Ariston microGENUS HE 28 MFFI User guide

Installation and Servicing
Instructions
Type C Boilers
microGENUS HE 24 MFFI G.C.N:47-116-37
microGENUS HE 28 MFFI G.C.N:47-116-38
microGENUS HE 32 MFFI G.C.N:47-116-39
LEAVE THESE INSTRUCTIONS WITH
THE END-USER
Countryof 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.5
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
2.8.1 CONDENSATE REMOVAL PAGE.10
2.9 FLUE CONNECTION PAGE.12
2.9.1 FITTING THE COAXIAL FLUE
( 60/100 HORIZONTAL)PAGE.13
2.9.2 FITTING THE 5” FLUE
( 80/125 HORIZONTAL/VERTICAL)PAGE.14
2.9.3 FITTING THE COAXIAL FLUE
(60/100 VERTICAL)PAGE.15
2.9.4 FITTING THE TWIN PIPE ( 80/80) PAGE.16
2.10 CONTROL PANEL PAGE.21
2.11 DIGITAL DISPLAY AND FAULT CODES PAGE.21
2.12 REMOVING THE FRONT PANEL PAGE. 22
2.13 ROOM THERMOSTAT / REMOTE CLOCK
CONNECTION PAGE.22
2.14 FITTING THE DIGITAL CLOCK PAGE.23
2.15 SETTING THE MECHANICAL CLOCK PAGE.24
2.16 SETTING THE DIGITAL CLOCK PAGE.24
2.17 ELECTRICAL/SYSTEM DIAGRAMS PAGE.26
2.18 WATER CIRCUIT DIAGRAM PAGE.28
3. COMMISSIONING PAGE.29
3.1 INITIAL PREPARATION PAGE.29
3.2 INITIAL START-UP PAGE.31
3.3 OPERATIONAL ADJUSTMENTS PAGE.32
3.4 COMBUSTION ANALYSIS PAGE.32
3.5 PRODUCT OF COMBUSTION
DISCHARGE MONITORING PAGE.32
3.6 COMFORT MODE PAGE.32
3.7 BOILER SAFETY SYSTEMS PAGE.33
3.8 DRAINING THE SYSTEM PAGE.34
3.9 COMPLETION PAGE.35
3.10 OPERATIONAL CHECKS PAGE.35
3.11 INSTRUCTING THE END USER PAGE.36
4. GAS ADJUSTMENTS PAGE.37
4.1 CHANGING THE TYPE OF GAS PAGE.37
4.2 ADJUSTING THE GAS PRESSURES PAGE.37
5. MAINTENANCE PAGE.41
6. SERVICING INSTRUCTIONS PAGE.42
6.1 REPLACEMENT OF PARTS PAGE.42
6.2 TOGAIN GENERAL ACCESS PAGE.42
6.2.1 REMOVING THE FRONT PANEL PAGE.42
6.2.2 REMOVING THE SEALED CHAMBER
FRONT PANEL PAGE.43
6.2.3 REMOVING THE SIDE PANELS PAGE.43
6.3 ACCESS TO THE COMBUSTION CHAMBER PAGE.44
6.3.1 REMOVING THE COMBUSTION
CHAMBER PAGE.44
6.3.2 REMOVING THE BURNER AND JETS PAGE.44
6.3.3 REMOVING THE ELECTRODES PAGE.44
6.3.4 REMOVING THE MAIN HEAT EXCHANGER PAGE.45
6.3.5 REMOVING THE AIR PRESSURE SWITCH PAGE.46
6.3.6 REMOVING THE FAN PAGE.47
6.3.7 REMOVING THE FLUE /CONDENSATE
SENSOR PAGE.47
6.3.8 REMOVING THE RECUPERATOR PAGE.48
6.3.9 REMOVING THE RECUPERATOR HOUSING PAGE.49
6.3.10 REMOVING THE CONDENSATE TRAP PAGE.49
6.4 ACCESS TO THE GASVALVE PAGE.50
6.4.1 REMOVING THE SPARK GENERATOR PAGE.50
6.4.2 REMOVING THE GAS VALVE PAGE.50
6.5 ACCESS TO THE WATER CIRCUIT PAGE.51
6.5.1 REMOVING THE D.H.W. (SECONDARY)
EXCHANGER PAGE.51
6.5.2 REMOVING THE PUMP PRESSURE
SWITCH PAGE.52
6.5.3 REMOVING THE SAFETY VALVE PAGE.52
6.5.4 REMOVING THE AUTOMATIC AIR VENT PAGE. 53
6.5.5 REMOVING THE PUMP PAGE. 53
6.5.6 REMOVING THE PRESSURE GAUGE PAGE. 54
6.5.7 REMOVING THE EXPANSION VESSEL PAGE. 55
6.5.8 REMOVING THE OVERHEAT THERMOSTAT PAGE.55
6.5.9 REMOVING THE C.H. TEMPERATURE
SENSOR (N.T.C.) PAGE.56
6.5.10 REMOVING THE D.H.W. TEMPERATURE
SENSOR (N.T.C.) PAGE. 56
6.5.11 REMOVING THE DIVERTER VALVE
ACTUATOR PAGE.56
6.5.12 REMOVING THE D.H.W. FLOW
SWITCH PAGE.57
6.6 ACCESS TO THE CONTROL SYSTEM PAGE.57
6.6.1 CHECKING THE FUSES PAGE.57
6.6.2 REMOVING THE P
.C.B. PAGE.58
6.6.3 REMOVING THE TIME CLOCK PAGE.59
7. FAULT FINDING PAGE.60
7.1 FAULT FINDING GUIDE (FLOW-CHARTS)PAGE.60
8. SHORTSPARE PARTS LIST PAGE.63
9. TECHNICAL INFORMATION PAGE.66
10. BENCHMARK COMMISSIONING
CHECKLIST PAGE.68
11. SERVICE INTERVAL RECORD PAGE.69

