Ariston 47-116-17 User Manual

Installation
Instructions
Type C Boilers

G.C.N: 41-116-03

47-116-17

LEAVE THESE INSTRUCTIONS
WITH THE END-USER

Condensing

Country of destination: GB

2752275

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.

1. GENERAL INFORMATIONTABLE OF CONTENTS

1. GENERAL INFORMATION

1.1. GENERAL INFORMATION

1.3. OVERALL V

IEW

2. INSTALLATION

2.1. REFERENCE S

TANDARDS

2.2. SITING THE APPLIANCE

2.3. OVERALL DIMENSIONS

2.4. MINIMUM CLEARANCES

2.5. MOUNTING THE APPLIANCE

2.6. E

LECTRICAL CONNECTION

2.7. G

AS CONNECTION

2.8. W

ATER CONNECTIONS

2.9. FLUE CONNECTIONS

2.10. A

CCESSORY CONNECTION

2.10.1. R

OOM THERMOSTAT CONNECTION

2.10.2. REMOTE CONTROL CONNECTION

2.10.3. ACCESSORY CONNECTION TERMINAL BLOCK

2.10.4. CYLINDER TEMPERATURE PROBE CONNECTION

2.10.5. REMOTE CONTROL TERMINAL BLOCK AND
CYLINDER PROBE

2.11. E

LECTRICAL DIAGRAM

2.12. WATER CIRCUIT DIAGRAMS

3. COMMISSIONING

3.1. INITIAL PROCEDURES

3.2. REMOVING THE CASING

3.3. C

ONTROL PANEL

3.4. INITIAL START-UP

3.5. DISPLAY:MESSAGES SHOWN DURING
N

ORMAL OPERATION

3.6. OPERATING PARAMETERS

3.6.1. CONTROL MODES

3.6.2. O

UTDOOR SENSOR

3.6.3. S

ETTINGS D

ISPLAY

3.7. REGULATIONS

3.7.1. POTENTIOMETER

3.7.2. SETTING THE TEMPERATURE FIELD

3.7.3. COMFORT KEY/HEATING ONLY

3.7.4. POST-CIRCULATION OF THE PUMP

3.7.5. TEST MODE

3.7.6. R

EGULATION MENU TABLE

3.8. BOILER SAFETY SYSTEMS

3.9. COMBUSTION ANALYSIS

3.10. D

RAINING

4. GAS ADJUSTMENTS

4.1. O

VERALL VIEW

4.2. PRELIMINARIES

4.3. GAS REGULATION

4.3.1. T

EST OF THE CONNECTION PRESSURE

4.3.2. REGULATION OF THE THERMAL POWER

4.4. CHANGING THE TYPE OF GAS

4.5. O

PERATING TESTS

5. ZONE V ALVES

6. MAINTENANCE

6.1. GENERAL REMARKS

6.2. C

LEANING THE PRIMARY EXCHANGER

6.3. CLEANING THE CONDENSATE TRAP

6.4. OPERATIONAL TEST

7. TECHNICAL INFORMATION

1.1. G

ENERAL I

NFORMATION

Read the instructions and recommendations in these Installation
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 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 domestic 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 supervision.
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 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 Centre and request
the use of original spare parts. For in-guarantee repairs contact MTS
(GB) Limited

The technical information and instructions provided herein below are
intended for the installer so that the unit may be installed correctly
and safely.

The installation and initial start-up 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.

This appliance must be installed by a competent installer in
accordance with the current Gas Safety (installation & use)
Regulations.

The installation of this appliance must be in accordance with the
relevant requirements 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:

2. INSTALLATION

2.1. R

EFERENCE STANDARDS

Low pressure
pipes BS 6891 1988

Boilers of rated input
not exceeding 60 kW BS 6798 1987

Forced circulation hot
water system BS 5449 1990

Installation of gas hot water
supplies for domestic purposes
( 2

nd

family gases) BS 5546 1990

Flues BS 5440-1 1990
Air supply BS 5440-2 1989

3

275

24 MFFI

LEGEND:

1. Flue connector

2. Heating flow temperature probe

3. Mixer

4. Condensate collector

5. Expansion vessel

6. Condensate trap (tube)

7. Condensate trap

8. Diverter valve

9. Main circuit flow switch

10. Domestic hot water temperature probe

11. Control panel

12. Gas valve

13. Domestic hot water flow switch

14. Drain valve

15. Safety valve (3 bar)

16. Secondary heat exchanger

17. Circulation pump with automatic air release valve

18. Heating return temperature probe

19. Sealed combustion chamber

20. Combustion chamber inspection hatch

21. Fan

22. Ignition and detection electrode

23. Main heat exchanger (aluminium)

24. Automatic by-pass

25. Silencer

F

IG. 1.1

1.3. OVERALL VIEW

24 RFFI SYSTEM

2.3. OVERALL DIMENSIONS

FIG. 2.1

24 MFFI

24 RFFI SYSTEM

4

275

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.

