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4A
42WMx09C----- 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.
42WMx09C----- fan coils include an electronic control and supervision board that manages their operation, assuring
the best indoor comfort.
42WMx09C----- 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.
42WMx09C----- 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.
42WMx09C----- 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. Venti-
lation 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:
STATUS
LED
RED
LED
GREEN
OFF
ON
Blink
OFF
ON
Blink
OFF
X
X
ON
X
X
ON and T3 not satisfied
X (*)
X
Probes error (T1-T2-T3)
X
T3 > 70 °C
X
X
Open window contact
X (**)
X
Active pump alarm or more alarms activated
X
X
(*)
Low bright intensity Red LED power-On
(**)
Double flashing