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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
beconsulted 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 End
User 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 condensing combined appliance for the
production of central heating (C.H.) and domestic hot
water (D.H.W.).
This appliance must be used only for domestic use.
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.
MTS recommends the use of protective clothing when
installing and working on this appliance i.e. gloves.
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 inside of
the left hand casing panel.
The gas with which this appliance operates is also shown
on the label at the bottom of the boiler.
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. Condensate trap
14. Domestic Hot Water Temperature Probe
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. FlowSwitch
23. Condensate Trap Tube
24. Combustion Chamber
25. Condensate Sensor
26. Latent Heat Collector
27. Air Pressure Switch
28. 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.
Inthe United Kingdom the installation and initial start up
of the boiler must be by a CORGI Registered Installer in
accordance with the installation standards currently in
effect, as well as with any and all local health and safety
standards i.e. CORGI.
In the Republic of Ireland the installation and initial start
up of the appliance must be carried out by a Competent
Person in accordance with the current edition of I.S.813
“Domestic Gas Installations”, the current Building
Regulations, reference should also be made to the
current ETCI rules for electrical installation.
This appliance must be installed by a competent
installer in accordance with current Gas Safety
(installation & use) Regulations.
The installation of this appliance must be in accordance
with the relevant requirements of the Local Building
Regulations, the current I.E.E. Wiring Regulations, the
bylaws of the local water authority, in Scotland, in
accordance with the Building Standards (Scotland)
Regulation and Health and Safety document No.635
“Electricity at work regulations 1989” and in the Republic
of Ireland with the current edition of I.S.813, the Local
Building Regulations (IE).
C.O.S.H.H.
Materials used in the manufacture of this appliance are
non-hazardous and no special precautions are required
when servicing.
Installation should also comply with the following British
Standard Codes of Practice
and in the Republic of Ireland in accordance with the
following Codes of Practice:
BS 7593:1992 Treatment of water in domestic hot water
central heating systems
BS 5546:2000 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 6798:2000 Installation of gas fired hot water boilers
of rated input not exceeding 70kW
BS 6891:1998 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 the current I.E.E. Wiring Regulations, and
in Scotland, the electrical provisions of the Building
Regulations applicable in Scotland, 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 the appliance and any
electrical switch or appliance control, utilising mains
electricity should be situated so that it cannot be
touched by a person using the bath or shower,
specifically in accordance with current IEE Wiring
Regulations.
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 maybe
necessary.
BS 6798-2000 gives detailed guidance on this aspect.
Acompartment 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. However, as the appliance has many
functioning components, pay particular attention
when siting the appliance in room such as bedrooms
as operating noise may be a nuisance.
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 mark 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 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
120
LEGEND:
A=Central Heating Flow (3/4” - 22mm Copper Tail)
B=Domestic Hot Water Outlet (1/2” - 15mm Copper Tail)
C=Gas Inlet (3/4” - 15mm Copper Tail)
D=Domestic Cold Water Inlet (1/2” - 15mm Copper Tail)
E=Central Heating Return (3/4” - 22mm Copper Tail)
2.3 OVERALL DIMENSIONS
FIG. 2.1
* Clearance for Servicing 25mm if behind a temporary
closure i.e. door.

