Ariston microGENUS II 31 MFFI User guide

microGENUS II 24 MFFI
microGENUS II 28 MFFI
microGENUS II 31 MFFI
Installation and Servicing
Instructions
Type C Boilers
G.C.N: 47-116-25 (24kW)
G.C.N: 47-116-26 (28kW)
G.C.N: 47-116-27 (31kW)
LEAVE THESE INSTRUCTIONS WITH
THE END-USER
Country of destination: GB, IE
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TABLE OF CONTENTS
1. GENERAL INFORMATION PAGE.3
1.1 GENERAL INSTRUCTIONS PAGE.3
1.2 OVERALL VIEW PAGE.4
2. INSTALLATION PAGE.4
2.1 REFERENCE STANDARDS PAGE.5
2.2 SITING THE APPLIANCE PAGE.5
2.3 OVERALL DIMENSIONS PAGE.6
2.4 CLEARANCES PAGE.6
2.5 MOUNTING THE APPLIANCE PAGE.6
2.6 ELECTRICAL CONNECTION PAGE.7
2.7 GAS CONNECTION PAGE.8
2.8 WATER CONNECTION PAGE.8
2.9 FLUE CONNECTION PAGE.10
2.10 CONTROL PANEL PAGE.18
2.11 DIGITAL DISPLAY AND FAULT CODES PAGE.18
2.12 REMOVING THE FRONT PANEL PAGE.19
2.13 ROOM THERMOSTAT
CONNECTION PAGE.19
2.14 ELECTRICAL/SYSTEM DIAGRAMS PAGE.20
2.15 WATER CIRCUIT DIAGRAM PAGE.21
3. COMMISSIONING PAGE.22
3.1 INITIAL PREPARATION PAGE.22
3.2 INITIAL START-UP PAGE.23
3.3 OPERATIONAL ADJUSTMENTS PAGE.23
3.4 COMBUSTION ANALYSIS PAGE.24
3.5 PRODUCT OF COMBUSTION
DISCHARGE MONITORING PAGE.24
3.6 BOILER SAFETY SYSTEMS PAGE.24
3.7 DRAINING THE SYSTEM PAGE.26
3.8 COMPLETION PAGE.26
3.9 OPERATIONAL CHECKS PAGE.26
3.10 INSTRUCTING THE END USER PAGE.26
4. GAS ADJUSTMENTS PAGE.27
4.1 CHANGING THE TYPE OF GAS PAGE.27
4.2 ADJUSTING THE GAS PRESSURES PAGE.28
5. MAINTENANCE PAGE.32
6. SERVICING INSTRUCTIONS PAGE.33
6.1 REPLACEMENT OF PARTS PAGE.33
6.2 TOGAIN GENERAL ACCESS PAGE.33
6.2.1 REMOVING THE FRONT
PANEL PAGE.33
6.2.2 REMOVING THE SEALED
CHAMBER FRONT PANEL PAGE.34
6.2.3 REMOVING THE SIDE
PANELS PAGE.34
6.3 ACCESS TO THE COMBUSTION
CHAMBER PAGE.35
6.3.1 REMOVING THE
COMBUSTION CHAMBER PAGE.35
6.3.2 REMOVING THE BURNER
AND JETS PAGE.35
6.3.3 REMOVING THE
ELECTRODES PAGE.35
6.3.4 REMOVING THE MAIN HEAT
EXCHANGER PAGE.36
6.3.5 REMOVING THE AIR
PRESSURE SWITCH PAGE.37
6.3.6 REMOVING THE FAN PAGE.38
6.4 ACCESS TO THE GAS VALVE PAGE.38
6.4.1 REMOVING THE SPARK
GENERATOR PAGE.38
6.4.2 REMOVING THE GAS VALVE PAGE.39
6.5 ACCESS TO THE WATER CIRCUIT PAGE.39
6.5.1 REMOVING THE D.H.W. (SECONDARY)
EXCHANGER PAGE.39
6.5.2 REMOVING THE PUMP
PRESSURE SWITCH PAGE.40
6.5.3 REMOVING THE SAFETY
VALVE PAGE.41
6.5.4 REMOVING THE AUTOMATIC
AIR VENT PAGE.41
6.5.5 REMOVING THE PUMP PAGE.42
6.5.6 REMOVING THE PRESSURE
GAUGE PAGE.43
6.5.7 REMOVING THE EXPANSION
VESSEL PAGE.43
6.5.8 REMOVING THE OVERHEAT
THERMOSTAT PAGE.44
6.5.9 REMOVING THE C.H.
TEMPERATURE PROBE (N.T.C.) PAGE.44
6.5.10 REMOVING THE D.H.W.
TEMPERATURE SENSOR
(N.T.C.) PAGE.45
6.5.11 REMOVING THE DIVERTOR
VALVE ACTUATOR PAGE.45
6.5.12 REMOVING THE D.H.W.
FLOWSWITCH PAGE.45
6.6 ACCESS TOTHE CONTROL SYSTEM PAGE.46
6.6.1 CHECKING THE FUSES PAGE.46
6.6.2 REMOVING THE P
.C.B. PAGE.47
6.6.3 REMOVING THE TIME CLOCK PAGE.48
7. FAULT FINDING PAGE.49
7.1 FAULTFINDING GUIDE
(FLOW-CHARTS)PAGE.49
8. EXPLODED VIEW PAGE.52
8.1 SHORT SPARES LIST PAGE.53
9. TECHNICAL INFORMATION PAGE.54

