Ariston Genus 27 Plus User manual

400
Installation Instructions
Type C Boilers
G.C.N: 47-116-11
LEAVETHESE INSTRUCTIONS
WITHTHE END USER
Country of destination: GB

2400
TABLE OF CONTENTS 1. GENERAL INFORMATION
1.1 General Instructions
1.2 Overall View
2. INSTALLATION
2.1 Reference Standards
2.2 Siting the Appliance
2.3 Overall Dimensions
2.4 Clearances
2.5 Mounting the Appliance
2.6 Electrical Connection
2.7 Gas Connection
2.8 Water Connections
2.9 Flue Connection
2.10 Room Thermostat Connection
2.11 Electrical/System Diagrams
2.12 Water Circuit Diagrams
3. COMMISSIONING
3.1 Initial Preparation
3.2 Removing the Casing
3.3 Control Panel
3.4 Initial Start-up
3.5 Operational Adjustments
3.6 Combustion Analysis
3.7 Fume Discharge Monitoring
3.8 Boiler Safety Systems
3.9 Draining the System
4. GAS ADJUSTMENTS
- Gas Adjustment Table
4.1 Changing the Type of Gas
5. MAINTENANCE
6. TECHNICAL INFORMATION

3
400
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 User’s Manual.
Read the instructions and recommendations in these Installation Instructions careful-
ly 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 our
Servicing Centre 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 domes-
tic hot water (D.H.W.).
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 on pages 4-5 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 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 allow children or inexperienced persons to use the appliance without super-
vision.
If you smell gas in the room, do not turn on 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 (on 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 carriyng 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 Centre and request the use of origi-
nal spare parts.For in-guarantee repairs contact MTS (GB) Limited
Check the following at least once a year:
1 - Check the seal of water connections, replacing the gaskets if necessary.
2- Check the seal of the gas connections, replacing the gaskets if necessary.
3- Check the general condition of the appliance and of the combustion chamber
visually.
4 - Visual check of the combustion:clean burners if necessary.
5- With reference to point 3, dismantle and clean the combustion chamber if nec-
essary.
1. GENERAL
INFORMATION
1.1 General Information

4400
Legend:
1. Air Pressure Switch
2. Fan
3. Main Heat Exchanger
4. Combustion Chamber
5. Ignition Electrodes and
Detection Electrodes
6. Burner
7. Automatic air release valve
8. Gas Valve
9. Spark Generator
10. Circulation Pump
11. Motorised Valve with by-pass
12. Main Circuit Flow Switch
13. Safety Valve (3 bar)
14. Low pressure switch
15. Expansion relief valve (6 bar)
16. C.H. expansion Vessel
17. D.H.W. expansion Vessel
18. Drain point
19. C.H.W. Probe
20. Overheat Thermostat
21. D.H.W. Storage with insulation shell
Fig. 1.1
1.2 OverallView
6 - With reference to point 4, dismantle and clean the injectors if necessary.
7- Visual check of the primary heat exchanger:
- check for overheating of the exchangers fins;
- clean the exhaust side of the exchanger and fan if necessary.
8- Regulate the gas pressure, ignition pressure, partial flame, maximum flame.
9- Check proper operation of the heating safety system:
- maximum safety temperature;
- maximum safety pressure.
10 - Check the proper operation of the gas safety system:
- gas or flame safety device;
- gas valve safety device.
11 - Check that the electrical connections have been made in compliance wit h the
instructions shown in the Installation Instructions.
12 - Check the efficiency of the hot water supply (flow and temperature).
13 - Check pressure in the Domestic ExpansionVessel and top up as necessary.
14 - Check manually by turning the test knob the Temperature & Pressure ReliefValve.
15 - Check manually by turning the test knob the Expansion Relief Valve.
16 - Check discharge pipes from both the central heating and domestic hot water
for obstructions.
17 - Check general operation of the appliance.
18 - Check the exhaust system for the combustion products.
IN003A