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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 9, where the
maximum absorbed power is also indicated. Ensure that
the connections for the live, neutral and earth wires
correspond with the indications in the diagram (Fig. 2.4).
The appliance electrical connections are situated on the
PCB, see Section 2.17
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 2.17.
Warning, this appliance must be earthed.
External wiring to the appliance must be carried out by a
competent person and be in accordance with the current
I.E.E. Regulations and applicable local regulations.
The appliance is supplied with a fly-lead already
connected, this must be connected to a 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
2.5.1. Drill the wall and plug using those supplied with
the connections kit, position the hanging bracket and
secure with the wall bolts supplied, assemble the
connection kit and secure to the wall. NOTE:Itis 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).
85 mm
220 mm
FIG. 2.4

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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 = Condensate discharge
G=Drain valve
H = Safety Valve Outlet
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.
FIG. 2.5
FIG. 2.6 KT007A
CENTRAL HEATING
Detailed recommendations are given in BS 6798:2000
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.
ABCDE
G
FH

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SAFETY VALVE DISCHARGE:
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
orany other type of public access.
AIRRELEASE 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 6 litres (1.3 gal) of expansion water. If
the heating circuit has an unusually high water content,
calculate the total expansion and add an additional
sealed expansion vessel with adequate capacity. This
should be located on the return pipe work as close as
possible to the pump inlet.
MAINS WATER FEED - CENTRAL HEATING:
Amethod 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.
VR003A
RESIDUAL HEAD OF THE BOILER DT20°C
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.
WATER TREATMENT
The boiler is equipped with a secondary heat exchanger
(recuperator) made from stainless steel as well as the
copper main heat exchanger.
The detailed recommendations for water treatment are
given in BS 7593:1992 (Treatment of water in domestic
hot water central heating systems); the following notes
are given for general guidance;
-If the boiler is installed on an existing system, any
unsuitable additives must be removed;
-Under no circumstances should the boiler be fired
before the system has been thoroughly flushed; the
flushing procedure must be in line with BS7593:1992.
We highly recommend the use of a flushing detergent
appropriate for the metals used in the circuit. These
include cleansers produced by Fernox and
BetzDearborn, whose function is to dissolve any
foreign matter that may be in the system;
In hard water areas or where large quantities of water
are in the system the treatment of the water to prevent
premature scaling of the main heat exchanger is
necessary.
The formation of scale strongly compromises the
efficiency of the thermic exchange because small
areas of scale cause a high increase of the
temperature of the metallic walls and therefore add to
the thermal stress of the heat exchanger.
Demineralised water is more aggressive so in this
FIG. 2.7

