AERMEC VMF-E0X Manuel D'utilisation Et D'installation page 15

12°C) if the ambient temperature falls
below 7°C and the temperature of the
water in the system is suitable.
In the fan coil networks, the Slave fan
coils can activate the anti-freeze pro-
tection regardless of the settings on the
Master fan coil.
If the anti-freeze protection is active on
the Master fan coil, all the other Slave
fan coils will also adopt a set point
of 12°C, regardless of their ambient
conditions.
• Ambient temperature probe
If the ambient temperature probe on the
Slave fan coils is faulty, the temperature
will be measured by the probe of the
Master.
• Ambient probe correction
To obtain a better ambient temperature
adjustment, the thermostat applies
special algorithms to correct the ambi-
ent probe installed on the fan coil; the
probe is in contact with the housing,
and is therefore influenced by it.
The dynamic correction is a correction
algorithm of the ambient probe which
takes into account the particular opera-
tion status of the fan coil in any one
moment. More precisely, there are two
possible cases of dynamic correction:
- Dynamic correction A: in the case
of systems without a valve (or with a
downstream probe), the correction
depends on the water and ambient
temperatures.
- Dynamic correction B: in the case of
systems with a valve and an upstream
probe, the correction depends on the
Valve and on the Water and Ambient
temperatures. Unlike the previous
correction, this one uses different time
constants to calculate the appropriate
correction (because the housing is
influenced in a different way).
• Water probe
There is a water temperature probe in the
heat exchanger of the unit.
The Slave fan coil can work without the
water probe: if it is absent or faulty,
the temperature will be measured by
the Master probe alone. In this case,
ventilation is always enabled on the
Slave fan coil.
The water temperature probe can be
positioned downstream or upstream
from the shutoff valve, so also the dip-
switches on the board must be set. The
difference lies in the management of the
ventilation of the fan coils with valve.
Setting the dip-switch as a downstream
probe of the valve, ventilation start-up
(changeover) is dependent on the tem-
perature of the air in the room.
Setting the dip-switch as an upstream
probe of the valve, ventilation start-up
is dependent on the temperature of the
water in the system. With this setting,
the pre-heating function is activated,
and there is a ventilation start-up delay
of between 0" and 2'40".
To position the bulb on the delivery pipe
upstream of the valve, the standard
water probe must be replaced with the
VMF-SW probe accessory.
• Ventilation
3-speed ventilation can be controlled
both manually and automatically.
- Manual, with the selector in position
V1, V2 and V3. The fan is used with
ON-OFF cycles at the selected speed.
- Automatic, with the selector on AUTO.
The fan speed is managed by the ther-
mostat, on the basis of the ambient con-
ditions and the fan coil configuration.
Thermostat settings:
- 3-level thermostat, With the selector
on AUTO. The fan maintains the speed
relating to one of the three predeter-
mined steps, depending on the differ-
ence between ambient temperature and
set point. Once it has reached the set
point, the fan will switch off.
• Ventilation management
Ventilation settings:
- Continuous ventilation. Ventilation is
always active. The temperature is con-
trolled by intercepting the flow of water
to the fan coil. This function requires the
presence of a water valve (accessory),
and cannot be activated simultaneously
with the "modulated output thermostat"
option.
- Thermostat-controlled ventilation.
Ventilation switches off when the set
temperature is reached (set point).
• Valve adjustment logics
With the Thermostat-controlled ventila-
tion or Modulated output thermostat
setting, the valve is managed with the
following logics:
- Heating - the valve is managed to
exploit the stack effect of the fan coil,
and to provide heat even with the fan
switched off. These settings also reduce
the number of valve openings and clos-
ings; with hot water circulating in the
fan coil, a request from the thermostat
will produce ventilation immediately.
- Cooling - to make the best use of the
unit's cooling capacity and perform a
more accurate check on the ambient
temperature, the valve opening does
not coincide with ventilation.
• External contact
The board offers the possibility of a con-
nection with an external contact. With
a closed external contact, the unit is
configured as in the thermostat OFF
position (except when the thermostat
is in the Anti-freeze Protection position
or when the ambient probe is absent
or faulty). This contact can be used
to manage inputs such as a remote
ON-OFF controlled, a presence sensor,
a window contact, a faulty circulation
pump signal, etc.
In fan coil networks, only the external
contact of the Master fan coil is ena-
bled. If the master input is closed, all
the slave fan coils of the network are
switched off.
• Microswitch contact
The board offers the possibility of a con-
nection with the Microswitch contact
located on the delivery fins. With the
fins closed, the fan coil is 100% OFF.
In fan coil networks, when the fin of the
Master fan coil is closed, ventilation
stops but the electronic thermostat
board and the other fan coils in the
network carry on working. If the DIP
8 is ON, the micro-switch functions as
season changeover, with the contact
being open the thermostat works in
heating mode; if the contact is closed,
the thermostat works in cooling mode.
• Emergency operation
In the event of a faulty ambient probe,
the electronic board can automatically
detect the problem and enable an
emergency program to avoid any
inconvenience for the user, who is
immediately informed of the fault (LED
indicator lights).
• Behaviour with a faulty water
temperature probe
Ventilation is always active.
The season change is made on the
basis of the difference between the
setting made and the actual ambient
temperature.
If the actual ambient temperature exceeds
the Heating set point by a value equal
to the dead band, there is an automatic
swap to Cooling operation.
If the actual ambient temperature falls
below the Cooling set point by a value
equal to the dead band, there is an
automatic swap to Heating operation.
Heater switch-on and switch-off depends
solely on the thermostat operation
request.
In this case, a fixed correction of the
ambient probe is envisaged, and is
determined on the basis of the type of
thermostat configured.
• Behaviour with a faulty ambient
temperature probe
- 2-pipe system:
With the selector in the OFF/Aux
position, ventilation switched off and
the valve is closed
With the selector in the AUTO, V1,
V2, V3 position, the Heating mode is
fixed and the valve is always open.
The ventilation makes on-off cycles
of variable duration depending on the
position of the temperature selector.
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