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This manual is an integral and essential part of the
product. It should be kept with the appliance so that it can
be consulted by the user and our authorised personnel.
Please carefully read the instructions and notices about
the unit contained in this manual, as they provide
important information regarding the safe installation, use
and maintenance of the product.
For operating instructions please consult the separate
Users Manual.
1. GENERAL INFORMATION
1.1 GENERAL INSTRUCTIONS
Read the instructions and recommendations in these
Installation and Servicing Instructions carefully to ensure
proper installation, use and maintenance of the
appliance.
Keep this manual in a safe place. You may need it for your
own reference while Servicing Technicians or your
installer may need to consult it in the future.
This is a combined appliance for the production of central
heating (C.H.) and domestic hot water (D.H.W.) and is
intended for use in domestic properties.
This appliance must be used only for the purpose for
which it is designed.
The manufacturer declines all liability for damage caused
by improper or negligent use.
No asbestos or other hazardous materials have been
used in the fabrication of this product.
Before connecting the appliance, check that the
information shown on the data plate and the table in
section 9 comply with the electric, water and gas mains of
the property. You will find the data plate on the reverse of
the control panel.
The gas with which this appliance operates is also shown
on the data label inside the boiler casing.
Do not install this appliance in a damp environment or
close to equipment which spray water or other liquids.
Do not place objects on the appliance.
Do not allowchildren or inexperienced persons to use
the appliance without supervision.
If you smell gas in the room, do not turn on or off light
switches, use the telephone or any other object which
might cause sparks.
Open doors and windows immediately to ventilate the
room.
Shut the gas mains tap (at or adjacent to the gas meter)
or the valve of the gas cylinder and call your Gas Supplier
immediately.
If you are going away for a long period of time, remember
to shut the mains gas tap or the gas cylinder valve.
Always disconnect the appliance either by unplugging it
from the mains or turning off the mains switch before
cleaning the appliance or carrying out maintenance.
In the case of faults or failure, switch off the appliance
and turn off the gas tap. Do not tamper with the
appliance.
For repairs, call your local Authorised Servicing Agent
and request the use of original spare parts. For in-
guarantee repairs contact MTS (GB) Limited.

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LEGEND:
1. Flue Manifold
2. Air Intake for Twin Pipe Flue Systems
3. Fan
4. Combustion Chamber Hood
5. Main Heat Exchanger
6. Overheat Thermostat
7. Central Heating Flow Temperature Probe
8. Combustion Chamber Insulation Panel
9. Burner
10. Detection Electrode
11. Ignition Electrodes
12. Motorised Valve
13. Domestic Hot Water Temperature Probe
14. Drain Valve
15. Low Water Pressure Switch
16. Secondary Heat Exchanger
17. Gas Valve
18. Spark Generator
19. Cold Water Inlet Filter
20. Pump (w/auto air vent)
21. Safety Valve
22. D.H.W.Flow Switch
23. Combustion Chamber
24. Central Heating Return Temperature Probe
25. Expansion Vessel
26. Air Pressure Switch
27. Combustion Analysis Test Point
1.2 OVERALL VIEW
FIG.1.0

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2.1 REFERENCE STANDARDS
2. INSTALLATION
The technical information and instructions provided
herein below are intended for the installer / Servicing
Technician so that the unit may be installed and serviced
correctly and safely.
The appliance is only suitable for installation in GB and IE
and should be installed in accordance with the rules in
force
In GB, the installation must be carried out by a CORGI
registered installer. It must be carried out in accordance
with the relevant requirements of the Gas Safety
(Installation and Use) Regulations, the appropriate
Building Regulations either The Building Regulations
(Scotland), Building Regulations (Northern Ireland), The
Water Fittings Regulations or Water byelaws in Scotland.
In GB, it is necessary to comply with the Water Supply
(Water Fittings) Regulations 1999 (or for Scotland, The
Water Byelaws 2000, Scotland).
The microGENUS II is an Approved Product under the
Water Regulations.
To comply with the Water Regulations your attention is
drawn to The Water Regulations guide, published by the
Water Regulations Advisory Service (WRAS) gives full
details of the requirements. In IE, the requirements given
in the current edition of I.S.813 and the current Building
Regulations must be followed.
Installation should also comply with the following British
Standard Codes of Practice
In the Republic of Ireland in accordance with the current
Building Regulations, the current ETCI rules for electrical
installation and with the following Codes of Practice:
BS 7593:1992 Treatment of water in domestic hot water
central heating systems
BS 5546:1990 Installation of hot water supplies for
domestic purposes
BS 5440-1:2000 Flues
BS 5440-2:2000 Air supply
BS 5449:1990 Forced circulation hot water systems
BS 6798:1987 Installation of gas fired hot water boilers
of rated input not exceeding 60kW
BS 6891:1989 Installation of low pressure gas pipe up to
28mm
BS 7671:2001 IEE wiring regulations
BS 4814:1990 Specification for expansion vessels
BS 5482:1994 Installation of L.P.G.
I.S. 813 Domestic Gas Installations
The appliance may be installed in any room or indoor
area, although particular attention is drawn to the
requirements of, in GB the current I.E.E. Wiring
Regulations, in Scotland, the electrical provisions of the
Building Regulations applicable in Scotland, and for IE
the current edition of I.S. 813 and the current ETCI rules.
With respect to the installation of the combined appliance
in a room containing a bath or shower, the location of the
boiler in a room containing a bath or shower should only
be considered if there is no alternative.
Where a room-sealed appliance is installed in a room
containing a bath or shower reference must be made
to the relevant requirements. In GB this is the current
I.E.E. Wiring Regulations and Building Regulations, in
IE reference should be made to the current edition of
I.S. 813 and the current ETCI rules.
If the boiler is to be fitted into a building of timber frame
construction, reference should be made to the current
edition of the Institution of Gas Engineers Publication
IGE/UP/7 (Gas Installations in Timber Framed Housing).
The location must permit adequate space for servicing
and air circulation around the appliance as indicated in
Section 2.4.
The location must permit the provision of an adequate
flue and termination.
For unusual locations special procedures may be
necessary.
BS 6798-1987 gives detailed guidance on this aspect.
A compartment used to enclose the appliance must be
designed specifically for this purpose. No specific
ventilation requirements are needed for the installation
within a cupboard.
This appliance is not suitable for outdoor installation.
The type C appliances (in which the combustion
circuit, air vent intake and combustion chamber are
air-tight with respect to the room in which the
appliance is installed) can be installed in any type of
room.
Secondary ventilation is not required with this boiler. The
boiler must be installed on a solid, non-combustible,
permanent wall to prevent access from the rear.
2.2 SITING THE APPLIANCE