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1. Internal termination of condensate drainage pipe to
internal stack
situation it is necessary to treat the water with an
appropriate corrosion inhibitor.
-Any treatment of water by additives in the system for
frost protection or for corrosion inhibition has to be
absolutely suitable for all the metals used in the circuit.
The use of a corrosion inhibitor in the system such as
Fernox MB-1, BetzDeaborn Sentinel X100 or Fernox
System Inhibitor is recommended to prevent corrosion
(sludge) damaging the boiler and systems;
- If anti-freeze substances are to be used in the system,
check carefully that they are compatible with the metals
used in the circuit.
MTS suggests the use of suitable anti-freeze products
such as Fernox ALPHI 11, which will prevent rust and
incrustation taking place.
Periodically check the pH of the water/anti-freeze
mixture of the boiler circuit and replace it when the
amount measured is out of the range stipulated by the
manufacturer ( 7 < pH < 8).
DO NOT MIX DIFFERENT TYPES OF ANTI-FREEZE
- In under-floor systems, the use of plastic pipes without
protection against penetration of oxygen through the
walls can cause corrosion of the systems metal parts
(metal piping, boiler, etc), through the formation of
oxides and bacterial agents.
To prevent this problem, it is necessary to use pipes
with an “oxygen-proof barrier”, in accordance with
standards DIN 4726/4729. If pipes of this kind are
not used, keep the system separate byinstalling
heat exchangersof those with a specific system
water treatment.
IMPORTANT
Failure to carryout the water treatment procedure will
invalidate the appliance warranty.
CONDENSATE DISCHARGE:
Aflexible hose connected to the bottom of the boiler
should be inserted into a tundish (not supplied).
NOTE:ITMAYBE NECESSARYTO REMOVE THE CASING TO PULL
THE CONDENSATE HOSE OUT OF THE BOTTOM OF THE BOILER.
The condensate discharge hose from the boiler must
have a continuous fall of at least 2.5° and must be
connected to a visible tundish and inserted by at least
50mm into a suitable acid resistant pipe with a nominal
diameter of 32mm e.g. plastic waste pipe or overflow
pipe. The condensate discharge pipe must have a
continuous fall and preferably be installed and terminated
within the building to prevent freezing.
The discharge pipe must be terminated in one of the
following positions, allowing for a safe discharge:
i) Connecting in to an internal soil stack (at least 450 mm
above the invert of the stack). A trap giving a water
seal of at least 75 mm must be incorporated into the
pipe run, there also must be an air break upstream of
the trap i.e. tundish.
2.8.1 CONDENSATE REMIOVAL

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3. External termination of condensate drainage pipe via
internal discharge branch (e.g. sink waste - proprietary fitting).
4. External termination of condensate drainage pipe via
condensate siphon
2. External termination of condensate drainage pipe via
internal discharge branch (e.g. sink waste) and condensate
siphon
ii) Connecting into the waste system of the building such
asawashing machine or sink trap. The connection
must be upstream of the washing machine/sink (If the
connection is down stream of the waste trap then an
additional trap giving a minimum water seal of 75 mm
and an air break must be incorporated in the pipe run,
as above.
iii)Terminating into a gully, below the grid level but above
the water level.
iv)Into a soakway.
NOTE: If any condensate pipe work is to be installed
externally, then it should be kept to a minimum and be
insulated with a waterproof insulation and have a
continuous fall.
Some examples of the type of condensate drains can
be found in this section.

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2.9. CONNECTING THE FLUE
IMPORTANT!!
BEFORE CONNECTING THE FLUE,ENSURE THAT 1LITRE OF
WATER HAS BEEN POURED INTO THE EXHAUST CONNECTION TO
FILL THE CONDENSATE TRAP (FIG.2.8). SHOULD THE TRAP BE
EMPTY THERE IS A TEMPORARY RISK OF FLUE GASSES
ESCAPING INTO THE ROOM.
FIG. 2.8
4
Ø60/100 mm
Fig. 2.10
TERMINAL POSITION mm
A - Directly below an open window or other opening 300
B - Below gutters, solid pipes or drain pipes 75
C - Beloweaves 200
D - From vertical drain pipes and soil pipes 75
E - From internal or external corners 300
F - Above ground on a public walkway or patio 2100
G - From a surface facing a terminal 2500
H - From a terminal facing a terminal 2500
I - Vertically from a terminal in the same wall 1500
J - Horizontally from a terminal in the same wall 300
K - Horizontally from an opening window 300
L - Fixed by vertical flue terminal
E
E
FLUE SYSTEM
The provision for satisfactory flue termination must be made
as described in BS 5440-1.
The appliance must be installed so that the flue terminal is
exposed to outdoor 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, it must also be located in a place not likely to cause
nuisance.
In cold or humid weather water vapour may condense on
leaving the flue terminal.
The effect of such “steaming” must be considered.
If the terminal is 2.1 metres above a balcony, above ground
or above a flat roof to which people have access, then a
suitable stainless steel terminal guard must be fitted.
The minimum acceptable spacing from the terminal to
obstructions and ventilation openings are specified in Fig.
2.9.
FIG. 2.9

