cooling only occurs under the following conditions:
● The room is vacant (Economy or Protection).
● The outside temperature is above an adjustable setpoint of 9 °C.
● The temperature difference to cooling is sufficiently large, i.e. room
temperature - outside temperature > 7 K.
● The temperature deviation from room temperature and temperature
setpoint is sufficiently large, i.e. room temperature > room setpoint + 2 K.
Description Name Default value
Night cooling
0: Inactive
1: Active
NgtCReq 0: Inactive
17.19 Free cooling
The function free cooling to take advantage of cooling generated without effort
to cool the rooms to a room temperature setpoint. Dew point compensation is
still available for the chilled water temperature setpoint dependent on active
dew point detector via the grouping function.
This supply chain is continued accordingly, in other words chilled water
generation (chillers, refrigeration machines, etc.) are also controlled based on
demand.
17.20 Reset setpoint
The central function can reset a local change to a setpoint on the room
operator unit. The management station can manually reset the value or the
reset can also be automatic by a scheduler. Setpoints for room temperature,
ventilator stage, and room operating mode can be reset.
17.21 Free inputs/outputs
Inputs and outputs can be configured as free inputs on all DXR2s. This permits
the querying of unused input and output switching states or directly controlling
another device over BACnet.