5
The technical information and instructions provided herein below are intended for
the installer so that the unit may be installed correctly and safely.
WATER REGULATIONS
These regulations ensure a good supply of wholesome water, and that only approved
materials, pipes and fittings are used to convey water.
BUILDING REGULATIONS
These are a statutory document and take priority over all other regulations and recom-
mendations.The installation of an unvented hot water storage cylinder is classified as a
"Controlled Service" and Regulation G3 applies. To meet the requirements of the
Regulation, installation of an unvented system should be undertaken by a "competent
installer".
All installations of unvented hot water storage systems having a capacity of more than
15 litres should be notified to the relevant Local Authority by means of building notice or
by the submission of full plans. It is important to note that it is a criminal offense to
install an unvented hot water storage system without notifying the Local Authority.
The installation and initial startup of the boiler must be by a CORGI Approved
Installer in compliance with the installation standards currently in effect, as well as
with any and all local health and safety standards i.e.CORGI.
The installation of this appliance must be in accordance with the relevant require-
ments of the current Gas Safety (installation & use) Regulations, the Local Building
Regulations, the current I.E.E. Wiring Regulations, the byelaws of the local water
authority, and in Scotland, in accordance with the Building Standards (Scotland)
Regulation and Health and Safety document No.635 “Electricity at work regs.1989”.
Installation should also comply with the following British Standard Codes of Practice:
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 con-
taining a bath or shower.
Where a room-sealed appliance is installed in a room containing a bath or
shower the boiler 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.
The location must permit adequate space for servicing and air circulation around the
appliance as indicated in paragraph 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 an 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 appli-
ance is installed) can be installed in any type of room.
There are no limitations with respect to ventilation and the volume of the room itself.
The boiler must be installed on a solid, permanent wall to prevent access to the
electrical parts (when live) through the aperture on the back frame.
2. INSTALLATION
2.1 Reference Standards
2.2 Siting the Appliance
400
BS 7593:1992 Treatment of water in domestic hot water central
heating systems
BS 5546:1990 Installation of hot water supplies for domestic
purpoes
BS 5440-1:1990 Flues
BS 5440-2:1989 Air supply
BS 5449:1990 Forced circulation hot water systems
BS 6789:1987 Installation of gas fired hot water boilers
BS 6891:1989 Gas installations
BS 7671:1992 IEE wiring regulations
BS 4814:1990 Specification for expansion vessels
BS 5482:1994 Installation of LPG

6400
Fasten the boiler in place using the template and anchors supplied
with the unit. It is highly recommended that a spirit level be used to
position the boiler so that it is perfectly level.
For additional information, please consult the instructions contained in
the connection kit and the flue kit.
2.5 Mounting the Appliance
2.6 Electrical Connection
Fig. 2.3
Legend:
A = Central Heating Return (3/4”)
B = Central Heating Flow (3/4”)
C = Gas Inlet (3/4”)
D = Domestic Hot Water Outlet (1/2”)
E = Secondary return (1/2”)
F = Domestic Cold Water Inlet (1/2”)
2.3 Overall Dimensions
In order to allow for access to the interior of the boiler for maintenance
purposes, the boiler must be installed in compliance with the clear-
ance requirements indicated in the diagram below.
2.4 Clearances
Fig. 2.1
Fig. 2.2
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 techni-
cal data table (7), where the maximum absorbed power is also indicat-
ed. Make sure that the connections for the neutral and live wires cor-
respond to the indications in the diagram. The appliance electrical
connections are situated on the reverse of the control panel (see the
servicing manual for further information)
Important!
In the event that the power supply cord must be changed, replace it
with one with the same specifications. Make the connections to the
terminal board located within the control panel, as follows:
- The yellow-green wire should be connected to the terminal marked
with the earth symbol; make sure to re-use the ferrule mounted on the
other supply cord;
- The blue wire should be connected to the terminal marked “N”;
- The brown wire should be connected to the terminal marked “L”.
Note: The diagrams for the electrical system are indicated in section
2.11.
Warning, this appliance must be earthed.
External wiring to the appliance must be carried out by a qualified
technician and be in accordance with the current I.E.E. Regulations
and applicable local regulations. The Genus range of boilers are sup-
plied for connection to a 230 V~ 50 Hz supply.
The supply must be fused at 3 A.
The method of connection to the electricity supply must facilitate com-
plete 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
Fig. 2.1
QT003A
DM002A
VR004A

7
400
Central Heating
Detailed recommendations are given in BS 6798:1987 and BS 5449-1:1990, the fol-
lowing 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 natura col-
lecting 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 cock-type valves
within the system.
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.The taps must be at least 15mm nominal size an manufactured in
accordance with BS 2870:1980.
Safety Valve Discharge:
The discharge should terminate facing downwards 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.
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 sup-
ply 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.
2.8 Water Connections
A
CBD
E
HI
F
View of the Boiler Connections
Fig. 2.4
unswitched shuttered socket outlet both complying with BS 1363.
The point of connection to the Electricity supply must be readily accessible and adja-
cent to the appliance unless the appliance is installed in a bathroom when this must
be sited outside the bathroom.
Legend:
A = Central Heating Return (3/4”)
B = Central Heating Flow (3/4”)
C = Gas Inlet (3/4”)
D = Domestic Hot Water Outlet (1/2”)
E = Secondary return (1/2”)
F = Domestic Cold Water Inlet (1/2”)
H = Central Heating Discharge
I = Domestic Hot Water Discharge
SC002A