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Warning
The exhaust gas ducts must not be in contact with or close to
inflammable material and must not pass through building
structures or walls made of inflammable material.
When replacing an old appliance, the flue system must be
changed.
Important
Ensure that the flue is not blocked.
Ensure that the flue is supported and
assembled in accordance with these
instructions.
2.9.1 FITTING THE COAXIAL FLUE
(Ø 60 / 100 HORIZONTAL)
SEE PAGE 19 FOR MAX AND MIN FLUE RUNS
Installation without extension
Installation with extension
Fig. 2.11
Fig. 2.12
118
Level
Level
PART NO: 3318073
CONTENTS:
1XSILICONE O-RING (60mm)
1XELBOW (90O)
2XWALL SEALS (INTERNAL & EXTERNAL)
1XFLUE PIPE INCLUDING TERMINAL (1 METRE -60/100)
2XFLUE CLAMPS
4XSCREWS
2x Seals
Once the boiler has been positioned on the wall, insert
the elbowinto the socket 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 (Fig
2.13) secure the elbow to the boiler.
The 1 metre horizontal flue kit (3318073) supplied is
suitable for an exact Xdimension of 823mm.
Measure the distance from the face of the external wall
to the face of the flue elbow (X - Fig 2.10), this figure
must now be subtracted from 815mm, you now have
the total amount to be cut from the plain end of the flue.
Draw a circle around the outer flue and cut the flue to
the required length taking care not to cut the inner flue,
next cut the inner flue ensuring that the length between
the inner and outer flue is maintained. (Fig 2.13).
e.g.
X=555mm
823-555 = 268mm (Length to be cut from the plain
end of the flue).

14
Fig. 2.13
2.9.2 FITTING THE 5” FLUE
(Ø 80 / 125 HORIZONTAL/VERTICAL)
SEE PAGE 19 FOR MAX AND MIN FLUE RUNS CONTENTS:
HORIZONTAL KIT -3318095
3XSILICONE O-RINGS (60mm, 80mm & 125mm)
1X90OELBOW (HORIZONTAL ONLY)
1XADAPTOR (60/100 - 80/125MM)
1XHORIZONTAL FLUE PIPE (INCLUDING TERMINAL)
(80/125mm)
2XWALL SEALS (INTERNAL & EXTERNAL)
2XFLUE CLAMPS
2XSEALS
4XSCREWS
VERTICAL KIT -3318080 (BLACK) / 3318081 (RED)
1XVERTICAL FLUE PIPE (INCL.TERMINAL)(80/125MM)
1XADAPTOR (60/100 - 80/125)
1XSILICONE O-RING (60MM)
Should the flue require extending, the flue connections are
push fit, however, one flue bracket should be used to
secure each metre of flue.
Once the boiler has been positioned on the wall, it is
necessary to insert the Ø80/125 adaptor (FIG. 2.14)
raised horizontal and vertical flue runs into the boiler flue
socket (not supplied with flue kit - PartNo 3318095).
Push the adaptor onto the boilers flue connection, grease
the seals then add extensions or elbows as required,
secure the adaptor, using the clamp and screws provided.
Tofit extensions or elbows it is first necessaryto ensure
that the lip seal is fitted correctly into the inner flue, once
verified, it is simply necessary to push them together, no
Screws
Clamp
Seal
Fig. 2.14
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 the flue through
the hole, once the wall seal has passed through the
hole, pull the flue back into the elbow (ensuring that the
flue seal is not dislodged) until the external wall seal is
flush with the wall, and that the flue is securely located
into the elbow, finally secure the flue to the elbow with
the clamp provided. Alternatively, the flue can be
installed from outside of the building, the grey outer
seal being fitted last.

