FL 24 MCS
Room temperature adjustment (with optional room thermostat)
Using the room thermostat, set the temperature required in the rooms. If the room ther-
mostat is not installed, the boiler will keep the system at the set system delivery setpoint
temperature.
Room temperature adjustment (with optional remote timer control)
Using the remote timer control, set the required temperature in the rooms. The boiler will
adjust the system water according to the required room temperature. For operation with
remote timer control, please refer to the relevant instruction manual.
ECO/COMFORT selection
The unit has a function that ensures a high domestic hot water delivery speed and max-
imum comfort for the user. When the device is activated (COMFORT mode), the water
contained in the boiler is kept hot, thereby ensuring immediate availability of hot water
on opening the tap, without waiting times.
The user can deactivate the device (ECO mode) by pressing the eco/comfort button
(detail 7 - fig. 1). In ECO mode the display activates the ECO symbol (detail 12 - fig. 1).
To activate the COMFORT mode, press the eco/comfort button (detail 7 - fig. 1) again.
Sliding Temperature
When the optional external probe is installed, the boiler adjustment system works with
"Sliding Temperature". In this mode, the temperature of the heating system is controlled
according to the outside weather conditions, to ensure high comfort and energy saving
throughout the year. In particular, the system delivery temperature is decreased as the
outside temperature increases, according to a specific "compensation curve".
With Sliding Temperature adjustment, the temperature set with the heating buttons (de-
tail 3 - fig. 1) becomes the maximum system delivery temperature. It is advisable to set
a maximum value to allow system adjustment throughout its useful operating range.
The boiler must be adjusted at the time of installation by qualified personnel. Possible
adjustments can in any case be made by the user to improve comfort.
Compensation curve and curve offset
Press the reset button (detail 6 - fig. 1) for 5 seconds to access the "Sliding temperature"
menu; the display shows "CU" flashing.
Use the DHW buttons (detail 1 - fig. 1) to adjust the curve from 1 to 10 according to the
characteristic. By setting the curve to 0, sliding temperature adjustment is disabled.
Press the heating buttons (detail 3 - fig. 1) to access parallel curve offset; the display
shows "OF" flashing. Use the DHW buttons (detail 1 - fig. 1) to adjust the parallel curve
offset according to the characteristic (fig. 6).
Press the reset button (detail 6 - fig. 1) again for 5 seconds to exit the "Sliding Temper-
ature" menu.
If the room temperature is lower than the required value, it is advisable to set a higher
order curve and vice versa. Proceed by increasing or decreasing in steps of one and
check the result in the room.
OFFSET = 20
90
10
9
8
7
85
6
80
5
70
4
60
3
50
2
40
1
30
20
fig. 6 - Example of compensation parallel curve offset
Adjustments from Remote Timer Control
If the Remote Timer Control (optional) is connected to the boiler, the above ad-
A
justments are managed according to that given in table 1.
Table. 1
Heating temperature setting
DHW temperature adjustment
Summer/Winter Switchover
Eco/Comfort selection
Sliding Temperature
OFFSET = 40
90
10
9
8
7
85
80
70
60
50
40
30
20
Adjustment can be made from the Remote Timer Control menu
and the boiler control panel.
Adjustment can be made from the Remote Timer Control menu
and the boiler control panel.
Summer mode has priority over a possible Remote Timer Control
heating demand.
On disabling DHW from the Remote Timer Control menu, the
boiler selects the Economy mode. In this condition, the eco/com-
fort button (detail 7 - fig. 1) on the boiler panel is disabled.
On enabling DHW from the Remote Timer Control menu, the
boiler selects the Comfort mode. In this condition it is possible
select one of the two modes with the eco/comfort button (detail 7
- fig. 1) on the boiler panel.
Both the Remote Timer Control and the boiler card manage Slid-
ing Temperature adjustment: the boiler card Sliding Temperature
has priority.
cod. 3541F121 - Rev. 01 - 03/2018
System water pressure adjustment
The filling pressure with system cold, read on boiler water gauge (detail 17 - fig. 1), must
be approx. 1.0 bar. If the system pressure falls to values below minimum, the boiler stops
and fault F37 is displayed. Operate the filling cock detail 1 fig. 7 and bring it to the initial
value. Always close the filling cock at the end of the operation.