8400
Discharge pipework
1) The tundish must be installed directly below the discharge outlet connection of the
boiler.The tundish must also be in a position visible to the occupants, and positioned
away from any electrical devices. The discharge pipe from the tundish should termi-
nate in a safe place where there is no risk to persons in the vicinity of the discharge
and to be of metal.
2) Discharge pipes from the temperature & pressure relief are expansion relief valve are
joined together within the appliance.
3) The pipe diameter must be at least one pipe size larger than the nominal outlet size of
the safety device unless it's total equivalent hydraulic resistance exceeds that of a
straight pipe 9m long.
I.e. Discharge pipes between 9m and 18m equivalent resistance length should be at
least 2 sizes larger than the nominal outlet size of the safety device. Between 18m
and 27m at least 3 sizes larger, and so on.
Bends must be taken into account in calculating the flow resistance.
See fig. 2.4.1 and Table 1.
4) The discharge pipe must have a vertical section of pipe at least 300m in length, below
the tundish before any elbows or bends in the pipework.
5) The discharge pipe must be installed with a continuous fall.
6) The discharge must be visible at both the tundish and the final point of discharge, but
where this is not possible or practically difficult; there should be clear visibility at one
or other of these locations.Examples of acceptance are:
i) Ideally below a fixed grating and above the water seal in a trapped gully.
ii) Downward discharges at a low level; i.e. up to 100mm above external surfaces such
as car parks, hard standings, grassed areas etc. These are acceptable providing that
where children may play or otherwise come into contact with discharges, a wire cage or
similar guard is positioned to prevent contact, whilst maintaining visibility.
iii) Discharges at high level; I.e. into a metal hopper and metal down pipe with the end
of the discharge pipe clearly visible (tundish visible or not). Or onto a roof capable of
withstanding high temperature discharges of water 3m from any plastic guttering sys-
tems that would take such a discharge (tundish visible).
iv) Where a single pipe serves a number of discharges, such as in blocks of flats, the
number served should be limited to not more than 6 systems so that any installation
can be traced reasonably easily. The single common discharge pipe should be at
least one pipe size large than the largest individual discharge pipe to be connected. If
unvented hot water storage systems are installed where discharges from safety
devices may not be apparent I.e.in dwellings occupied by the blind, infirm or disabled
people, consideration should be given to the installation of an electronically operated
device to warn when discharge takes place.
Note: The discharge will consist of scalding water and steam. Asphalt, roofing felt
and non-metallic rainwater goods may be damaged by such discharges.
Warningr
The outlet from the temperature & pressure relief valve must not be used for any other
purpose.
The temperature & pressure relief valve must not be removed in any circumstances.
Any of the above will totally invalidate the warranty.
Note
The discharge from the central heating and domestic hot water systems may be
joined together after the tundish.
500 mm Max.
300 mm
Min.
Temperature & pressure
relief valve Metal discharge pipe (D1) from
temperature & pressure relief valve.
to tundish.
Metal discharge pipe (D2) from tundish
with continuous fall.SeeTable 2 and worked
example.
Tundish
Fixed grating
Trapped gulley
Discharge below
fixed grating.
(see page 6 for
alternative points
of discharge).
Table 1. Sizing of copper discharge pipe
“D2”for common temperature
valve outlet sizes.
WORKED EXAMPLE
The example below is for a G 1/2Temperature & Pressure Relief valve with a dis-
charge pipe (D2) having 4 no.elbows and length of 7m from the Tundish to the point
of discharge.From Table 1
Maximum resistance allowed for a straight length of 22mm copper discharge pipe
(D2) from G 1/2 T & P valve is 9m.
Subtract the resistance for 4 no. 22mm elbows at 0.8m each = 3.2m.
Therefore the maximum permitted length equates to: 5.8m.
As 5.8m is less than the actual length of 7m
therefore calculate the next largest size.
Maximum resistance allowed for a straight
length of 28mm pipe (D2) from G 1/2 T & P
valve equates to: 18m.
Subtract the resistance for 4 no. 28mm elbow
at 1.0m each = 4m.
Therefore the maximum permitted length
equates to: 14m
As the actual length is 7m, a 28mm (D2) cop-
per pipe will be satisfactory.
Valve outlet size Minimum size of
discharge pipe D1* Minimum size of discharge pipe D2*
from tundish
Maximum
resistance allowed,
expressed as a
length of pipe (i.e.
no elbow or bends)
Resistance created
by each elbow or
bend
G 1/2 15 mm 22 mm
28 mm
35 mm
Up to 9 m
Up to 18 m
Up to 27 m
0.8 m
1.0 m
1.4 m
G 3/4 22 mm 28 mm
35 mm
42 mm
Up to 9 m
Up to 18 m
Up to 27 m
1.0 m
1.4 m
1.7 m
G 1 28 mm 35 mm
42 mm
54 mm
Up to 9 m
Up to 18 m
Up to 27 m
1.4 m
1.7 m
2.3 m
Fig. 2.4.1
SH005A
TB004A