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 appliance 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.

2.2. SITING THE APPLIANCE

L

EGEND:

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”)
F = Cylinder Flow (3/4”)
G = Cylinder Return (3/4”)
H = Condensate discharge

20

=

67 67

65 65

155

181

100

(A-B-D-E)

208 (C)

=

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

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 data table (1.2), 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
(see the servicing manual for further information)

FIG. 2.3

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.

5

275

In order to allow for access to the interior of the boiler for
maintenance purposes, the boiler must be installed in compliance
with the clearance requirements indicated in the diagram below.

2.4. MINIMUM CLEARANCES

FIG. 2.2

24 MFFI

24 MFFI SYSTEM

IMPORTANT!

In the event that the power supply cable 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

supplied 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
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.

6

275

2.8. WATER CONNECTIONS

L

EGEND:

A = Central Heating Flow
B = Domestic Hot Water Outlet
C = Gas Inlet
D = Domestic Cold Water Inlet)
E = Central Heating Return
F = Cylinder Flow
G = Cylinder Return
H = Condensate discharge
I = Safety valve discharge

C

ENTRAL HEATING

Detailed recommendations are given in BS 6798:1987 and BS 5449­1:1990, the following notes are given for general guidance.

P

IPE WORK:

Copper tubing to BS EN 1057:1996 is recommended for water
pipes. Jointing should be either with capillar y 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.

B

Y-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.

A

C

B

D E

I

A

C

G

D E

I

F

VIEW OF THE BOILER CONNECTIONS

FIG. 2.4

24 MFFI

24 MFFI SYSTEM

H

H

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 and manufactured in accordance with BS
2870:1980.

S

AFETY 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.

C

ONDENSATE DISCHARGE:

The condensate discharge hose from the boiler must be inserted
by at least 50 mm into a suitable acid resistant pipe - e.g. plastic
waste 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 a suitable position:

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.

ii) Connecting into the waste system of the building such as a

washing machine or sink.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.

N

OTE: 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.

A

IR 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

FIG. 2.5

Fitting the connection kit to
the ecoGENUS 24 RFFI
SYSTEM only.

It will be noted that the kit has
two connections not required
for this boiler i.e. the domestic
cold inlet “D” and the domestic
hot water outlet “B” (see fig.

2.4).
Although the cold water main supply must be connected to the
isolation valve for the purpose of operating the filling-loop, the
isolation valve is NOT connected to the boiler and should be left
in the OFF position.
The D.H.W. outlet is capped-off on the boiler, therefore not
requiring the isolation valve to be used.
The ecoGENUS 24 RFFI SYSTEM has 2 x 3/4" B.S.P. male
threads for the cylinder flow and return. It is recommended that 2
x 22mm x 3/4" female iron fittings (not supplied) be used on these
connections (using P.T.F.E. tape), before the boiler is mounted on
the wall.

7

275

In F

IG. 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.

Coaxial

Systems

Twin Pipe

Systems

Exhaust Type

C

13

B

33

outlet of fumes in

chimney or exhaust flue

C13, C33, C

43

C

53,C83

B

23

Maximum Extension

Exhaust/Air

(m)

4

4

31 (S1=S2)

55 (S1+S2)

54 (S2)

Diameter

of Pipes

(mm)

Ø 60/100

Ø 60/100

Ø 80/80

Ø 80/80

Ø 80

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

FIG. 2.6

2.9. FLUE CONNECTIONS

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.
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 appliance
model number.

A suitable terminal guard is available from:

TOWER FLUE COMPONENTS
Morley Road
Tonbridge
Kent TN9 1RA

R

ESIDUAL HEAD OF THE BOILER

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.

F

ILLING:

A temporary method for initially filling the system and replacing
lost water during servicing and initial filling (in accordance with
Water Supply Byelaw 14), is provided as an integral part of the
connection kit (see F

IG. 2.5). The flexible hose must be removed

once the system has been filled. The D.H.W. inlet valve on the
connection kit has two positions, 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.