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After removing the boiler from its packaging, remove the
template from the separate box containing the connection
kit. NOTE:Pay particular attention to any test water that
may spill from the appliance.
Place the template in the position the appliance is to be
mounted and after ensuring it is hanging squarely, use it
to drill the holes for the hanging bracket, connection kit
and flue pipe(s) NB: For further information relating to the
flue installation please refer to Section 2.9 FLUE
CONNECTION. (If the appliance is to be fitted on a wall of
combustible material, the wall must be protected by a
sheet of fireproof material).
If the appliance is to be fitted into a timber framed
building, guidance should be sought from the Institute of
Gas Engineers document REF: IGE/UP/7.
2.5.1. Drill the wall and plug using those supplied with
the connections kit, position the hanging bracket and
2.5 MOUNTING THE APPLIANCE
FIG. 2.2
In order to allow access to the interior of the boiler for
maintenance purposes, the boiler must be installed in
compliance with the minimum clearances indicated in FIG. 2.2
2.4 CLEARANCES
LEGEND:
A = Central Heating Flow (3/4”)
B = Domestic Hot Water Outlet (1/2”)
C = Gas Inlet (3/4”)
D = Domestic Cold Water Inlet (1/2”)
E = Central Heating Return (3/4”)
2.3 OVERALL DIMENSIONS
FIG. 2.1

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For safety purposes, have a competent person carefully
check the electrical system in the property, as the
manufacturer will not be held liable for damage caused by
the failure to earth the appliance properly or by anomalies
in the supply of power. Make sure that the residential
electrical system is adequate for the maximum power
absorbed by the unit, which is indicated on the rating
plate. In addition, check that the section of cabling is
appropriate for the power absorbed by the boiler.
The boiler operates with alternating current, as indicated
in the Technical Information table in Section 10, where the
maximum absorbed power is also indicated. Make sure
that the connections for the neutral and live wires
correspond to the indications in the diagram. The
appliance electrical connections are situated on the
reverse of the control panel.
IMPORTANT!
In the event that the power supply cord must be changed,
replace it with one with the same specifications.
Note: The diagrams for the electrical system are indicated
in section 2.13.
Warning, this appliance must be earthed.
External wiring to the appliance must be correctly earthed
and polarised and must be carried out by a competent
person in accordance with relevant regulations and rules,
in GB reference should be made to the current I.E.E.
Regulations and applicable local regulations, in Scotland,
the electrical provisions of the Building Regulations
applicable in Scotland, and for IE the current edition of
I.S. 813 and the current ETCI rules.
The appliance is supplied with a fly-lead already
connected, this must be connected to a 220-240v supply
fused at 3A and must facilitate complete electrical
isolation of the appliance, by the use of a fused double
pole isolator having a contact separation of at least 3 mm
in all poles or alternatively, by means of a 3 A fused
three pin plug and unswitched shuttered socket outlet
both complying with BS 1363.
The point of connection to the Electricity supply must be
readily accessible and adjacent to the appliance unless
the appliance is installed in a bathroom when this must
be sited outside the bathroom (see section 2.2).
Should external controls be required, the design of the
external electrical circuits should be undertaken by a
competent person, see Section 2.13 for further
information.
2.6 ELECTRICAL CONNECTION
FIG.2.3
secure with the wall screws supplied, assemble the
connection kit and secure to the wall. NOTE:It is highly
recommended that a spirit level be used to position the
appliance to ensure that it is perfectly level.
2.5.2. Position the appliance on the hanging bracket
and connect the connection kit to the boiler connections.
(see also Sections 2.7 Gas Connections, 2.8 Water
Connections & FIG. 2.3).

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VIEW OF THE BOILER CONNECTIONS
LEGEND:
A = Central Heating Flow
B = Domestic Hot Water Outlet
C = Gas Inlet
D = Domestic Cold Water Inlet
E = Central Heating Return
F= Safety Valve Outlet
G = Drain valve
2.8 WATER CONNECTIONS
2.7 GAS CONNECTION
The local gas region contractor connects the gas meter to
the service pipe.
If the gas supply for the boiler serves other appliances
ensure that an adequate supply is available both to the
boiler and the other appliances when they are in use at
the same time.
Pipe work must be of an adequate size. Pipes of a
smaller size than the boiler inlet connection should not be
used.
The gas installation should also be in accordance with the
relevant standards. In GB this is BS 6891, and in IE this
is the current edition of I.S. 813.
FIG.2.4
FIG.2.5 KT007A
CENTRAL HEATING
Detailed recommendations are given in BS 6798:1987
and BS 5449-1:1990, the following notes are given for
general guidance.
PIPE WORK:
Copper tubing to BS EN 1057:1996 is recommended for
water pipes.Jointing should be either with capillary
soldered or compression fittings.
Where possible pipes should have a gradient to ensure
air is carried naturally to air release points and water
flows naturally to drain taps.
The appliance has a built-in automatic air release valve,
however it should be ensured as far as possible that the
appliance heat exchanger is not a natural
collecting point for air.
Except where providing useful heat, pipes should be
insulated to prevent heat loss and avoid freezing.
Particular attention should be paid to pipes passing
through ventilated spaces in roofs and under floors.
BY-PASS:
The appliance includes an automatic by-pass valve,
which protects the main heat exchanger in case of
reduced or interrupted water circulation through the
heating system, due to the closing of thermostatic valves
or radiators. SYSTEM DESIGN:
This boiler is suitable only for sealed systems.
DRAIN COCKS:
These must be located in accessible positions to permit
the draining of the whole system and should be fitted at
all low points. The taps must be at least 15mm nominal
size and manufactured in accordance with BS 2870:1980.
SAFETY VALVE DISCHARGE:
ABCD
E
G
F
E