9
400
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 value when the system is heated.
It can accept up to 7 l (1.5 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.
Mains Water Feed - Central Heating:
There must be no direct connection to the mains water supply even through a
non-return valve, without the approval of the Local Water Authority.
Filling:
A temporary method for initially filling the system and replacing lost water during
servicing and initial filling (complying to current water regulations) must be pro-
vided. The flexible hose must be removed once the system has been filled. The
D.H.W. inlet valve on the connection kit has two postions, one for winter and one
for the summer. This enables the flow-rate through the appliance to be adjusted
so that a sensible D.H.W. temperature may be achieved throughout the year.
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.
Note: This appliance is capable of producing domestic hot water of up to
70˚C. For extra security against scalding a thermostatic blending valve
may be installed on the domestic hot water outlet.
Secondary Return
The secondary return can be used as an option. A Non Return Valve (not supplied) must
be fitted to prevent back flow and a Bronze Pump will be needed in conjunction with a
Pipe Thermostat to circulate the hot water (both not supplied).
Residual Head of the Boiler
A: Gas inlet
B: C.H.W. return
C: C.H.W. flow
D: D.H.W. secondary return
E: D.H.W. flow
F: D.H. inlet
1 - Gas meter inlet cock
2 - Gas meter
3 - Gas meter outlet cock
4 - Internal gas cock
5 - Appliance gas inlet cock
6 - D.W. inlet cock
7 - D.H.W. expansion vessel
8 - cock
9 - Secondary return pump
10 - Thermostat
11 - Time control clock
12 - Radiator control clock
13 - Holder
14 - Air release valve
15 - Drain valve
16 - T&P valve
17 - Safety valve
18 - Tundish
Fig. 2.5
Fig. 2.5.1
VR005A
SH006A

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 dis-
colouration that might occur on buildings in the vicinity.
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 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 appli-
ance model number.
A suitable terminal guard is available from:
TOWER FLUE COMPONENTS
Morley Road
Tonbridge
KentTN9 1RA
The minimum acceptable spacing from the terminal to obstructions
and ventilation openings are specified in Fig.2.6
The boiler is designed to be connected to a coaxial flue discharge
system.
TERMINAL POSITION mm
A - Directly below an open 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 75
F - From internal or external corners 300
G - Above ground or below 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
A
BC
D
E
F
G
J
K
HI
L
GF
Fig. 2.6
2.9 Flue Connections
10 400
In addition, it is also possible to use a split
system by fitting a special adapter to the
flue discharge collar and using one of the
apertures for the air vent intake located
on the top part of the combustion cham-
ber (A).
Fig. 2.8
Fig. 2.7
FU010A
FU011A
FU012A

In Fig. 2.11 below, several different
types of flue systems are shown.
For additional information regarding the
flue accessories, please consult the
Flue Pipe Accessories manual.
Fig. 2.11
In calculating the lengths of the pipes, the maximum length must also take into con-
sideration the values for the exhaust/air intake end terminals, as well as 90°elbows
for coaxial systems.
The C52 types must comply with the following requirements:
1. The discharge/intake vent pipes must have the same diameter of ø80 mm.
2. If an elbow is inserted into the discharge/ventilation system, the calculation of the
overall extension must take into consideration the values for each curve, as indi-
cated in the table.
3. The exhaust pipe must extend at least 0.5 m above the ridge of the roof if it is
located on a side other than that for the air intake (this is not obligatory if the
exhaust and air intake pipes are located on the same side of the building).
(*) L = Length of Piping
C12 (xx) 4 m ø60 /100 NO
Coaxial
System C32 (xx) 4 m ø60 /100 NO
C42 (xx) 4 m ø60 /100 NO
C12 (xy) 34 m ø80 L < 4.5 m L > 6.6 m
C32 (xy) 34 m ø80 L < 4.5 m L > 6.6 m
Split
Systems C42 (xy) 34 m ø80 L < 4.5 m L > 6.6 m
C52 (xy) 56 m ø80 L < 8 m L > 5.8 m
Maximum Extension
Exhaust/Air
ExhaustType Diameter of Pipes
(mm)
Use of ø42 mm Restictor
on Delivery Side Risk of Condensation
Forming
11
400
This procedure must be done as follows:
1 - Remove the air vent intake in the area
indicated in Fig. 2.9, by breaking the
perforated ring.
2 - Use a tool to grasp the lid and remove
it completely.
3 - Clean any burrs or sharp edges with a
knife or an appropriate tool.
A
Fig. 2.9 Fig. 2.10
FU013A
FU014A