D

OMESTIC W

ATER

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.

The minimum acceptable spacing from the terminal to obstructions
and ventilation openings are specified in Fig.2.6

8

275

FIG

. 2.11

2.10. ACCESSORY CONNECTION

To carry out the connection for the roomstat or the outdoor sensor,
proceed as follows:

1. Unscrew the screws “A” and rotate the control panel forwards;

2. Insert the connection cable for the thermostat or the outdoor

sensor into the cable gland “B” and open the lid of the control
panel after having first unscrewed fastening screws “C”.

3. Insert the connecting cable into the cable clamp “D” shown in
the figure and fasten it.

4. Remove the grommet “E” shown in the figure, make a hole in it
and pass the connecting cable for the roomstat or the outdoor
sensor through it.

5a. In order to connect up the roomstat, remove the link that is

located in the “F” terminal (marked with the initials “TA”) and
connect the cables.

5b. To connect up the outdoor sensor, insert the cables into the “G”

clamp (marked with the initials “SE”).

6. Return the grommet “E” to its initial position, then close back
the lid and lastly return the control panel to its place.

7 If a remote time clock is to be fitted, disconnect the integral time

clock plug from the P.C.B.

8 Using a volt-free switching time clock, connect the switching

wires from the time clock following points 1-6 above.

9 If 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.

For details on fitting the D.H.W. probe (ecoGENUS 27
RFFI only), please consult the separate instruction
sheet supplied with the probe.
An anti-frost device is built-in to the appliance’s
electronic regulation system.

1

2.10.1. ROOM THERMOSTAT CONNECTION

2

3

4

B

D

A

C

E

F

G

E

9

275

Refer to the illustrations in section 2.10.1.

1. Unscrew the screws “A” and rotate the control panel forwards.

2. Insert the connecting cable of the under floor heating sensor into

the cable gland “B” and open the lid of the instrument panel
after having unscrewed the fastening screws “C”.

3. Remove a blind grommet, make a hole in it and insert the
connecting cable of the under floor heating sensor through it.

4. Remove the jumper located in the flying clamp

5. Connect the cables of the under floor heating sensor to the flying

clamp connected to position C6 on the P.C.B. (in place of the
position previously occupied by the jumper).

6. Bring the grommet back to its initial position, close the lid and
lastly the control panel.

2.10.4. UNDER FLOOR HEATING CONNECTION

2.10.5. REMOTE CONTROL TERMINAL BLOCK,

CYLINDER PROBE AND SECONDARY OUTLET

C5 (1-2)
(red)

C6 (3-11)
(grey)

C7 (1-9)
(violet)

CONNECTIONS TO THE P.CB.

JUMPER:
UNDER FLOOR
HEATING
SENSOR

REMOTE CONTROL

SECONDAR Y OUTLET
(LPG valve,
secondary pump)

2.10.3. ACCESSORY CONNECTION TERMINAL BLOCK

2.10.2. REMOTE

CONTROL CONNECTION

Refer to the illustrations in section 2.10.1.

1. Unscrew the screws “A” and rotate the control panel forwards.

2. Insert the connecting cables of the remote control into the cable

gland “B” and open the lid of the control panel after having
unscrewed the fastening screws “C”.

3. Remove a blind grommet, make a hole in it and pass the
connecting cable of the remote control through it.

4. Connect the cables of the remote control to the flying lead (see
section 2.11.) connected to position C5 on the P.C.B. (positions
with no closed jumper).

5. Bring the grommet back to its initial position, then close the lid
and lastly the control panel.

N

OTE

: The wir ing of the RC must be done by using 2 x 0.5 mm

2

cable
this guarantees a maximum length of 500 m.
The “BUS” cable of the RC must be wired separately from the 230
VAC cable.

NOTE: The wiring of the Outdoor Sensor (SE) must be done by using

2 x 0.5 mm

2

cable this guarantees a maximum length of 50 m.
The sensor must be positioned at least 2 - 2.5 m above the
ground and where possible facing north.The sensor must not
be exposed to direct sunlight.

LEGEND

:

A: JUMPER

When needed, the P.C.B. allows the different options to be selected
by means of a wire link.
The boiler has the following basic arrangement:

1 OPEN
2 CLOSED (jumper)
3 OPEN
4 OPEN
5 OPEN
6 OPEN
7 CLOSED
8 OPEN (MFFI); CLOSED (SYSTEM)

N

OTE

: under absolutely no circumstances must jumpers 2, 7 and 8

be removed. The opening of such contacts will lead to boiler
malfunction.