15
NOTE:SEE PAGE 19 FOR MAXIMUM AND MINIMUM FLUE
RUNS.
PART NO: 33108080 (BLACK) / 3318081 (RED)
CONTENTS:
1XSILICONE O-RING (60mm)
1XCONICAL ADAPTOR (60/100mm)
1XVERTICAL FLUE KIT (80/125mm)
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.
The Vertical flue kits useable lengths with the pitched
roof flashings are indicated in Fig. 2.17.
Before proceeding to fit the flue, ensure that the
maximum flue length has not been exceeded (See
the tables on Page 19) and that all elbows and bends
have been taken into consideration, the maximum
flue length is 4 metres, for each additional 90oelbow
1metre must be subtracted from the total flue length,
and for each 45o0.5 metres must be subtracted from
the total flue length (the height of the vertical
adaptor and a 45obend can be seen in Fig. 2.18).
Markthe position of the flue hole in the ceiling and/or
2.9.3. FITTING THE COAXIAL FLUE
(Ø 60 / 100 VERTICAL)
Fig. 2.15 Fig. 2.16
Fig. 2.17
clamps are necessary to secure the flue components.
Before proceeding to fit the flue, ensure that the
maximum flue length has not been exceeded (See the
tables on Page 19) and that all elbows and bends have
been taken into consideration, the maximum flue length
is 10 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 height of the vertical adaptor and a
45obend can be seen in Fig. 2.15 and a 90obend
(raised horziontal only) in Fig. 2.16).
NOTE:DO NOT CUT THE VERTICAL FLUE KIT.

16
2.9.4. FITTING THE TWIN PIPE (Ø80 / 80) NOTE:SEE PAGE 19 FOR MAXIMUM AND MINIMUM FLUE RUNS.
Where it is not possible to terminate the flue within the
distance permitted for coaxial flues, the twin flue pipe can
be used byfitting a special adaptor to the flue connector
and using the aperture for the air intake located on top of
the combustion chamber.
Always ensure that the flue is adequately supported, using
one flue bracket per extension and avoiding low points.
(MTS supply suitable clamps as Part No. 705778).
Toutilise the exhaust manifold it is necessary to connect
the adaptor (Part No: 3318017) to the exhaust manifold
and secure with the clamp (see FIG. 2.18A), add elbows or
extensions as required.
To utilise the air intake it is necessary to:
Remove the ‘knockout’ of the air intake by cutting it with a
suitable knife (FIG. 2.18B).
Insert the elbow/flue pipe into the air intake until it stops.
Fig. 2.18
roof (see Fig. 2.16 for distance from the wall to the centre
ofthe flue).
Cut a 120mm diameter hole through the ceiling and/or
roof and fit the flashing plate to the roof.
DO NOT cut the vertical flue kit.
Toconnect the vertical flue kit directly to the boiler, place
the vertical starter kit (Part No. 3318079) (see Fig. 2.17)
onto the exhaust manifold and secure with the clamp, fit
the vertical adaptor onto the vertical starter kit (note: there
is no need to use a clamp to secure this as it is a push fit
connection), 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. 3318077),500mm (Part No. 3318078)
and 160mm lengths, they must be connected directly to
the vertical starter kit 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
inner and outer flue remain flush.
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 by using 1 flue bracket per extension.
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.
Fig. 2.18A

17
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.
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 (greasing the seal will aid assembly).
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. 3318089).
When running the twin flue pipe vertically.
It is not possible to terminate concentrically horizontally.
Termination is only possible with separate air and exhaust
terminals.
When siting the twin flue pipe, the air intake and exhaust
terminals must terminate on the same wall, the centres of
the terminals must be a minimum of 280 mm apart and
the air intake must not be sited above the exhaust
terminal (refer to Fig. 2.22). The air intake pipe can be run
horizontally,however,the terminal and the final 1 metre of
flue must be installed either horizontally or with a slight fall
away from the boiler to avoid rain ingress.
It is also strongly recommended that the air intakepipe 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 40 metres,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
40 metres.
The maximum length is reached by combining the total
lengths of both the air intake and exhaust pipes. Therefore
amaximum 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 2.2 metres must
be subtracted from the total length and for each 45oelbow
1.4 metres must be subtracted from the total flue length.
Some of the acceptable flue configurations are detailed on
page 20.
For further information relating to flue runs not illustrated,
please contact the Technical Department on 0870 241
8180.
Fig. 2.18B

