Applicatio Manual
Universal Interface 4 DIN/NTC EK- CG2-TP
Revisione 1.0.0 - Aggiornato: 04/09/2017
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MAEKCG2TP_EN
Pag. 66
Fan manual active status
1 Bit
CRWTU-
[1.011] state
53
Fan manual speed percentage
1 Byte
CR-T--
[5.001] percentage
75
Fan manual speed off status
1 Bit
CR-T--
[1.011] state
76
9.7.2
Delayed fan start (“hot-start”)
This function is used in case the fan forces in the room air passing through a heat exchange coil (as in the case of the
terminals to the fan-coil). In the heating mode of operation, to avoid possible discomfort caused by the dispatch of cold
air in the room, the room temperature controller does not start the fan until the fluid has not reached a sufficiently high
temperature. This situation normally occurs at the first start or after long periods of inactivity. The function can be carried
out by:
1.
a temperature control (through a temperature sensor on the coil exchange battery);
2.
a delayed start (function approximated);
In the first case the temperature of the heat conveying fluid is acquired at the exchange battery. The function then has
an effective temperature control, but for the execution is necessary that the heat exchange coil is equipped with a sensor
of minimum water temperature that acquires the temperature of the heat conveying fluid.
The effectiveness of the function depends on a field measurement of the time actually required to have sufficiently warm
air from the terminal.
9.7.3 Antistratification function
This function is used in the case of heating systems with thermal exchange of convective type for rooms with height and
volume much higher than usual (atriums, fitness facility, commercial buildings, etc.). Because of the natural convection
- with warm air rising to the highest altitudes of the room - the phenomenon of air stratification occurs, with energy waste
and discomfort for the occupants at the same time. The function opposes to the air stratification, forcing the warm air
downwards.
The antistratification function requires:
•
rooms of great height;
•
availability of ventilation devices able to force the air movement downwards (opposed to the natural convective
movement of warm air);
•
measuring of the temperature at two heights through the installation of a second temperature sensor at an
adequate height in order to measure the actual air stratification (the main room temperature controller is
supposed to be installed at 1.5 m).
For rooms with ordinary height (2,70÷3,00 m) the DIN 1946 standard recommends not to exceed 2 K/m in order to have
an adequate comfort; this gradient may be bigger in higher rooms.
9.7.4 2-stage configuration with fan-coils as auxiliary stage
The fan-coil units may be used both as a main stage and secondary stage. As main stage they can be combined only to
radiators as auxiliary stage. If, however, the main stage is done with (floor or ceiling) radiant panels, the fan-coils can be
used as auxiliary stage. In the latter case they work in automatic mode with a configurable offset with respect to the
temperature setpoint for the main stage, and then carry out their compensation function while the main stage is brought
in temperature with bigger inertia.