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The discharge should terminate facing downward on the
exterior of the building in a position where discharging
(possibly boiling water & steam) will not create danger or
nuisance, but in an easily visible position, and not cause
damage to electrical components and wiring.
The discharge must not be over an entrance or a window
or any other type of public access.
AIR RELEASE POINTS:
These must be fitted at all high points where air naturally
collects and must be sited to facilitate complete filling of
the system.
The appliance has an integral sealed expansion vessel to
accommodate the increase of water volume when the
system is heated.
It can accept up to 7 litres (1.3 gal) of expansion water. If
the heating circuit has an unusually high water content,
an additional sealed expansion vessel must be fitted, for
GB refer to BS 7074 part 1 and for IE, refer to the current
edition of I.S. 813.
MAINS WATER FEED - CENTRAL HEATING:
A method for initially filling the heating system is supplied
with the connection kit. The filling loop is connected
between the cold water inlet and the central heating flow
connections, and incorporates a non-return valve. To
operate the filling loop, it is necessary to open both
quarter turn handles, once the required pressure has
been achieved, close both handles and disconnect the
hose in accordance with water byelaws. NOTE: The
installer should ensure that there are no leaks as frequent
filling of the heating system can lead to premature scaling
of the main exchanger and failure of hydraulic
components.
DOMESTIC WATER:
The domestic water must be in accordance with the
relevant recommendation of BS 5546:1990. Copper
tubing to BS EN 1057:1996 is recommended for water
carrying pipe work and must be used for pipe work
carrying drinking water, a scale reducer should also be
used to reduce the risk of scale forming in the domestic
side of the heat exchanger.
VR003A
RESIDUAL PUMP HEAD,DESIGNED TEMP RISE 20oC
28/31 kW
24 kW

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NOTE:THE FLUE MUST NOT TERMINATE IN A PLACE LIKELY TO
CAUSE NUISANCE
2.9 FLUE CONNECTIONS
FLUE SYSTEM
The provision for satisfactory flue termination must be
made in GB this must be in accordance with BS 5440-1,
for IE recommendations are given in the current edition of
I.S.813.
The appliance must be installed so that the flue terminal is
exposed to outside air.
The terminal must not discharge into another room or
space such as an outhouse or lean-to.
It is important that the position of the terminal allows a
free passage of air across it at all times.
The terminal should be located with due regard for the
damage or discolouration that might occur on buildings in
the vicinity and consideration must be given to adjacent
boundaries.
In cold or humid weather water vapour may condense on
leaving the flue terminal. The effect of such “pluming”
must be considered.
If the terminal is less than 2 metres above a balcony,
above ground or above a flat roof to which people have
access, then a suitable terminal guard must be fitted.
When ordering a terminal guard, quote the appliance
model number.
A suitable terminal guard is available from:
TOWER FLUE COMPONENTS
Morley Road
Tonbridge
Kent TN9 1RA
The minimum acceptable spacing from the terminal to
obstructions and ventilation openings are specified in FIG.
2.6.
T ERMINAL P OSITION mm
A - Directly above or below an openable window
or other opening 300
B - Below gutters, solid pipes or drain pipes 75
C-Below eaves 200
D-Below balconies or car-port roof 200
E - From vertical drain pipes and soil pipes 150
F - From internal or external corners 300
G - Above ground or balcony level 300
H-From a surface facing a terminal 600
I - From a terminal facing a terminal 1200
J - From an opening in the car port
(e.g. door, window) into dwelling 1200
K-Vertically from a terminal in the same wall 1500
L - Horizontally from a terminal in the same wall 300
M-Horizontally from an opening window 300
N - Fixed by vertical flue terminal
FIG. 2.6 FU010D

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Ø 60/100 mm
FIG. 2.7 FU002A/Rev.1
FITTING THE COAXIAL FLUE (HORIZONTAL)
(For Telscopic, Vertical Flue and Twin Pipe Instructions
see page 12)
CONTENTS:
1XSILICONE O-RING (60mm)
1XELBOW (90O)
2XWALL SEALS (INTERNAL &EXTERNAL)
1XALUMINIUM FLUE PIPE INCLUDING TERMINAL (1 METRE -
60/100)
2XFLUE CLAMPS
8XSCREWS
2XFOAM SEALS
Once the boiler has been positioned on the wall, insert
the elbow into the socket (FIG 2.7) and rotate to the
required position. NOTE: It is possible to rotate the elbow
360oon its vertical axis.
Using the flue clamps, seals and screws supplied (FIGS
2.7 AND 2.9) secure the elbow to the boiler.
The 1 metre horizontal flue kit (705958) supplied is
suitable for an exact X dimension of 823mm, and the
750mm horizontal flue kit (705785) is suitable for an exact
X dimension of 573mm.
Measure the distance from the face of the external wall to
the face of the flue elbow (X - FIG 2.7), add 22 mm to this
measurement, you now have the total length of flue
required (including the terminal), this figure must now be
subtracted from 860mm, you now have the total amount
to be cut from the plain end of the flue.
Cut the flue to the required length ensuring that the
distance between the inner and the outer flue is
maintained (FIG 2.10).
FIG 2.8 FIG 2.9

