Fer FERSYSTEM TECH 31 C Troubleshooting guide

FERSYSTEM TECH 31 C
INSTRUCTIONS FOR USE INSTALLATION AND MAINTENANCE
cod. 3540U320 - 09/2009 (Rev. 00)

Seasonal Efficiency
(SEDBUK)
band A

FERSYSTEM TECH 31 C
2Cod. 3540U320 - 09/2009 (Rev. 00)
• Read the warnings given in this manual thoroughly.
They provide important information for safe instal-
lation, use and maintenance
• By law the instruction manual must be left with the
end user.
• If the appliance is sold or transferred to another
owner or if the owner moves, leaving the appliance
behind, always ensure that the manual is kept with
the appliance for consultation by the new owner
and /or installer.
• Incorrect installation or poor maintenance absolves
the manufacturer from all liability for damage to
people or property.
• Installation and maintenance must be carried out
in conformity with current legislation, according
to the manufacturer’s instructions and by qualified
personnel.
• Before service or maintenance work is, carried out
isolate the appliance from the mains electricity
supply.
• In the event of malfunction or faulty operation, iso-
late the appliance. Do not attempt to repair or carry
out any other operation on the appliance directly.
Contact qualified personnel only.
• Repairs or the replacement of components must be
carried out exclusively by qualified personnel using
original spare parts only. Failure to respect the above
may compromise the safety of the appliance.
• To guarantee efficient operation, the appliance must
be serviced once a year by a corgi registered engi-
neer.
• The appliance may not be used for purposes other
than those for which it was explicitly designed. Any
other use is considered improper and therefore dan-
gerous.
• Incorrect installation and use or failure to follow the
instructions provided by the manufacturer absolve
the manufacturer from all liability for damage.
• After unpacking, check that thecontents are complete
and undamaged.
• Keep the packaging out of reach of children as it is
potentially hazardous.
• To clean external parts, use a damp cloth moistened
with soapy water if necessary. Avoid using abrasive
cleaning products and solvents.
This symbol indicates “Caution” and is placed next to all safety information.
Strictly follow these instructions in order to avoid danger and damage to persons,
or property.
This symbol calls attention to a note or important information, please read thor-
oughly.
IMPORTANT
• Your "benchmark" Installation, Commissioning and Service Record Log Book is enclosed in the
last pages of this manual. “This record must be completed and left with the end user”.
Fer is a member of the Benchmark initiative and fully supports the aims of the programme.
Benchmark has been introduced to improve the standards of installation and commissioning of
central heating systems in the UK and to encourage the regular servicing of all central heating
systems to ensure safety and efficiency. Please see installation and servicing guidelines.
• "Fer declare that no substances harmful to health are contained in the appliance or used during
the appliance manufacture”.

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FERSYSTEM TECH 31 C
Cod. 3540U320 - 09/2009 (Rev. 00)
1. OPERATING INSTRUCTIONS .................................................................4
1.1 Introduction ............................................................................................................4
1.2 Control panel ..........................................................................................................5
1.3 Turning ON and OFF ..............................................................................................6
1.4 Adjustments ............................................................................................................8
1.5 Maintenance..........................................................................................................11
1.6 Faults.....................................................................................................................11
2. INSTALLATION.....................................................................................12
2.1 General Instructions..............................................................................................12
2.2 Boiler location .......................................................................................................13
2.3 Boiler water connections ......................................................................................14
2.4 Connection to the gas system..............................................................................16
2.5 Electrical Connections ..........................................................................................16
2.6 Flue system ...........................................................................................................18
2.7 Condensate outlet connection .............................................................................23
3. SERVICE AND MAINTENANCE............................................................25
3.1 Adjustments ..........................................................................................................25
3.2 System start-up.....................................................................................................26
3.3 Maintenance..........................................................................................................27
3.4 Troubleshooting....................................................................................................29
4. TECHNICAL CHARACTERISTICS AND DATA.......................................................... 31
4.1 Dimensions and connections ................................................................................31
4.2 General view and main components ....................................................................32
4.3 Hydraulic diagram.................................................................................................33
4.4 Technical data table..............................................................................................34
4.5 Diagrams ...............................................................................................................35
4.6 Wiring diagram .....................................................................................................36
Benchmark ..................................................................................................................38