3. INSTALLATION
3.1 General Instructions
BOILER INSTALLATION MUST ONLY BE PERFORMED BY QUALIFIED PERSONNEL, IN AC-
CORDANCE WITH ALL THE INSTRUCTIONS GIVEN IN THIS TECHNICAL MANUAL, THE
PROVISIONS OF CURRENT LAW, THE PRESCRIPTIONS OF NATIONAL AND LOCAL STAND-
ARDS AND THE RULES OF PROPER WORKMANSHIP.
3.2 Place of installation
The combustion circuit is sealed with respect to the place of installation, therefore the unit can be
installed in any room. However, the place of installation must be sufficiently ventilated to prevent
the creation of dangerous conditions in case of even small gas leaks. This safety standard is re-
quired by the EEC Directive no. 2009/142 for all gas units, including those with sealed chamber
The unit is suitable for operation in a partially protected place in compliance with EN 297 pr A6, for
temperatures to -5°C. It is advisable to install the boiler under the slope of a roof, inside a balcony
or in a sheltered recess.
Therefore the place of installation must be free of dust, flammable materials or objects or corrosive
gases.
The boiler is arranged for wall mounting and comes standard with a hooking bracket. Fix the brack-
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5
et to the wall according to the measurements given in the cover drawing and hook the boiler on it.
4
A metal template for marking the drilling points on the wall is available by request. The wall fixing
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must ensure stable and effective support for the generator.
2
If the unit is enclosed in a cabinet or mounted alongside, a space must be provided for
A
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removing the casing and for normal maintenance operations
3.3 Plumbing connections
Important
B
The safety valve outlet must be connected to a funnel or collection pipe to pre-
vent water spurting onto the floor in case of overpressure in the heating circuit.
Otherwise, if the discharge valve cuts in and floods the room, the boiler manu-
facturer cannot be held liable.
B
Before making the connection, check that the unit is arranged for operation with
the type of fuel available and carefully clean all the system pipes.
Carry out the relevant connections according to the cover diagram and the symbols giv-
en on the unit.
Note: The unit has an internal bypass in the heating circuit.
Water system characteristics
In the presence of water harder than 25° Fr (1°F = 10ppm CaCO
water in order to avoid possible scaling in the boiler.
Antifreeze system, antifreeze fluids, additives and inhibitors
When necessary, antifreeze fluids, additives and inhibitors can be used only if the man-
ufacturer of such fluids or additives guarantees that they are suitable and do not cause
damage to the exchanger or other components and/or materials of the boiler and system.
Do not use generic antifreeze fluids, additives or inhibitors that are not specific for use in
heating systems and compatible with the materials of the boiler and system.
3.4 Gas connection
The gas must be connected to the relevant union (see figure on cover) in conformity with
the current regulations, with a rigid metal pipe or with a continuous surface flexible s/steel
tube, installing a gas cock between the system and boiler. Make sure all the gas connec-
tions are tight.
3.5 Electrical connections
Important
B
The unit must be connected to an efficient earthing system in conformity with
current safety regulations. Have the efficiency and suitability of the earthing
system checked by professionally qualified personnel; the Manufacturer de-
clines any liability for damage caused by failure to earth the system.
The boiler is prewired and provided with a "Y" type cable (without plug) for con-
nection to the electric line. The connections to the power supply must be per-
manent and equipped with a double-pole switch with contact opening distance
of at least 3 mm, installing fuses of max. 3A between the boiler and the line.
Make sure to respect the polarities (LINE: brown wire / NEUTRAL: blue wire /
EARTH: yellow/green wire) in connections to the electric line.
B
The unit's power cable must not be replaced by the user; if damaged, switch
the unit off and have the cable replaced by professionally qualified personnel.
If replacing the power cable, only use "HAR H05 VV-F" 3x0.75 mm2 cable with
max. ext. diameter of 8 mm.
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fig. 7 - Filling cock
), use suitably treated
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EN
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