This is the factory configuration. It is recommended that this set-up
not be changed, unless under the following particular circumstances:
JUMPER 3: if the contact is closed, the Secondary Output (flying

clamp connected to connection C7; positions 1-9)
controls an LPG valve (optional).

JUMPER 4: if the contact is closed, the continuous operation of

the pump is selected. If the contact remains open, it
has no effect and there is no change in the
operation of the boiler.

JUMPER 5: if the contact is closed, the signal transmitted by the

connection of the secondary output clasp
(connected to C7; positions 1-9) relates to a
secondary pump (optional). If the contact remains
open, the output signal controls a zone valve

(optional).
JUMPER 6: not used
JUMPER 7/8:

I = inserted (contact closed)
N.I = not inserted (contact open)

N

OTE: it is essential that the operations involving setting of the

jumpers be carried out only with the device turned off.

10

275

The P.C.B. is fitted with 2 fuses, on the
live and the neutral.
The fuse holder contains:

- 5 x 20mm “3.15A Slow”glass fuses

2.11. ELECTRICAL DIAGRAM

B: Control microprocessor
C: Flame detection jumper (under no circumstances should this

jumper be moved from the 1-2 position)
D: Anti-cycling device (RA)
E: Maximum heating output regulation (PR)
F: Soft-light regulation (RLA)
G: Operating mode selector knob
H: Heating temperature adjustment
I: Domestic hot water temperature adjustment
J: Remote control module
K: Main microprocessor
L: Relay
M: Fuses (2 x 0.54 A SLOW)
N: Transformer (PRI: 230V-50Hz; SEK: 10V-0,8VA; SEK:10V-3,5VA;

SEK:10V-3,5VA;)
O: Fuses (2 x 3.15 A SLOW)
P: Earth
Q: Spark generator
R: Connection to the main P.C.B.
S: Comfort light
T: Programming keys
U: Comfort key
V: Alpha-numeric display
X: Set and reset key
W: Connection to PC

C1 = FAN

1: “Hall” sensor power supply 12V (red)
2: “Hall” sensor ground (blue)
3: Not used
4: Start of coil (black)
5: “Hall” sensor input (white)
6: End of coil (brown)

C2 = POWER SUPPLY

1: Earth (yellow/green)
2: Earth (yellow/green)
3: Not connected
4: Neutral (blue)
5: Not connected
6: Live (brown)

7

N.I.

I.

N.I.

I.

8

N.I.
N.I.

I.
I.

CONFIGURATION

Central heating only
MFFI
Not used
RFFI System

11

275

2.12. WATER CIRCUIT DIAGRAMS

LEGEND:

1- Fan
2 - Main Heat exchanger
3 - Ignition/detection electrode
4 - Burner
5 - Gas valve
6 - Heating return temperature probe
7 - Heating flow temperature probe
8 - Silencer
9 - Motorised valve
10 - Automatic by-pass
11 - Main circuit flow switch
12 - Domestic hot water temperature probe
13 - Secondary heat exchanger
14 - Domestic hot water inlet filter
16 - Drain valve
17 - Safety valve
18 - Pressure gauge
19 - Circulation pump with automatic air release valve
20 - Expansion vessel
21 - Condensate trap inspection cap
22 - Condensate trap
23 - Condensate discharge tube
24 - Condensate trap inlet
25 - Injector
26 - Domestic hot water flow switch

24 MFFI

C3 = CONNECTION TO ROOMSTAT

1: Input - 1
2: Input - 2

C4 = TIMER

1: 3 V output
2: Timer ground
3: Timer output
4: Not connected

C5 = REMOTE CONTROL (Bus+/Bus-)

1: Input/output-1
2: Input/output-2

C6 = SENSOR CONNECTOR

1: Domestic hot water flow switch (grey)
2: Main circuit flow switch (grey)
3: Under floor heating thermostat (grey)
4: Heating flow sensor (grey)
5: Heating return sensor (grey)
6: Domestic hot water sensor (grey)
7: Not used: jumper
8: Outdoor sensor (grey)
9: Domestic hot water flow switch (grey)
10: Main circuit flow switch (grey)
11: Under floor heating thermostat (grey)
12: Flow sensor (grey)
13: Heating sensor (grey)
14: Domestic hot water sensor (grey)
15: Not used: under floor heating
16: Outdoor sensor (grey)