FERSYSTEM TECH 31 C
4Cod. 3540U320 - 09/2009 (Rev. 00)
1. OPERATING INSTRUCTIONS
1.1 Introduction
Dear Customer,
Thank you for choosing the FERSYSTEM TECH 31 C, a FER wall-mounted boiler of the latest generation,
featuring advanced design and cutting-edge technology.
FERSYSTEM TECH 31 C is a high-efficiency condensing pre-mix appliance for heating and hot water
production with extremely low emissions, running on natural gas or LPG.
The boiler consists of an aluminium laminar heat exchanger providing effective condensation of the
water vapour contained in the flue gases, permitting extremely high efficiency.
Above the heat exchanger, in the boiler, there is a pre-mix burner, with a large ceramic surface, equip-
ped with electronic ignition and ionization flame control, which achieves extremely low emissions while
ensuring high reliability and long life operation.
The boiler is totally room sealed from the installation room: the air needed for combustion is drawn from
outside. The boiler also includes a modulating speed fan, modulating gas valve, pump, expansion vessel,
safety valve, flow sensor, temperature sensors, a safety thermostat and a low water pressure switch.
Thanks to the twin microprocessor control and adjustment system with advanced self-diagnosis, unit
operation is for the most part automatic. The power for heating is automatically governed by the control
system.
The user only has to set the temperature desired inside the home by means of a room thermostat and
appliance temperature control. The adjustment and control system will provide optimum operation
throughout the year.
The display continuously provides information on the unit’s operating status and it is easily possible
to obtain additional information on the sensor temperatures, set-points, etc. or configure them. Any
operating problems associated with the boiler or system is immediately signalled by the display and, if
possible, corrected automatically.