12 400
2.10 RoomThermostat
Connection
1
In order to perform this procedure, remove the boiler casing as indicated in
section 3.2.Then proceed as follows:
1Rotate down the control panel.
2Open the cover “A”on the left hand side of the compartment.
3Insert the wire for the connection of the room thermostat into the cable
clamp “B”, as indicated in photo 3.
4Remove the grommet “C”shown in the photo 4, make a hole in it and pass
the room thermostat wire through.
5Remove the link located in the terminal block and connect the wire.
6Replace the grommet and the terminal block to their original positions,
close the cover on the grommet compartment and fasten the wire-clamp “B”in
place.
7If a remote time clock is to be fitted, disconnect the integral time clock plug
from the P.C.B.
8Using a volt-free switching time clock, connect the switching wires from the
time clock following points 1-6 above.
9If using a time clock and room thermostat, these must be connected in
series as per points 1-8 above.
Note: Only a two-wire type room thermostat can be used.
An anti-frost device is built-in to the appliance’s electronic
regulation system.
2
3B
A
4C
5
6
B
TA001A

13
2.11 Electrical Diagram
T
D.H.W. Heating
+ D.H.W.
FlueTest
operating
modes
Heating
AT
BT
Legend:
AT = High Voltage P.C.B.
BT = Low Voltage P.C.B.
A = Remote Connector Kit
B = Flame Failure L.E.D.
C = Insufficient Water Pressure L.E.D.
D = WaterTemperature Indicator L.E.D.s
E = Overheat Thermostat Warning L.E.D.
F = System Reset Button
G = Selector Knob for Operating Mode
H = Domestic Hot Water Temp. Adjustment
I = Central Heating Temp. Adjustment
J = Wire Connector for RoomThermostat
K = Connector forTotal Check System
L = Selector for Local/Remote Control
M = Anti-cycling Device Adjustment for Heating
N = Soft-light Adjustment
O = Max Heating Temperature Adjustment
P = Time Clock Connection
Q = On/Off L.E.D.
R = On/Off Switch
S = Interface Wire for P.C.B.s
T = Relay Motorised Valve
U = Ignitor Relay
V = Gas Valve Relay
W = Fan Relay
X = Circulation Pump Relay
Y = Selector TCS2
Z = Link for Continuous Pump Run
A01 = Air Pressure Switch
A02 = Fan
A03 = Gas Valve
A05 = Motorised Valve
A06 = Circulation Pump
A07 = Flame Detector
A08 = Earth Terminal
B01 = Over Heat Thermostat
B02 = External Thermostat
B03 = Gas Valve Modulator
B04 = D.H.W. Probe Sensor Cylinder
B05 = Heating Sensor
B06 = Pressure Switch for Heating Circuit
B07 = Minimum pressure switch
Colours
Gry = Grey
Rd = Red
Bl = Blue
Grn/Yll = Yellow/Green
Wh = White
Brn = Brown
Blk = Black
Wh/Rd = White/Red
400
SE003A

14 400
1
2
3
4
5
6
17
18
7
8
9
10
22 21 20
19
11 13 14 15 1612
2.12 Water Circuit Diagram
Legend:
1. Air Pressure Switch
2. Fan
3. Main Heat Exchanger
4. Ignition Electrodes and Detection Electrodes
5. Burner
6. Gas Valve
8. Spark Generator
7. Automatic air release valve
8. Circulation Pump
9. Motorised Valve with by-pass
10. Main Circuit Flow Switch
11. Safety Valve (3 bar)
12. Low pressure switch
13. C.H. expansion Vessel
14. D.H.W. expansion Vessel
15. D.H.W.Storage with insulation shell
16. D.H.W. Probe
17. Expansion relief valve (6 bar)
18. Temperature/Pressure relief valve (7bar)
19. Magnesium anode
20. C.H.W. Probe
21. Overheat Thermostat
22. Drain point
SI003A