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FIG 2.12
e.g. X = 508mm + 22mm = 530mm
860 - 530 = 330mm (Length to be cut from the plain
end of the flue).
Once cut to the required length, ensure that the flue is
free from burrs and reassemble the flue. If fitting the flue
from inside of the building attach the grey outer wall seal
to the flue terminal and push through the flue through the
hole, once the wall seal has passed through the hole, pull
the flue back until the seal is flush with the wall.
Alternatively, the flue can be installed from outside of the
building, the grey outer seal being fitted last.
FITTING THE TELESCOPIC FLUE KIT (HORIZONTAL)
CONTENTS:
1XSILICONE O-RING (60mm)
1XELBOW (90O)
2XWALL SEALS (INTERNAL &EXTERNAL)
1XALUMINIUM FLUE PIPE INCLUDING TERMINAL (TELESCOPIC -
60/100)
2XFLUE CLAMPS
8XSCREWS
2XFOAM SEALS
The telscopic flue is suitable for use with an exact
minimum Xdimension of 270mm and an exact maximum
X dimension 470mm.
IMPORTANT!!
Do not extend the telescopic flue to an X dimension
of more than 470mm. If longer lengths are required
use extension pieces as necessary. Under no
circumstances must the flue be cut.
The wall must then be made good around the flue
(ensuring a fall of 1ois maintained away from the boiler to
the flue terminal).
Once made good, place the inner (white) wall seal over
the flue and push up to the wall, secure the flue to the
elbow by using the clamp supplied.
For each additional 90oelbow 1 metre must be removed
from the total flue length (maximum 4 metres including
the 1st elbow). For each additional 45oelbow 0.5 metre
must be subtracted from the total flue length (FIG 2.13).
FITTING THE COAXIAL FLUE (VERTICAL)
(For Twin Pipe Instructions see page 13)
CONTENTS:
1XSILICONE O-RING (60mm)
1XELBOW (90O)
2XWALL SEALS (INTERNAL &EXTERNAL)
1XALUMINIUM FLUE PIPE INCLUDING TERMINAL (TELESCOPIC -
60/100)
2XFLUE CLAMPS
8XSCREWS
2XFOAM SEALS
The vertical flue kit is supplied with a specially designed
weather proof terminal fitted, it can be used either with a
flat roof or a pitched roof. (see FIGS 2.12, 2.13).
FIG 2.11
FIG 2.10
WARNING
IFTHE FLUE IS LONGER THAN 1 METRE,REMOVE THE
RESTRICTOR (FIG. 2.11). IF THE FLUE IS BETWEEN 0-1
METRE THE RESTRICTOR REMAINS FITTED.
SEE TABLE 2.1 (PAGE 17).

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NOTE:MAX LENGTH = a+a+a +
b+b = a+a+a+0.5+0.5
COMBINED LENGTH NOT
TO EXCEED 5m
FIG 2.13
FIG 2.14
The Vertical flue kits maximum and minimum useable
lengths with both flat and pitched roof flashings are
indicated in (Figs. 2.14 & 2.15).
Before proceeding to fit the flue, ensure that the
maximum flue length has not been exceeded and that all
elbows and bends have been taken into consideration,
the maximum flue length is 5 metres, for each additional
90oelbow 1 metre must be subtracted from the total flue
length, and for each 45o0.5 metres must be subtracted
from the total flue length (the offset and height of 2 x
45ocan be seen in Fig. 2.16).
Mark the position of the flue hole in the ceiling and/or roof
(see FIG. 2.14 for distance from wall to the centre of
the flue).
Cut a 125mm diameter hole through the ceiling and/or
roof and fit the flashing plate to the roof.
Should it be necessary to cut the flue DO NOTcut the
outer white air inlet tube, cut the aluminium exhaust flue
6mm longer than the outer white air tube when used at
minimum length. DO NOTcut more that 250mm from the
inner aluminium exhaust flue.
To connect the vertical flue kit directly to the boiler, place
the adaptor (see FIG 2.12) (supplied with vertical flue kit)
onto the exhaust manifold and secure with the clamp, the
vertical flue kit must then be inserted through the roof
flashing, this will ensure that the correct clearance above
the roof is provided as the terminal is a fixed height.
Should extensions be required, they are available in 1
metre (Part No. 705786), 500mm (Part No. 705790) and
160mm lengths (Part No. 705812), they must be
connected directly to the boiler and secured with the
clamp supplied before connecting the adaptor to allow the
vertical flue kit to be fitted. In the event that extension
pieces need to be shortened, they must only be cut at
the male end and it must be ensured that the distance
between the inner and outer flue are kept (Fig. 2.10).
When utilising the vertical flue system, action must be
taken to ensure that the flue is supported adequately to
prevent the weight being transferred to the appliance flue
connection.
When the flue passes through a ceiling or wooden floor,
there must be an air gap of 25mm between any part of
the flue system and any combustible material. The use of
a ceiling plate will facilitate this. Also when the flue
passes from one room to another a fire stop must be
fitted to prevent the passage of smoke or fire, irrespective
of the structural material through which the flue passes.
FITTING THE FLUE (TWIN PIPE)
Where it is not possible to terminate the flue within the
distance permitted for coaxial flues, the twin flue pipe can
be used by fitting a special adaptor to the flue connector
and using the aperture for the air intake located on top of
the combustion chamber.