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FERSYSTEM TECH 31 C
Cod. 3540U320 - 09/2009 (Rev. 00)
1.2 Control panel
eco/comfort
reset
1
12
14
11
7
6
5
4
3
2
15 9
13
8
fig. 1
1 = Domestic Hot Water temperature setpoint decreasing push button
2 = Domestic Hot Water temperature setpoint increasing push button
3 = Central Heating water temperature setpoint decreasing push button
4 = Central Heating water temperature setpoint increasing push button
5 = Display LCD
6 = Reset / OTC push button
7 = Economy-Comfort / On-Off push button
8 = Domestic Hot Water symbol
9 = Domestic Hot Water mode operation
11 = Multi-function indication (Flashing during heat exchanger protection)
12 = Economy symbol
13 = Central Heating mode operation
14 = Central Heating symbol
15 = Burner on and actual load indication (Flashing during flame current supervision)
Indication during boiler operation
Central Heating mode
The Central Heating heat demand (generated by the OpenTherm Remote Control, the Room Thermostat
or the Clock) is indicated by the flashing of the Hot Air symbol over the radiator (part. 13 and 14 – fig.
1). The display indicates the actual Central Heating water temperature (part. 11 – fig. 1) and during
central heating off time the text “d2”.
fig. 2
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FERSYSTEM TECH 31 C
6Cod. 3540U320 - 09/2009 (Rev. 00)
Domestic Hot Water mode
The Domestic Hot Water heat demand (generated by the DHW flow sensor or due to a Comfort request)
is indicated by the flashing of the Hot Water symbol under the tap (part. 8 and 9 – fig. 1). The display
indicates the actual Domestic Hot Water temperature (part. 11 – fig. 1) and during domestic hot water
off time the text “d1”.
1.3 Turning ON and OFF
Without main power supply
To avoid damage caused by freezing during long shutdowns in winter, it is advisable to drain all
water from the system.
Ignition
Ensure the power is on to the appliance.
For the firsts 120 seconds, the display shows FH that identifies the Air purge function.
During the first 5 seconds, the display shows the software version of the pcb.
Open the gas cock on the boiler and purge the air from the pipework upstream of the gas valve.
When the FH disappears, the boiler is ready to function automatically whenever the external controls
•
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•
•
fig. 3
eco/comfort
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fig. 4 - Boiler without main power supply
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eco/comfort
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fig. 5 Ignition fig. 6 Air purge
eco/comfort
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FERSYSTEM TECH 31 C
Cod. 3540U320 - 09/2009 (Rev. 00)
are calling for heat.
Turning off
Press the (part. 7 - fig. 1) for 5 seconds.
When the boiler is turned off with this key, the p.c.b is still powered, heating operation is disabled and
the display is off however the frost protection will still be active.
To totally isolate close the gas cock ahead of the boiler and disconnect electrical power.
To avoid damage caused by freezing during long shutdowns in winter, it is advisable to drain all
water from the system.
To turn boiler on again, press (part.7 - fig.1) for 5 seconds.
The boiler is ready to function automatically whenever the external controls are calling for heat.
eco/comfort
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fig. 7 - Turning off
fig. 8
eco/comfort
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FERSYSTEM TECH 31 C
8Cod. 3540U320 - 09/2009 (Rev. 00)
1.4 Adjustments
Heating temperature setting
To set the system flow temperature, use the CH push buttons (Part. 3 and 4 – fig. 1). It can be
varied from a minimum of 20°C to a maximum of 90°C.
Domestic hot water temperature setting
To set the hot water temperature, use the DHW push buttons (Part. 1 and 2 – fig. 1). It can be
varied from a minimum of 40°C to a maximum of 55°C.
Room temperature adjustment (using a room thermostat )
Using the room thermostat, set the temperature desired. Controlled by the room thermostat, the boiler
lights and heats the system water to the system delivery setpoint temperature. The burner shuts down
when the desired temperature in the room is reached.
A room thermostat and programmer are a mandatory requirement (Building regulations Doc ‘L’
2002).
Room temperature adjustment (using an optional Remote Control)
Using the remote control, set the temperature desired. The flow temperature will be controlled by the
remote control. For settings and other informations, see the relative manual.
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fig. 9
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fig. 10

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FERSYSTEM TECH 31 C
Cod. 3540U320 - 09/2009 (Rev. 00)
Economy/Comfort selection
The unit is equipped with a special internal device that ensures a high hot-water delivery speed and
excellent user comfort. When comfort mode is active the water in the boiler is maintained at a pre-de-
termined temperature, which means that hot water is available at the boiler outlet as soon as a tap is
opened, ie with no waiting.
The user can turn the device off (ECO mode) by pressing (part.7 - fig.1). In ECO mode the display
shows the relevant symbol (part. 12 - fig. 1). To turn on COMFORT mode, press (part.7 - fig.1) again,
the ECO symbol will vanish from the display.
Outside temperature compensation
When the (optional) external sensor kit is fitted to the appliance, the system can work in Outside tem-
perature compensation mode. In O.T.C. mode the temperature of the heating system is controlled
according to the external climate conditions, this will guarantee a high degree of comfort and energy
saving all year round.
By the CH push buttons (Part. 3 and 4 – fig. 1) is possible to set the maximum flow temperature
for the installation.
O.T.C. setting
To enter the OTC mode, press
reset
(Part. 6 – fig. 1) for 5 seconds.
The display shows CU flashing (fig. 11); to set Curve, use the DHW push buttons (Part. 1 and 2 – fig.
1). It can be varied from 1 to 10, in accordance with the chart (fig. 13). O means no O.T.C. mode.
It is recommended a start point of 20 - 30°C and a flow temperature of 85°C is required for the UK
(Curve 9 or 10).
By pressing the CH push buttons (Part. 3 e 4 – fig. 1), the display shows OF flashing (fig. 12); to
set Offset, use the DHW push buttons (Part. 1 and 2 – fig. 1). It can be varied from 20 to 40, in
accordance with the chart (fig. 14).
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fig. 11
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fig. 12