15
400
3. COMMISSIONING
3.1 Initial Preparation
MTS (GB) Limited support the initiative. Within the information pack you will find
a copy of the logbook. It is important that this is completed in the presence of
your customer, they are shown how to us it, and it is signed by them. Please instruct your
customer that they must have their logbook with them whenever they contact a
service engineer or us.
Preliminary electrical system checks to ensure electrical safety must be carried out by a
competent person i.e.polarity, earth continuity, resistance to earth and short circuit.
Filling the Heating System:
Remove the panels of the case and lower the control panel (see point 3.2.for further information).
Open the central heating flow and return cocks supplied with the connection kit.
Unscrew the cap on the automatic air release valve one full turn and leave open permanently.
Close all air release valves on the central heating system.
Gradually open valve(s) at the filling point (filling-loop) connection to the central heating
system until water is heard to flow, do not open fully.
Open each air release tap starting with the lower point and close it only when clear water,
free of air, is visible.
Purge the air from the pump by unscrewing anticlockwise the pump plug and also man-
ually rotate the pump shaft in the direction indicated by the pump label to ensure the
pump is free.
Close the pump plug.
Continue filling the system until at least 1.5 bar registers on the pressure gauge.
Inspect the system for water soundness and remedy any leaks discovered.
Filling of the D.H.W. System:
Close all hot water draw-off taps.
Open the cold water inlet cock supplied with the connection kit.
Open slowly each draw-off tap and close it only when clear water, free of bubbles, is visible
Gas Supply:
Inspect the entire installation including the gas meter, test for soundness and purge, all as
described in BS 6891:1988.
Open the gas cock (supplied with the connection kit) to the appliance and check the gas
connector on the appliance for leaks.
When the installation and filling are completed turn on the central heating system (sect.
3.4) and run it until the temperature has reached the boiler operating temperature. The
system must then be immediately flushed through.
The flushing procedure must be in line with BS 7593:1992 Code of practice for treatment
of water in domestic hot water central heating systems.
During this operation, we highly recommend the use of a central heating flushing deter-
gent (Fernox Superfloc or equivalent), whose function is to dissolve any foreign matter
that may be in the system.
Substances different from these could create serious problems to the pump or
other components.
The use of an inhibitor in system such as Fernox MB-1 or equivalent is strongly recom-
mended to prevent corrosion (sludge) damaging the boiler and system.
Failure to carry out this procedure may invalidate the appliance warranty.
3.2 Removing the Casing
VR006Aa
VR006Ab
VR006Ac

16 400
The boiler was designed to make regulation easy. To
access the adjustment and control area, simply remove the
cover by unscrewing the screws “A”and “C”and lift up the
small service panels “B1”and “B2”respectively.
The first provides access to the control (low voltage)
P.C.B., while the second makes it possible to work on the
power supply P.C.B.The service panel “B2”also provides
access to:
- the power supply cord connector;
- the fuses;
- the selector knob for continuous operation of the circulation
pump.
The service panel “B1”also provides access to:
- the potentiometer for regulating the ignition delay (anti-
cycling) feature, which can be set from 0 to 2 minutes (factory
set at 1 minute);
- the potentiometer for regulating the soft-light feature, the set-
3.4 Initial Start-up The checks to be run before initial start-up are as follows:
1. Make sure that:
-the screw on the automatic air valve has been loosened when the system is full;
- If the water pressure in the system is below 1.5 bar, bring it up to the appropriate
level;
-Check to see whether the gas cock is closed;
-Make sure that the electrical connection has been made properly and that the
earth wire is connected to an efficient earthing system;
- Supply power to the boiler by pressing the On/Off switch <L> - the L.E.D. “I”will
turn on - turn the selector knob “C”to the <winter> setting.This will start the cir-
culation pump. After 7 seconds, the boiler will signal a shut- down due to failure
ignition. Leave the boiler as it is until all of the air has been bled from the lines.
-Loosen the cap on the head of the pump to eliminate any air pockets;
-Repeat the procedure for bleeding the radiators of air;
-Open the taps for a brief period;
-Check the system pressure and, if it has dropped, open the filling loop again to
bring the pressure back up to 1.5 bar.
2. Check the exhaust flue for the fumes produced by combustion.
3. Make sure that all gate valves are open;
4. Turn on the gas cock and check the seals on the connections, including the one
for the burner, making sure that the meter does not signal the passage of gas. Check
the connections with a soap solution and eliminate any leaks.
5. Press the reset button “A”for the lighting system; the spark will light the main
burner. If the burner does not light the first time, repeat the procedure.
6. Check the minimum and maximum pressure values for the gas going to the burn-
er; adjust it if needed using the values indicated in the table in section 4. (See sect of
the servicing manual).
3.5 Operational
Adjustments
3.3 Control Panel
Legend:
AIgnition Faliure Reset/Safety Thermostat
Reset
BL.E.D. for Ignition Faliure
CSelector Knob for Summer/Winter/
Flue Test Modes
DL.E.D. for Insufficient System Pressure
EDomestic Hot Water Temperature Control
FCentral Heating Temperature
Indicating Leds
GL.E.D. for SafetyThermostat (overheating)
HHeating Temperature Adjustment Knob
IL.E.D. for ON/OFF Switch
LON/OFF Switch
OHeating System Pressure Gauge
* Warning the flue analysis mode must only be selected by a qualified service engineer.
FR004A
FO005A