14
Considerations necessary for twin flue installation;
It is most important to avoid any possible condense
formation entering the appliance.
According to Table 2.1 (Page 17) decide if condensation
will form within the flue. If yes, there are two options;
1) Where condense will form but can be negated with
insulated flue, install insulated the flue with a fall of
5mm in every metre away from the boiler.
2) The exhaust flue will have a fall of 3oback to the boiler
and a suitable trap will be fitted on the exhaust as
close to the boiler as possible, condense will then be
suitably disposed of.
Where the flue runs through cold spots, i.e. loft areas,
condense is likely to be formed, therefore a fall back to
the boiler and a trap is required.
Always ensure that the flue is adequately supported,
avoiding low points. (MTS supply suitable clamps as Part
No. 705778).
To utilise the air intake it is necessary to:
Remove the ‘knockout’ of the air intake by cutting it with a
suitable knife (FIG. 2.17).
Insert the elbow/flue pipe into the air intake until it stops.
The twin flue pipes can be fitted with or without additional
elbows and need no clamps, simply ensure that the red o-
ring is inserted in the female end of the flue pipe and
push the extension piece fully into the previous section of
flue pipe or elbow, check that the o-ring is not dislodged
when assembling the flue.
Twin pipe can also be converted back to Coaxial flue to
enable vertical termination with a coaxial kit by using the
pipe bridge (Twin - Coaxial Adaptor - Part No. 705767).
When running the twin flue pipe vertically, a condense
trap must always be used on the exhaust pipe.
It is not recommended that the pipe bridge for horizontal
termination, however in the unlikely event that this proves
to be a necessity it is extremely important that the entire
flue has a fall of 3oback to the boiler, is suitably trapped
and where the 60mm inner flue of the concentric terminal
connects to the pipe bridge, this point must be adequately
sealed with silicone sealant to avoid condense leakage at
this point.
NOTE:Vertical twin flue installations must have a trap on
the exhaust. MTS supply a suitable condense
trap Part No. 705774 and recommend that this be
used in the event that the flue may not form
condense.
When siting the twin flue pipe, the air intake and exhaust
terminals must terminate on the same wall, the centres of
the terminal centres must be a minimum of 280 mm apart
FIG 2.15
FIG 2.16
Minimum offset distance when using 2x 45obends
WARNING
IF THE FLUE IS LONGER THAN 1 METRE,REMOVE THE
RESTRICTOR (FIG.2.11). IFTHE FLUE IS BETWEEN 0-1
METRE THE RESTRICTOR REMAINS FITTED.
SEE TABLE 2.1 (PAGE 17).

15
FIG 2.18
IMPORTANT!!!
WHERE CONDENSE WILL FORM WITHIN THE FLUE SYSTEM,
ENSURE THERE IS A FALL BACK TO THE BOILER OF 3OAND A
SUITABLE TRAP IS FITTED AS CLOSE TO THE BOILER AS
POSSIBLE. MTS SUPPLY A SUITABLE COLLECTOR PART NO.
705798 OR A CONDENSATE DISCHARGE T WITH BUILT IN TRAP
PART NO. 705774.
FIG 2.17
FIG 2.19
and the air intake must not be sited above the exhaust
terminal (refer to FIG.2.21).The air intake pipe can be
run horizontally, however, the terminal and the final 1
metre of flue must be installed with a fall away from the
boiler to avoid rain ingress.
It is also strongly recommended that the air intake pipe
run be constructed of insulated pipe to prevent condense
forming on the outside of the tube.
The maximum permissible flue length for twin flue is
dependent on the type of run used.
For flue runs with the intake and exhaust pipes under the
same atmospheric conditions (TYPE 4) the maximum
length is 60 metres (28kW), 46 metres (28kW) and 47
metres (31kW). For runs with the terminals under
different atmospheric conditions (TYPE 5) the exhaust
terminal must extend 0.5 metres above the ridge of the
roof (this is not obligatory if the exhaust and air intake
pipes are located on the same side of the building). For
TYPE 5 also, the maximum permissible combined length is
59 metres (24kW), 48 metres (28kW) and 42 metres
(31kW). Flue types are shown on Page 16 (FIG. 2.20).
The maximum length is reached by combining the total
lengths of both the air intake and exhaust pipes.
Therefore a maximum length of 40 metres for example,
will allow a flue run of 20 metres for the air intake and 20
metres for the exhaust pipes, also for each 90oelbow 1.3
metres must be subtracted from the total length and for
each 45oelbow 1 metre must be subtracted from the total
flue length.
Some of the acceptable flue configurations are detailed
on page 16 (FIG.2.20).
For further information relating to flue runs not illustrated,
please contact the Technical Department on 01494
539579.

16
EXHAUST
AIR INTAKE
AIR INTAKE
AIR INTAKE MUST NOT BE
FITTED ABOVE THE EXHAUST
FIG 2.21
NOTE: DRAWINGS ARE INDICATIVE OF FLUEING OPTIONS ONLY.
FIG.2.20
TYPE 1
TYPE 5
TYPE 4
TYPE 3
TYPE 2
NOTE:WHERE 280MM CENTRES CANNOT BE ACHEIVED,THE EXHAUST TERMINAL
CAN BE EXTENDED TO PROTRUDE FROM THE WALL BY 300MM.