FERSYSTEM TECH 31 C
10 Cod. 3540U320 - 09/2009 (Rev. 00)
To exit the OTC mode, press
reset
(Part. 6 – fig. 1) for 5 seconds.
fig. 13
fig. 14
Maximum boiler flow temperature
Outside temperature
Outside temperature Outside temperature
Maximum boiler flow temperature
Maximum boiler flow temperature

1.5 Maintenance
It is strongly recommended to carry out annual maintenance of the boiler and heating system. Please
refer to the “maintenance” section in this manual.
The casing, the control panel and the aesthetic parts of the boiler can be cleaned using a soft and damp
cloth, do not use abrasives or solvents.
1.6 Faults
In the unlikely event of an operating problem, or component failure, the display flashes and a fault
identification code appears.
11
FERSYSTEM TECH 31 C
Cod. 3540U320 - 09/2009 (Rev. 00)
The boiler is equipped with an advanced self-diagnosis system that signals any faults on the display.
Some faults (“A“ indication) cause a boiler shutdown. In this case, operation must be reset manually by
pressing the
reset
(Part. 6 – fig. 1) for 1 second.
Other faults (“F“ indication) cause temporary shutdowns that are automatically reset as soon as the
value causing the fault comes back within the boiler’s normal working range.
Listed below are some anomalies that can be caused by simple, user-solvable problems.
If the problem remains after two attempts at resetting, contact the Fer Service Centre.
For other faults, refer to section 3.4 “Troubleshooting”.
Fault Cure
No burner ignition
Make sure that the gas cocks ahead of the boiler
and on the meter are open.
Press the RESET button (for 1 second).
In case of repeated shutdowns, contact the Fer
Service centre.
Low system pressure Fill the ‘system to 1-1.5 bar.
Before calling a Fer service engineer, check that the problem is not due to there being no gas
or electricity, or low system pressure.

FERSYSTEM TECH 31 C
12 Cod. 3540U320 - 09/2009 (Rev. 00)
2. INSTALLATION
2.1 General Instructions
This device must only be used for the purpose for which it is specially designed. This unit is
designed to heat water to a temperature below boiling point and must be connected to a hea-
ting system and/or a water supply system for domestic use, compatible with its performance,
characteristics and its heating capacity. Any other use is considered improper.
BOILER INSTALLATION MUST ONLY BE PERFORMED BY QUALIFIED PERSONNEL, IN ACCORDANCE
WITH ALL THE INSTRUCTIONS GIVEN IN THIS TECHNICAL MANUAL, THE PROVISIONS OF CURRENT
LAW, THE RECOMENDATION OF BS STANDARDS, ANY LOCAL REGULATIONS AND THE RULES OF
COMPETENT WORKMANSHIP.
Incorrect installation can cause damage or physical injury for which the manufacturer declines any
responsibility.
This appliance must be installed strictly in accordance with these instructions and
regulations:
The Gas Safety Regulations (Installations & Use).
The Local Building Regulations.
The Building Regulations (Part L).
The Buildings Standards (Scotland - Consolidated) Regulations.
British Standards Codes of Practice:
B.S. 5440 Part 1 Flues
B.S. 5440 Part 2 Air supply
B.S. 5449 FORCED CIRCULATION HOT WATER SYSTEMS
B.S. 6798 INSTALLATION OF GAS FIRED HOT WATER BOILERS
B.S. 6891 GAS INSTALLATIONS
B.S. 7671 IEE WIRING REGULATIONS
B.S. 4814 SPECIFICATION FOR EXPANSION VESSELS
B.S. 5482 INSTALLATION OF LPG
B.S. 7593 TREATMENT OF WATER IN DOMESTIC HOT WATER CENTRAL HEATING SYSTEMS
B.S. 5546 INSTALLATION OF HOT WATER SUPPLIES FOR DOMESTIC PURPOSES
Model Water Bye Laws
B.S. 5955-8 PLASTIC PIPEWORK INSTALLATION
For Northern Ireland the rules in force apply

