WFS-IR and WFS-MB units are fan coils for wall installation intended for air conditioning of residential and commercial
premises.
The unit includes a fan, which has the purpose of moving air, and a heat exchanger, inside of which hot or cold water
must be circulated, produced by an external generator, boiler, chiller or heat pump.
WFS-IR and WFS-MB fan coils include an electronic control and supervision board that manages their operation,
assuring the best indoor comfort. Specifically, MB versions may be connected to a supervision network or a display
control, T-MB, to be installed on the wall. The control makes it possible to set operating modes while reading room
temperature through a sensor built into the control.
On the other hand, WFS-IR versions are controlled by a remote control with display, which lets you set the operating
modes. For these versions, the air temperature sensor is inserted inside the unit underneath the air filter. Air circulation
is therefore functional to correctly reading the room temperature.
WFS-IR versions are also fitted with a sensor that detects the temperature of the fluid circulating inside the coils and, by
changing the settings of the control board, it is possible to use this sensor to prevent fan operation when the temperature
of the water circulating inside the coil is not sufficiently high, a typical situation that may occur in winter is that the boiler
is off. In this case the failure to circulate hot water prevents correct operation of the fan coil. An appropriate red warning
light alerts the user that the unit is not working, not because it is faulty, but because there is no hot water circulating
to be able to heat, or cold water to cool the room.
WFS-IR versions, with the air sensor located inside the unit, need a special cycle, called anti-stratification cycle,
required to sensitise the air temperature sensor. As a matter of fact, when the temperature setting is reached the fan
stops and, for models fitted with valve, water circulation is shut off. The cycle is activated every 18 minutes and consists
of starting fan operation so that air circulates in the room and in the unit, so as to assess the actual room temperature.
Ventilation is started only if hot water is available, otherwise the unit remains off pending the next cycle. The lack
of hot water in the circuit is signalled by the red LED at the bottom of the unit turning on, this is very dim in order
not to be distracting as it is not an alarm. To prevent discomfort during the night, when the boiler is turned off hence
there is no hot water available, it is recommended to use the timer function for automatic unit switch-on and off,
by setting a switch-off time, at the same time as the boiler switches off, and a switch-on time of 30 minutes later than
the boiler's switching-on time.
The anti-stratification cycle is also activated the first time the heating mode is set up, as well as every time the setting
is modified.
It is possible to check the operating status of the fan coil from the signalling LEDs found at the bottom right of the
unit:
ON and T3 not satisfied
Probes error (T1-T2-T3)
Open window contact
Active pump alarm or more alarms activated
(*)
Low bright intensity Red LED power-On
UNT-SVU014E-XX
STATUS
OFF
ON
T3 > 70°C
LED
RED
OFF
ON
Blink
X
X
X (*)
X
X2
X
LED
GREEN
OFF
ON
Blink
X
X
X
X
X
X
X
5