18
For coaxial systems, the maximum development value,
mentioned in the table below also takes into account an
elbow.
For twin flue systems the maximum development value,
mentioned in the table includes the exhaust gas/air intake
terminal.
Type 5 outlets should respect the following instructions:
1- Use the same ø 80 mm flue pipes for the air intakes
and exhaust gas ducts.
2- If you need to insert elbows in the air intake and
exhaust gas ducts, you should consider for each one
the equivalent length to be included in the calculation
of developed length.
3- The exhaust gas duct should jut above the roof by at
least 0.5 m.
4- The intakeand exhaust gas ducts in Type 5 must be
installed on the same wall, or where the exhaust is
vertical and the air intake horizontal, the terminals must
be on the same side of the building.
ø 100
60 mm
In the event that twin flue pipes are used, and the boiler
has a side clearance of less than 60mm from the wall, it
is necessary to cut a larger diameter hole for the flue
pipe, this should be ø10 cm, this will then allow for easier
assembly of the air intake elbow and the tube outside the
wall (see Fig. 2.20).
Fig. 2.20
In the event that the air intake and exhaust are run to the
left, it will be necessary to reduce the height of the air
intake by cutting 20mm from the base of the air intake
elbow (see Fig. 2.19)
Fig. 2.19
The flue restrictor is factory fitted in the exhaust manifold
on the boiler. Please refer to the table on page 19 to
determine whether it will be necessary to remove it.
Toremove the restrictor it is simply necessary to lift the
restrictor from the exhuast manifold (Fig. 2.20A)
Fig. 2.20A

19
24 MFFI ExhaustType
Do not remove the
ø40 mm
Restrictor
Remove the
Restrictor
(Fig.2.20A)
Maximum Flue
Length
Length
Reduction 45o
elbow (m)
Length
Reduction 90o
elbow (m)
Coaxial
Systems
ø60/100
Type 1
Between
500 mm - 1 m
Between
1m-4m 4 m 0.5 m 1.0 m
Type 2
Type 3
Coaxial
Systems
ø80/125
Type 1
TBC TBC 10 m TBC TBC
Type 2
Type 3
Twin Pipe
Systems
ø80/80
Type 4 Between
1m - 10 m Between
10 m - 40 m 40 m 1.4 m 2.2 m
Type 5 Between
1m - 10 m Between
10 m - 40 m 40 m 1.4 m 2.2 m
28 MFFI ExhaustType
Do not remove the
ø41 mm
Restrictor
Remove the
Restrictor
(Fig.2.20A)
Maximum Flue
Length
Length
Reduction 45o
elbow(m)
Length
Reduction 90o
elbow(m)
Coaxial
Systems
ø60/100
Type 1
Between
500 mm - 1 m
Between
1m-4m 4 m 0.5 m 1.0 m
Type 2
Type 3
Coaxial
Systems
ø80/125
Type 1
TBC TBC 10 m TBC TBC
Type 2
Type 3
Twin Pipe
Systems
ø80/80
Type 4 Between
1m - 10 m Between
10 m - 40 m 40 m 1.4 m 2.2 m
Type 5 Between
1m - 10 m Between
10 m - 40 m 40 m 1.4 m 2.2 m
32 MFFI ExhaustType
Do not remove the
ø43 mm
Restrictor
Remove the
Restrictor
(Fig.2.20A)
Maximum Flue
Length
Length
Reduction 45o
elbow (m)
Length
Reduction 90o
elbow (m)
Coaxial
Systems
ø60/100
Type 1
Between
500 mm - 1 m
Between
1m-4m 4 m 0.5 m 1.0 m
Type 2
Type 3
Coaxial
Systems
ø80/125
Type 1
TBC TBC 10 m TBC TBC
Type 2
Type 3
Twin Pipe
Systems
ø80/80
Type 4 Between
1m - 10 m Between
10 m - 40 m 40 m 1.4 m 2.2 m
Type 5 Between
1m - 10 m Between
10 m - 40 m 40 m 1.4 m 2.2 m

20
Fig. 2.22
NOTE: DRAWINGS ARE INDICATIVE OF FLUEING OPTIONS ONLY.
TYPE 1
TYPE 5
TYPE 4
TYPE 3
TYPE 2
FIG. 2.21