13
FERSYSTEM TECH 31 C
Cod. 3540U320 - 09/2009 (Rev. 00)
Minimum
A
B
D
2,5 cm
20 cm
60 cm
(via an openable panel)
C30 cm
Table 1
fig. 15
A A
B
D
C
2.2 Boiler location
The unit’s combustion circuit is sealed off from
the installation room and therefore requires no
compartment ventilation.
The installation room must be sufficiently well
ventilated to prevent any dangerous condi-
tions from forming in the event of even slight
gas leakage. This safety standard is required
by the EEC Directive no. 90/396 for all gas
units, including those with a so-called sealed
chamber.
Therefore the place of installation must be
free of dust, flammable materials or objects
or corrosive gases. The room must be dry and
not subject to freezing.
The boiler is designed to be installed on a solid
wall. The wall fixing must ensure a stable and
effective support for the appliance, using the
bracket and fixings supplied.
If the unit is enclosed in a cupboard or moun-
ted alongside, there must be space for normal
maintenance work. Fig. 15 and tab. 1 gives the
minimum clearances to leave around the unit.
Safe Handling of Substances
Care should be taken when handling the boiler
insulation panels, which can cause irritation to the skin. No asbestos, mercury or CFCs are included in
any part of the boiler.
Product Handling Advise
When handling or lifting always use safe techniques - keep your back straight, bend your knees, don’t
twist - move your feet, avoid bending forwards and sideways and keep the load as close to your body
as possible.
Where possible transport the boiler using a sack truck or other suitable trolley.
Always grip the boiler firmly, and before lifting feel where the weight is concentrated to establish the
centre of gravity, repositioning yourself as necessary.

FERSYSTEM TECH 31 C
14 Cod. 3540U320 - 09/2009 (Rev. 00)
fig. 16
1 2 3 5
7 6
4
83 76 54 51 80 56
179,2
231,2
2.3 Boiler water connections
The heating capacity of the unit should be previously established by calculating the building’s heat requi-
rement according to current regulations. For good operation and long life of the boiler, the plumbing
system must be well proportioned and always complete with all those accessories that guarantee regular
operation and running, room thermostat, trv’s etc. The flow and return must be a minimum diameter of
22 mm for the first 3 metres from the appliance.
If the flow and return pipes follow a path where air pockets could form in certain places, it is essential to
install vent valves at these points. Also, install type “A” drain cocks at the lowest points in the system
to allow complete draining.
The temperature differential between the flow manifold and the return to the boiler should not exceed
20° C.
A minimum flow of 6 litres/min is required through the heat exchanger. An automatic by-pass is fitted
to the boiler which will provide this flow rate in most circu-
mstances.
Do not use the water system pipes to earth electrical
appliances.
Before installation, carefully flush all the pipes of the heating
system to remove residues or impurities that could affect the
unit’s operation (BS 7593 Building regs Doc L).
Make the connections to the appliance as shown in fig. 16
Key
1 System flow (22 mm with isolation valve fitted)
2 DHW outlet (15 mm )
3 Gas inlet (22 mm with isolation valve fitted)
4 Cold main inlet (15 mm with isolation valve fitted)
5 System return - 22 mm with isolation valve fitted (c/w filter)
6 Pressure Relief Valve
7 Condense outlet
It is essential to install the isolation valves supplied between the boiler and heating system, allowing the
boiler to be isolated from the system if necessary.
The safety valve outlet must be connected to a 15mm diameter copper pipe, with a continual
fall from the boiler to allow system water out onto the ground in the event of over-pressure in
the heating circuit. If this is not done, and the drain valve trips and floods the room, the boiler
manufacturer is not to be held responsible. The outlet should face back against the outer bri-
ckwork or building face to prevent harm or injury from hot water discharging in the event of an
over-pressurised system.
Make the boiler connection in such a way that its internal pipes are free of stress. If a check valve is
installed on the tap water circuit (where applicable), it is necessary to mount a safety valve between the
boiler and this circuit (check valve minimum 3 metres from boiler) or a domestic expansion vessel.