C7 = EQUIPMENT CONNECTIONS

1: Secondary output (optional)
2: Gas valve (white)
3: 3-way valve neutral (white)
4: Pump (white)
5: Ionisation (black)
6: Not connected
7: Ground
8: Pump earth (yellow/green)
9: Secondary output (optional)
10: Gas valve (brown)
11: 3-way valve (domestic hot water) (brown)
12: 3-way valve (heating) (brown)
13: Pump (brown)
14: Not connected
15: Earth
16: Gas valve earth (yellow/green)

12

275

3. COMMISSIONING

3.1. INITIAL PREP ARATION

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.

F

ILLING THE HEATING SYSTEM:

Remove the panels of the case and lower the control panel (see
section 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 the pump plug
and also manually 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 bar registers on the
pressure gauge.
Inspect the system for water soundness and remedy any leaks
discovered.

F

ILLING 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

G

AS 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 r un 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 detergent (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 the system such as Fernox MB-1 or
equivalent is strongly recommended to prevent corrosion (sludge)
damaging the boiler and system.

Failure to carry out this procedure may invalidate the appliance
warranty.

24 RFFI SYSTEM

LEGEND

:

1- Fan
2 - Main Heat exchanger
3 - Ignition/detection electrode
4 - Burner
5 - Gas valve
6 - Heating return temperature probe
7 - Heating flow temperature probe
8 - Silencer
9 - Motorised valve
10 - Automatic by-pass
11 - Main circuit flow switch
12 - Non-return valve (integral to Jig Kit)
13 - Filling loop (integral to Jig Kit)
14 - Indirect cylinder expansion vessel
15 - Expansion relief valve
16 - Drain valve
17 - Safety valve (3 bar)
18 - Pressure gauge
19 - Circulation pump with automatic air release valve
20 - Expansion vessel
21 - Condensate trap inspection cap
22 - Condensate trap
23 - Condensate discharge tube
24 - Condensate trap inlet
25 - Injector

3.3. CONTROL PANEL

A. Selector Knob for Summer/Winter/Flue Test Modes
B. Domestic Hot Water Temperature Adjustment Knob
C. Central Heating Temperature Adjustment Knob
D. On/Off L.E.D.
E. On/Off Knob
F. “COMFORT” Function Push-button/heating only (RFFI SYSTEM)
G. “COMFORT” Function L.E.D./heating only (RFFI SYSTEM)
H. Reset Button
I. Multifunction Display
J. Heating System Pressure Gauge
K. Time Clock
L. Programming “+”key
M. Programming “-” key

When necessary configure the main P.C.B.according to the following
diagram (please refer to the legend on page 17)

I = inserted (contact closed)
N.I = not inserted (contact open)

SECONDARY OUTLET = conntection C7 (position 1-9 page 17)

1. Make sure that:

- the cap of the automatic air release valve is loosened;

- the system pressure is at least 1 bar on the pressure gauge;

3.4. INITIAL START-UP

3.2. REMOVING THE CASING

To disassemble the front casing panel, follow these steps:

1. Unscrew the screws “A” (1/4 turn only) and rotate the control
panel forwards;

2. Unscrew the screws “B”;

3. Unhook the front panel of the casing by lifting it.

To disassemble the side panels, follow these steps:

4. Unscrew the screws “C” (at bottom) fastening the side panels;

5. Lift and unhook the panels.

13

275

A

1

B

2

3

C

4 5

POSITION

3

4

5

INSERTED

Secondary outlet (connection
C7; positions 1-9) controls a
LPG valve (optional).

Continuous pump operation.

Secondary output relates to a
secondary pump (optional).

NOT INSERTED

The secondary outlet
controls what is
selected by Jumper 5.

No change in pump
operation.

Secondary output
controls a zone valve
(optional)

7

N.I.

I.

N.I.

I.

8

N.I.
N.I.

I.
I.

CONFIGURATION

Central heating only
MFFI
Not used
RFFI System

14

275

3.5. DISPLAY:MESSAGES SHOWN DURING

N

ORMAL OPERATION

3.6. OPERATING PARAMETERS

3.6.1. CONTROL

MODES

During operation of the boiler, while it is carrying out its normal
operations, the left-hand display shows a series of characters that
refer to the operations indicated below:

--

Diagnostics phase (precedes the other operations)

00

No request for heat

CC

Heating, burner off

CC..