The boiler is equipped with the following safety systems (see section 3.3 for refer-
ences):
1. - Ignition Failure
This control signals an ignition failure on the burner 7 seconds after a lighting failure.
The L.E.D.“B”will turn on to signal the shutdown status.
The system can be reset by pressing and releasing the button “A”after checking to
make sure that the gas valve is open.Repeat this process until the burner lights.
2. - Circulation Failure
This control signals that the safety pressure switch on the primary circuit has not
sensed a pressure of at least 1.5 bar within 40 seconds of the activation of the circu-
lation pump, it shuts off the boiler and lights the L.E.D. “D”The system can be reset
(after the pressure has been brought up to the proper level) by using the On/Off
switch “L”.
3. - Overheating
This control shuts off the boiler in the case where the primary circuit reaches a tem-
perature in excess of 110°C. The L.E.D. “G”will come on to signal this shut-off sta-
tus. After the system has been allowed to cool, the system can be reset by pressing
the button “A”.
4. - Anti-frost Device
The boiler is equipped with a device that automatically lights the main burner when
the temperature in the delivery line to the system drops below 5°C. The boiler will
continue to operate until the temperature in question reaches about 58°C.
This device is activated on a properly operating boiler if:
- the system pressure is between the acceptable values;
- the power supply to the unit is on;
- the unit is supplied with gas.
This feature is enabled also when the boiler is in summer operating mode.
5. - Safety Shut-off
At the start of every lighting phase, the P.C.B. performs a series of internal controls.
If a malfunction occurs, the boiler will shutdown until the problem has been resolved.
3.8 Boiler Safety Systems
3.6 Combustion Analysis
The boiler is designed to make it easy to analyse the combustion by-
products.
Using the especially designed apertures, readings can be taken on
the temperature of the combustion by-products and of the combustion
air, as well as of the concentrations of O2and CO2, etc.
The best maximum-power test conditions for the heating system are
when the selector “C”is turned to the flue analysis setting.
The discharge/ventilation of the exhaust fumes can be monitored to
check for losses in general pressure in the system. This is done to
eliminate the cause of lighting failure with the main burner not indi-
cated by a shutdown status.
With a differential manometer connected to the test socket on the
combustion chamber, the DP value for the air pressure switch can
be taken. The measured value should not be less than 10 mbar
under maximum thermal power conditions (with the knob “C”on the
flue test setting) in order for the unit to function properly and with-
out interruption.
3.7 Fume Discharge
Monitoring
17
400
ting for which can range from the minimum thermal power to the maximum:
- the potentiometer for the maximum thermal power for the heating system, maxi-
mum thermal power setting (factory set at the maximum value, unless indicated oth-
erwise on the adhesive sticker located in proximity to the potentiometer);
- The connection to the diagnosis device (TCS).
G20 5 mbar
G30-31 19 mbar
DC005A
FU016A

3.9 Draining the System Draining the heating system.
The heating system must be emptied as follows:
- Turn off the boiler;
- Open the drain valve for the system and place a container below to catch the water
that comes out;
- Empty the system at the lowest points (where present).If you plan on not using the
heating system for an extended period of time, it is recommended that you add
antifreeze with an ethylene glycol base to the water in the heating lines and radiators
if the ambient temperature drops below 0°C during the winter.
This makes repeated draining of the entire system unnecessary.
Draining the domestic hot water system.
Whenever there is the danger of the temperature dropping below the freezing point,
the domestic hot water system must be drained as follows:
- Turn off the general water valve for the the household plumbing system;
- Turn on all the hot and cold water taps;
- Empty the remaining water from the lowest points in the system (where present).
18 400
5. Adjust the soft-light feature;
6. Adjust the delayed lighting feature for the heating system (can be set from 0 to 2
mins.).
CATEGORY II2H3+ Methane Gas Liquid Butane Gas Liquid Propane Gas
G20 G30 G31
Recommended Soft-light Pressure
(mbar) 5-5.4 13.4 13.4
Lower Wobbe Index (15°C;1013mbar) MJ/m3h 45.67 80.58 70.69
Nominal Delivery Pressure mbar 20 30 37
Minimum Delivery Pressure mbar 17 20 25
GENUS 27 BFFI PLUS
Main Burner: n. 15 jets (ø) mm 1.25 0.72 0.72
Consumption (15°C; 1013mbar) m3/h 3.16 ---- ----
Consumption (15°C; 1013mbar) Kg/h ---- 2.35 2.32
Gas Cock Outlet Pressure
max - min mbar 11.0- 2.0 (*) - 5.0 (*) - 7.0
4. GAS ADJUSTMENTS
(1mbar = 10,197column of water)
The outlet pressure of the gas cock is obtained by completely loosening the screw on the solenoid. The maximum pressure of the gas to the
burner will be equal to the nominal delivery pressure minus the head loss within the gas valve.
CATEGORY II2H3+ Methane Gas
G20 Liquid Butane Gas G30 Liquid Propane Gas G31
4.1 Changing theType
of Gas The boiler can be converted to use either methane (natural) gas (G20) or LPG
(G30 - G31) by an Authorised Service Centre.
The operations that must be performed are the following:
1. Replace the jets on the main burner (see table in section 4);
2. Adjust the maximum and minimum thermal capacity values for the boiler (see
table in section 4);
3. Replace the gas rating plate;
4. Adjust the maximum thermal power setting;