17
TABLE 2.1
Exhaust
Type
TYPE 4
TYPE 5
Use the
ø 42 mm
Restrictor
Between
1m - 4 m
Between
1m - 11.5 m
Maximum
Flue
Length
47 m
42 m
Risk of Condensation Forming With:
Twin Pipe
Systems
ø 80/80
2 m
with a
ø 42 mm
restrictor
7.4 m
with a
ø 42 mm
restrictor
2 m
with a
ø 42 mm
restrictor
7.4 m
with a
ø 42 mm
restrictor
Exhaust
Type
TYPE 1
TYPE 2
TYPE 3
Use the
ø 42 mm
Restrictor
Between
500 mm - 1 m
Maximum
Flue
Length
4 m
5 m
Do not use the
Restrictor
Between 1m - 4m
Between 1m - 5m
Risk of Condensation Forming
Coaxial
Systems
ø 60/100
NOT APPLICABLE NOT APPLICABLE
Standard Twin Pipe
After:
7.5 m
without a
ø 42 mm
restrictor
7.4 m
without a
ø 42 mm
restrictor
7,5 m
without a
ø 42 mm
restrictor
7,4 m
without a
ø 42 mm
restrictor
Insulated Twin Pipe
After:
Do not use the
Restrictor
Between
4 m - 47 m
Between
11.5 m - 42 m
Exhaust
Type
TYPE 4
TYPE 5
Use the
ø 43 mm
Restrictor
Between
1m - 14 m
Between
1m - 21 m
Maximum
Flue
Length
46 m
48 m
Risk of Condensation Forming With:
Twin Pipe
Systems
ø 80/80
4 m
with a
ø 43 mm
restrictor
4 m
with a
ø 43 mm
restrictor
4 m
with a
ø 43 mm
restrictor
4 m
with a
ø 43 mm
restrictor
Exhaust
Type
TYPE 1
TYPE 2
TYPE 3
Use the
ø 43 mm
Restrictor
Between
500 mm - 1 m
Maximum
Flue
Length
4 m
5 m
Do not use the
Restrictor
Between 1m - 4m
Between 1m - 5m
Risk of Condensation Forming
Coaxial
Systems
ø 60/100
NOT APPLICABLE NOT APPLICABLE
Standard Twin Pipe
After:
5 m
without a
ø 43 mm
restrictor
5 m
without a
ø 43 mm
restrictor
5 m
without a
ø 43 mm
restrictor
5 m
without a
ø 43 mm
restrictor
Insulated Twin Pipe
After:
Do not use the
Restrictor
Between
14 m - 46 m
Between
21 m - 48 m
Exhaust
Type
TYPE 4
TYPE 5
Use the
ø 41 mm
Restrictor
Between
1m - 20 m
Between
1m - 25 m
Maximum
Flue
Length
60 m
59 m
Risk of Condensation Forming With:
Twin Pipe
Systems
ø 80/80
3 m
with a
ø 41 mm
restrictor
3 m
with a
ø 41 mm
restrictor
3 m
with a
ø 41 mm
restrictor
3 m
with a
ø 41 mm
restrictor
Exhaust
Type
TYPE 1
TYPE 2
TYPE 3
Use the
ø 41 mm
Restrictor
Between
500 mm - 1 m
Maximum
Flue
Length
4 m
5 m
Do not use the
Restrictor
Between 1m - 4m
Between 1m - 5m
Risk of Condensation Forming
Coaxial
Systems
ø 60/100
NOT APPLICABLE NOT APPLICABLE
Standard Twin Pipe
After:
4 m
without a
ø 41 mm
restrictor
4 m
without a
ø 41 mm
restrictor
4 m
without a
ø 41 mm
restrictor
4 m
without a
ø 41 mm
restrictor
Insulated Twin Pipe
After:
Do not use the
Restrictor
Between
20 m - 60 m
Between
25 m - 59 m
*Where there is no risk of condense forming (and,
therefore no requirement for a condense collector),
ensure a minimum fall of 5mm per metre away from
the appliance.
NOTE:UNDER SOME CIRCUMSTANCES,CONDENSE MAY FORM AT
THE EXHAUST TERMINAL,SPECIAL ATTENTION MUST BE
PAID WITH REGARD TO POSSIBLE CONDENSE DRIPPING
FROM THE TERMINAL.
24 MFFI
28 MFFI
31 MFFI