Heating, burner on

cc

Pump overrun for heating

dd

Domestic hot water, burner off

dd..

Domestic hot water, burner on

hh

Pump overrun for domestic hot water

bb

Storage cylinder, burner off (SYSTEM version)

bb..

Storage cylinder, burner on (SYSTEM version)

N

OTE: the flashing dot on the left-hand display always indicates

“burner off”; if the still dot indicates “burner on”.
The right-hand display (two-digit) shows:

- in HEATING mode: temperature of the heating system flow;

- in DOMESTIC HOT WA TER mode:temperature of domestic hot water.

The boiler has been designed to allow easy intervention with regard
to the operating parameters.

The generation of the set-point and the request for heat are clarified
in the following diagram, with regard to the heating mode.

* See section 3.6.2.
The remote control and the timer are available as an accessory Kit:
in the preceding diagram, it is clear that in the event that a device of
this type is not installed, the calculation of the set-point depends on
an outdoor sensor (if installed) and is carried out by the P.C.B.

N

OTE

: a configuration is also possible which allows for the

simultaneous presence of a remote control and an outdoor sensor.In
this case, the flow temperature is calculated as a function of the
external temperature and the room temperature. In this manner, it is
possible to carry out a particularly efficient modulation, which allows
considerable comfort to be obtained, combined with savings in fuel.
The influence of the roomstat and the timer are shown in the
following diagram, taking into consideration the fact that:

- ON/OFF Room ther mostat installed: contact open or closed,
controlled by the room thermostat temperature sensor.

- ON/OFF Room thermostat not installed: contact closed (jumper).

- Timer installed: contact open or closed, controlled by the timer
settings entered by the user.

- Timer not installed: contact open.

LEFT RIGHT

- the gas cock is closed;

- the electrical connection has been carr ied out in the correct
manner. To allow the air to escape from the system, proceed as
follows:

- turn on the On/off knob “D” and position the selector knob “A” in
the “winter” position. The boiler pump will start up and three
consecutive attempts will be made to ignite the burner. After the
third attempt, the electronic system will shutdown the boiler,
because the supply of gas has been cut off. The message “A01”
will appear on the display;

- let the pump operate until all the air has escaped from the
system;

- repeat the procedure for bleeding the radiators of air;

- draw hot water for a short while;

- check the system pressure and, if it has gone down, fill it with
water until it returns to 1 bar.

2. Check the flue system for products of combustion.

3. Check that any required local ventilation inlets are open.

4. Fill the boiler condensate trap with water.
N.B. In the event of prolonged period of system shutdown,
the condensate trap should be filled before any renewed use.
A shortage of water in the trap is dangerous because it could
possibly lead to a leakage of fumes into the air.

5. 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.

6. Press the reset button “H” for the lighting system; the spark will
light the main burner. If the burner does not light the first time,
repeat the procedure.

The boiler is configured in the factory for the gas type in
question. It is not necessary to regulate the gas type on
installation.
N

OTE: the reference values of the CO

2

are contained in the

T

ECHNICAL INFORMATION

section on page 4.

Schematic representation of the influence exerted by the roomstat
and by the timer on the request for heat and on the calculation of the
set-point (flow temperature of the primary circuit) by means of the
external temperature values:

The type of curve is entered by means of the controls of the display
P.C.B located under the lid of the P.C.B. itself. To access the
programming buttons (+ / -), raise the lid with a screwdriver as shown
in the illustration.

In the event of the chosen curve not being the most suitable for the
type of system, it may be changed (selecting a more appropriate
one) or moved until the desired thermal behaviour is obtained for the
boiler and the system.

15

275

3.6.2. OUTDOOR SENSOR

In the case of the use of an outdoor sensor, the microprocessor­controlled P.C.B. calculates the most suitable flow temperature,
taking into account the external temperature and the type of system.
The microprocessor is capable of doing this because it is possible to
establish a link between the external temperature and the flow
temperature of the heating system water. This link translates into a
"thermal curve".
The type of curve should be chosen in correspondence with the
planned temperature of the system and the nature of the heat loss
present in the building.
The flow temperature directly influences the room temperature,
therefore making reference to the room temperature is equivalent to
indicating variations in the temperature of the building.