15
FERSYSTEM TECH 31 C
Cod. 3540U320 - 09/2009 (Rev. 00)
fig. 17
The isolation valves and filling kit shown in Fig. 17 is supplied as standard.
Make Up Water
Provision must be made for replacing water lost from the sealed system. Reference should be made
to BS6798, for methods of filling and making up sealed systems. There must be no direct connection
between the boiler's central heating system and the mains water supply. The use of mains water to
charge and pressurise the system directly, is conditional upon the Local Water Byelaws. Again any such
connection must be disconnected after use.
A filling connection is supplied with the valve set in the boiler box.
Attention - is drawn to the Model Water Byelaws.
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Key
A Cold water inlet valve
B Double check valve
C Blanking cap
D Removable connection
E Blanking plug
FIsolation valve
G C/H return valve & filter
fig. 18 fig. 19
1- The kit consist of the following items shown in fig 17.
2- Connect the items together as shown in fig. 18. 3- .....and then connect the completed assembly
to the boiler as shown in fig. 19.

FERSYSTEM TECH 31 C
16 Cod. 3540U320 - 09/2009 (Rev. 00)
Water treatment
If treatment is used fer limited recommanded only the use of Fernox or Sentinel water treatment pro-
ducts, which must be used in accordance with the manufacturers instructions. for further information
contact:
Fernox Manufacturing Co. LTD. Sentinel Performance Solutions Ltd
Cookson Electronics, Forsyth Road The Heath Business & Technical Park
Sheerwater, Woking, surrey, GU21 5RZ Runcorn, Cheshire WA7 4QX
Tel: [phone] Tel: [phone]
Note - If the boiler is installed in an existing system any unsuitable additives must be removed by tho-
rough cleansing. All systems should be cleansed according to B.S. 7593.
Note - In hard water areas treatment to prevent lime scale may be necessary.
Note - It is important that the correct concentration of the water treatment product is maintained in
accordance with the manufacturers instructions.
2.4 Connection to the gas system
If necessary the local Gas supplier should be consulted, at the installation planning stage, in order to
establish the availability of an adequate supply of gas.
An existing service pipe must not be used without prior consultation with the local Gas supplier.
A gas meter can only be connected by the Local Gas supplier, or by a Local Gas suppliers Contractor.
Installation pipes should be fitted in accordance with BS6891.
Appliance inlet working pressure must be 20mbar MINIMUM, for NG and 37 mbar minimum for LPG.
Do not use pipes of a smaller size than the combination boiler inlet gas connection (22 mm).
The complete installation must be tested for gas soundness and purged as described in BS689. All
pipework must be adquately supported. An isolating gas valve is provided and should be fitted on
the boiler gas inlet. Please wait 10 minutes when lighting from cold before checking. Gas pressures
should be checked after the boiler has operated for 10 minutes to reach thermal equilibrium. This
appliance has no facility to check the burner pressure, however if the inlet pressure and the gas
rate are correct the boiler should be set correctly, the gas valve is set and sealed at the factory
and should not be adjusted without authorisation from Fer Personnel. A combustion test can be
carried out to ensure correct air/gas mix (see page 28 combustion analyser testing).
The isolation kit shown in Fig. 17 is supplied as standard.
2.5 Electrical Connections
The unit must be installed in conformity with current national and local regulations.
Connection to the electrical supply
The boiler must be connected to a single-phase, 230 Volt-50 Hz electric supply.
The unit’s electrical safety is only guaranteed when correctly connected to an efficient earthing
system installed according to current safety standards. Have the efficiency and suitability of the
earthing system checked by professionally qualified personnel. The manufacturer is not responsible
for any damage caused by failure to earth the system. Also make sure that the electrical system
is adequate for the maximum power absorbed by the unit, as specified on the boiler dataplate,
in particular ensuring that the cross sectional area of the system’s cables is suitable for the power
absorbed by the unit.
The boiler is prewired and provided with a cable and fitted with a 3 amp fused plug for connection to
the electricity supply. It is important to respect the polarities (LIVE: brown wire / NEUTRAL: blue wire
/ EARTH: yellow-green wire) in making connections to the electrical supply.