400
It is recommended that the following checks be made on the boiler at least
once a year:
1 - Check the seals for the water connections;replacement of any faulty seals.
2 - Check the gas seals;replacement of any faulty gas seals.
3 - Visual check of the entire unit.
4 - Visual check of the combustion process and cleaning of the burners if needed.
5 - If called for by check no. 3, dismantling and cleaning of the combustion chamber.
6 - If called for by check no. 4, dismantling and cleaning of the injectors.
7 - Visual check of the primary heat exchanger:
- check for overheating in the blade assembly;
- clean the exhaust fan if needed.
8 - Adjustment of the flow rate of the gas:flow rate for lighting, partial load and full load.
9 - Check of the heating safety systems:
-safety device for maximum temperature;
-safety device for maximum pressure.
10 - Check of the gas safety systems:
-safety device for lack of gas or flame ionisation (detection electrode);
-safety device for gas cock.
11 - Check of the electrical connection (make sure it complies with the instructions
in the manual).
12 - Check of domestic hot water production efficiency (delivery rate and temperature)
13 - Check pressure in the Domestic Expansion Vessel and top up as necessary.
14 - Check manually by turning the test knob the Temperature & Pressure Relief Valve.
15 - Check manually by turning the test knob the Expansion Relief Valve.
16 - Check discharge pipes from both the central heating and domestic hot water
for obstructions.
17 - Check of the general performance of the unit.
18 - General check of the discharge/ventilation of the combustion by products.
5. MAINTENANCE
19

400
Cod. 23 99 84 1516 000
29.8/12.0
27.4/10.3
92.1
88.8
1.1
6.8
0.4
56.9
1.3
3.16
2.35/2.32
136.9
7.27
7.45
55
+5
82/42
60
40/70
18
3
0.2/6
7
1
145
3
20
30-37
230 / 50
200
X4D
2A
86
47-116-11
GENUS 27 BFFI PLUS
CE Certification
Thermal Capacity max/min kW
Thermal Power max/min kW
Efficiency of Nominal Thermal Capacity %
Efficiency at 30% of Nominal Thermal
Capacity %
Heat Loss to the Shell (∆=50°C) %
Flue Heat Loss with Burner Operating %
Flue Heat Loss with Burner Off %
Maximum Discharge of Fumes (methane) Kg/h
Residual Discharge Head mbar
Consumption at Nominal Catacity (G20-G25) m3/h
(15°C, 1013 mbar) (G30-G31) Kg/h
Temp. of exhaust fumes at nominal
capacity with methane °C
CO2 Content %
O2 Content %
CO Content ppm
Minimum Ambient Temperature °C
Heating Temperature max/min °C
Stored D.H.W. Cylinder Capacity l
Stored D.H.W. min/max Temperature max/min °C
Specific flow rate* (IN 10’∆T=30°C) l/min
D.H.W. Expansion Vessel l
Pressure of Domestic Hot Water max/min bar
Expansion Vessel Capacity l
Preload Charge bar
Maximum Water Content in System l
Maximum Heating Pressure bar
Nominal Pressure Natural Gas (G20) mbar
Liquid Gas (G30/G31) mbar
Voltage/Frequency of Power Supply V/Hz
Total Electrical Power Absorbed W
Protection Grade of Electrical System IP
Internal Fuse Rating
Weight Kg
GC Number
6. TECHNICAL INFORMATION
*BS EN 625
Manufacturer: MerloniTermoSanitari SpA - Italy
Commercial subsidiary: MTS (GB) LIMITED
MTS Building
Hughenden Avenue
High Wycombe
Bucks HP13 5FT
Telephone: [phone]
Fax: [phone]
Internet: http://www.mtsgb.ltd.uk
E-mail: [e-mail]
Technical Service Hot Line: [phone]