18
1
2
3
4
5
6
1
2
3
4
5
6
EC
II
IJK
LEGEND:
A-On/Off Button
B- Domestic Hot Water Temperature Adjustment
C- Central Heating Temperature Adjustment
D- Reset Button/Flue Test analysis mode*
E- Comfort Mode Selector
F- Summer Mode LED (Green)
G-Ignition/Overheat Lockout LED (Red)
H- Central Heating (Winter Mode) LED (Green)
I- Digital Display (Fault Code/Water Temperature)
J- Time Clock
K- Central Heating System Pressure Gauge
2.10 CONTROL PANEL
FIG. 2.22
FR020A
* Warning the flue analysis mode must only be selected by a
qualified service engineer.
DISPLAY CAUSE
A
A0 01 1No flame after safety time (7 seconds)
A
A0 03 3The heating flow temperature exceeds
103oC during operation
A
A9 97 7Problem with the electronic monitoring
A
A9 98 8Problem with the electronic monitoring
A
A9 99 9Problem with the electronic monitoring
E
E0 02 2Insufficient water pressure
E
E0 04 4Domestic hot water temperature probe in
open circuit
E
E0 05 5Domestic hot water temperature probe
short circuited
E
E0 06 6Heating flow temperature probe in open
circuit
E
E0 07 7Heating flow temperature probe short
circuited
E
E0 08 8Heating return temperature probe in open
circuit
E
E0 09 9Heating return temperature probe short
circuited
E
E2 20 0Flame detected with gas valve closed
E
E2 21 1Error in the electrical connection (live and
neutral crossed)
E
E3 33 3The air pressure switch is
closed before the ignition sequence
E
E3 34 4The air pressure switch does not close
when the fan runs
E
E9 99 9More than 5 RESETS of the boiler in 15
minutes.
The Control Panel has a 3 digit display, during normal
operation the display will show one of three things on the
two right hand digits;
During Stand-by (no demand for Central Heating or D.H.W.)
‘on’ will be shown on the display and no LEDs will light.
During a demand for Domestic Hot Water, the temperature of
the outgoing hot water is displayed in oC (e.g. 38) and the
summer mode LED will light (F - FIG. 2.22).
During a demand for Central Heating, the temperature of the
central heating flow will be displayed in oC (e.g. 65) and the
central heating mode LED will light (H- FIG.2.22).
During the operation of the flue analysis mode* the
display will show ‘sc’.
Should a fault occur the display will show the fault code
and one of two letters, for a non-volatile shutdown the
letter ‘A’will be shown followed by the two digit code for
the fault eg. ‘A02’and the red LED (G - FIG.2.22)will
light, a non-volatile shutdown will require the reset button
(D - FIG. 2.22) to be pushed before the boiler will attempt
to relight, should the boiler lockout again, the assistance
of an Authorised Service Engineer should be sought.
Should the boiler develop a fault that cannot be corrected
by resetting the boiler, the letter ‘E’will be displayed
followed by a two digit code (e.g. E33) indicating a
volatile shutdown code, in the event of such a shutdown,
the boiler will automatically resume operation once the
cause behind it is resolved. Should it not the assistance
of an Authorised Service Engineer would be required.
A list of the fault codes can be found opposite.
2.11 DIGITIAL DISPLAY AND FAULT CODES

19
In order to access the inside of the boiler, it is necessary
to unscrew the fastening screws “A” of the control panel
located on the lower part of the panel itself.
The control panel moves downward and when pulled
forward rotates on two lateral hinges.
The panel stays in a horizontal position, which allows
access to the inner parts of the boiler.
To dismantle the front casing panel it is necessary to:
1 - Remove the two screws “B”;
2 - Move the front casing panel up and lift forward.
2.12 REMOVING THE FRONT PANEL
To connect a room thermostat, it is necessary to:
1. - Open the control panel as indicated in SECTION 2.12.
2.- Remove the screws “A” from the terminal block on
the reverse of the control panel.
3. - Insert the thermostat cable through the cable
grommet and fasten it by means of the cable-clamp
provided.
4. - Connect the thermostat wires to the terminal block
(Diagram A).
5.- If a remote time clock is to be fitted, disconnect the
integral time clock from the P.C.B.
6. -Using a volt-free switching time clock, connect the
switching wires from the time clock following points 1-
4 above (Diagram B).
7. -If using an external time clock and room thermostat,
these must be connected in series as points 1-7
above (Diagram C).
Note: Only a low voltage room thermostat capable of
volt free switching must be used.
Factory fitted integral wiring must not be
disturbed when wiring external controls.
Do not run low voltage cables alongside
supply cables.
2.13 ROOM THERMOSTAT CONNECTION
FIG. 2.22
B
1
2
A
A
A

20
2.14 ELECTRICAL/SYSTEM DIAGRAMS
B - Summer/Winter Switch - Central Heating Temperature
Regulation
C - Connector for Remote Control (Climate Manager)
D - Domestic Hot Water Temperature Regulation
E - Soft-light Regulation
F - Maximum Central Heating Temperature Regulation
G - ON/OFF Selector
H - EEPROM
I - Time Clock Connector
L - Reset Push Button
M - Economy/Comfort Selector
N - EASY Teleservice (optional) P.C.B. Section
O - Display P.C.B. Connector
P - Transformer
Q- Modem Connection (optional - EASY Teleservice)
A01 - Circulation Pump
A02 - Fan
A03 - Spark Generator Power Supply
A04 - Gas Valve Power Supply
A05 - Motorised Valve
A07 - Flame Sensor
A08 - Central Heating Flow NTC
A09 - Domestic Hot Water NTC
A10 - Domestic Hot Water Flow Switch
A11 - Low Water Pressure Switch
A12 - Modulator
A13 - Air Pressure Switch
A14 - Overheat Thermostat
A15 - External Timer/Room Thermostat
A16 - Central Heating Return NTC
COLOURS:
Gy - Grey
Wh - White
Rd -Red
Br - Brown
Bl - Blue
Blk -Black
Pk - Pink
A - Dip Switch:
1 - Do Not Use (jumper is factory set in position B)
2 - Anti-Cycling Device Adjustment for Heating
Position A = 0 mins Position B = 2 mins
3 - Do Not Use (jumper is factory set in position B)
4 - Do Not Use (jumper is factory set in position B)
5 - Fan over-run selector (after D.H.W. is drawn)
Position A = ON Position B = OFF
6 - Do Not Use (jumper is factory set in position B)
FUSE
FUSE
1 2 4 5 63
ON
56
AB
CN203 CN206
CN206 CN205CN203 CN201 CN303 CN302
CN201 CN300
CN302
CN303
CN304
CN205
CN200
H
L
M
I
NO
P
Q

A16
Y/G
Blk Blk Blk Gry Gry Gry Gry Pnk Pnk Pnk Pnk
Gry or Bl
Wh Wh Wh Rd Blk Blk Blk Blk Brn
Brn
Brn
Bl Bl Bl Bl Blk Or Or

ATTENTION
When replacing the
P.C.B. disconnect the
EEPROM key (leave it
attached to the control
panel) and reconnect to
the new PCB.
H
FIG. 2.23