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41. SELECTION CRITERIA
The VED_I_US wall-ceiling mounted fan
coils are suitable for both vertical and hor-
izontal ducted installations.
VED_I_US is designed to operate at the 3
default speeds described in the manual.
In case of ducted installations, where the
duct pressure drops are significant, the
VED_I_US version allows obtaining the
necessary static pressure to ensure proper
air flow rate by modifying the settings of
the connections on the electrical box on
the motor. VED_I_US enables you to select
3 speeds among the 5 speeds available on
the motor.
All versions must be combined with a con-
trol panel (accessory), refer to the fea-
tures and the compatibility of the control
panels supplied as accessory.
Several accessories are available for
VED_I_US series fan coils, sometimes they
cannot be overlapped. The compatibility
of the accessories with the selected fan
coil must be checked. The manual gives
the description, a diagram and compatibil-
ity of each accessory.
The information regarding installation
is inserted in the manuals accompany-
ing each fan coil and each accessory. This
manual gives general information for good
installation. It also gives diagrams with
dimensions of the fan coils and wiring dia-
grams with connection to control panels.
The main technical data for the VED_I_US
fan coils is summarised in the tables.
The sensitive and total cooling yields at
maximum speed depending on the tem-
perature of the water entering, of its heat
drop and temperature of the air with dry
bulb and wet bulb respectively for sensi-
tive capacity and total cooling capacity
are stated in the table and are referred to
the maximum speed. The performance at
medium and minimum speed are obtained
by multiplying the values in the table by
the corrective factors indicated.
The pressure drops on the water side,
respectively for 3 - 4-row coils (heating
and cooling) and 1 - 2-row coils (heating
only) are shown in the charts.
The correction factors in functioning with
glycol water in cooling and heating modes
are stated in the graphics per percentages
of glycol of 10%, 20% and 35%.
The heating capacity produced by the 3
- 4-row coils and 1 - 2-row coils, depend-
ing on the water flow rate and the tem-
perature difference between the incoming
water and incoming air, is specified graphi-
cally and refers to the maximum speed.
The performance at medium and mini-
mum speeds are obtained by multiplying
the values from the charts at maximum
speed by the corrective factors indicated.
The sound pressure and power level of the
fan coils at the various speeds is stated in
separate tables.
For the ducted installations the sound
power level is expressed in terms of air
flow rate and static pressure and is repre-
sented by graphics.
The static pressure of the wall/ceiling
mounted versions based on the air flow
rate and fan speed, are shown in table
form, the curves are indicated for each of
the speeds of reference.
For the sizing of the ducted suspended
version it is recommended to proceed as
follows: choose a size which, in rated flow
conditions, has a capacity immediately
higher than that required; draw the pres-
sure drops curve of the duct on the flow
rate-static pressure diagram related to
the current unit, thus locating the opera-
tion points of the unit at different speeds.
Based on the flow rate values correspond-
ing to the above-mentioned points, obtain
the correction factors that allow you to
calculate the capacity in the actual air flow
rate conditions.
The above procedure allows choosing
whether to modify the motor connections
settings.