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FERSYSTEM TECH 31 C
Cod. 3540U320 - 09/2009 (Rev. 00)
fig. 20
The user must never change the unit’s power cable. If the cable gets damaged, switch off the unit
and have it changed only by professionally qualified personnel. If changing the electric power cable,
use only “HAR H05 VV-F” 3x0.75 mm2cable with a maximum outside diameter of 8 mm.
Access to the electrical terminal block
Follow the instructions given in fig. 20 to access the electrical connection terminal board. The layout of
the terminals for the various connections is given in the wiring diagram in the Technical Data chapter.
Key
72 Room thermostat (Volt Free)
138 Outside temperature sensor
139 Room unit (OpenTherm) fig. 21

FERSYSTEM TECH 31 C
18 Cod. 3540U320 - 09/2009 (Rev. 00)
2.6 Flue system
The unit is “type C” with a sealed chamber and forced draught, the air inlet and flue outlet must be
connected to one of the following flue systems. With the aid of the tables and methods of calculation indi-
cated, before commencing installation, it is first necessary to check that the flue system does not exceed
the maximum permissible length. The current standards and local regulations must be observed.
It should be noted that only Fer flue system and accessories should be used on this appliance,
as per BS 5440 2000 and C.E. test certification.
Room thermostat
CAUTION: THE ROOM THERMOSTAT MUST HAVE VOLTAGE FREE CONTACTS. CONNECTING
230 V. TO THE TERMINALS OF THE TIME CLOCK AND ROOM THERMOSTAT WILL IRREPARA-
BLY DAMAGE THE P.C.B.

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FERSYSTEM TECH 31 C
Cod. 3540U320 - 09/2009 (Rev. 00)
Connection with coaxial pipes
fig. 22 - Examples of connection with coaxial pipes ( = Air / = Fumes)
For coaxial connection, fit the unit with one of the following starting accessories. For the wall hole dimensions, refer to
sec. 4.1. Any horizontal sections of the fume exhaust must be kept sloping slightly towards the boiler, to prevent pos-
sible condensate from flowing back towards the outside and causing dripping.
Starting accessory for coaxial ducts
Before proceeding with installation, check with table 2 that the maximum permissible length is not exceeded, bearing
in mind that every coaxial bend gives rise to the reduction indicated in the table. For example, a Ø 60/100 duct compris-
ing a 90° bend + 1 horizontal metre has a total equivalent length of 2 metres.
Table. 2 - Max. length coaxial ducts
Coaxial 60/100 Coaxial 80/125
Max. permissible length 5 m 15 m
Reduction factor 90° bend 1 m 0.5 m
Reduction factor 45° bend 0.5 m 0.25 m
C
13
C
13
C
33
C
33
C
33
C
13
Ø 100
Ø 60
120
142
Ø 80
Ø 127
120
147
Ø 100
Ø 60
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FERSYSTEM TECH 31 C
20 Cod. 3540U320 - 09/2009 (Rev. 00)
Connection with separate pipes
fig. 24 - Examples of connection with separate pipes ( = Air / = Fumes)
For connection of the separate ducts, fit the unit with the following starting accessory:
C 53
C 33 C
53
B 23 C 13
Starting accessory for separate ducts
Before proceeding with installation make sure the maximum permissible length has not been exceeded, by means of a
simple calculation:
1. Establish the layout of the system of split flues, including accessories and outlet terminals.
2. Consult the table 4 and identify the losses in meq (equivalent metres) of every element, according to the installation
position.
3. Check that the sum total of losses is less than or equal to the maximum permissible length in table 3.
Table. 3 - Max. length separate ducts
Separate ducts
Max. permissible length 75 meq
Ø 81Ø 81
Ø 65
Ø 87
Ø 65
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