-

+

PROCEDURES AND PRACTICAL EXAMPLES

:
If the building is always cold, under all external temperature
conditions (and therefore in all seasons), the steps to take are as
follows:
The curve must be translated parallel to itself, i.e. raising the flow
temperature (and thereby the room temperature) in parity with the
external temperature.

It is possible to carry out this operation by heating temperature knob.
The konb in vertical position set a temperature oh 20°C.Turning the
knob on the right it’s possible to set a higher room temperature.

In this manner, temperatures for the water coming out of the boiler
are set successively higher, which then influence the room
temperature increasing it to the desired settings.

While turning the knob the display shows “d.xx” for few seconds, “xx”
is the room temperature set. Alternatively, it is possible to lower the
output temperature of the boiler if the room temperature is too hot.
It is possible obtain this turning the knob on the left translating lower
the curve.

NB: The last effect achieved by adjusting the thermal curves is to change

the behaviour of the system in relation to the room temperature. If
the curve used has been selected underestimating the thermal
needs of the building, i.e.it is too “low”, it is possible that the building
will not heat up sufficiently (the boiler will arrive to the set-point
before the building reaches the desired temperature); the result is
that the building will feel cold.

100

60

789

6

5

4

3

2

1

20

+20

-20

16

275

The general conditions to follow upon installation are the following:
Warning (see 3.7.2)
* The curves 1,2,3,4,5,6 could be set in the lower temperature;
* The curves 5,6,7,8,9 could be set in the upper temperature;

CURVE 1: under floor heating (radiant panels at ultra-low

temperature).Planned temperature 30/20°C.

CURVE 2-3: under floor heating (radiant panels, low temperature

radiant plate systems).Planned temperature 40/30°C.

If the room temperature is too cold during the
winter (while in spring the temperature is
adequate), it is necessary to enter a steeper
curve. To do this, press the reset button for 5
seconds and then press it repeatedly until the

letter “FF” appears (using the “+” and “-” keys).
In this manner, the curves may be selected
from 1 to 5.

Alternatively, if the building is too warm in the
winter, while the room temperature is
adequate in warmer seasons, it is necessary
to choose a less steep curve, adjusting it in
the same manner as above.

For buildings with standard insulation, materials and exposure, it is recommended initially that the straight line not be moved parallel to itself. If
a timer is installed, it is possible to set different temperatures for daytime and night-time. It is therefore possible to lower the temperature that
the P.C.B. calculates in relation to the values provided by the outdoor sensor by a quantity decided by the user for night-time operation.To do

this, it is necessary to select the night function “uu”, in the following manner:

- press the reset key for 5 seconds;

- press the same key again once to make the “nn” character appear;

- using the programming keys “+” and “-”, select a value from 0 to 12 depending on the amount of night-time lowering of the temperature
desired.

CURVE 4-5: conventional low temperature boilers (cast iron and

aluminum radiators, radiant plate systems). Planned
temperature 60/45°C.

CURVE 6-7: conventional low temperature boilers (cast iron and

aluminum radiators, radiant plate systems). Planned
temperature 75/60°C.

CURVE 8-9: boilers with higher temperatures (radiators, convectors,

fan coils).Planned temperature 90/75°C.

In the opposite situation (in which the building is too hot in spring and
adequately heated in winter), a higher curve (“dd” and “+”) must first
be chosen and then “moved”turning the heating temperature knob.

If the following situation occurs: with low external temperatures (e.g:
winter, -20°C) the building is adequately heated, but with favourable
climatic conditions (e.g: spring, +20°C) it is not sufficiently heated, it is

necessary first to choose a lower curve (“FF” on the display and then “-”)
and then turning the heating temperature knob.

17

275

3.7.2. SETTING THE TEMPERATURE FIELD

Remove the protection of the display using a screwdriver as a lever.
Press the reset button for over 5 seconds. The display will show

“

AA0033

”. On pressing the reset button again the display will change to

“

RR0000

” (R indicates the setting of the field of regulation of the flow
temperature). Using the button “E”, the setting may be changed. It is
possible to choose two fields of regulation of the flow temperature.

“

0000

” signifies that the flow temperature (which may be set by means
of the knob on the front control panel) may be regulated from 30 to
75°C. “

0011

” signifies that the flow temperature (which also may be set
by means of the knob on the front control panel) may be regulated
from 42 to 82 °C.The factory setting is “

0000

”.

The boiler allows the convenience level to be increased in the output
of domestic hot water by means of the “COMFORT” function. This
function keeps the secondary exchanger warm during the periods in
which the boiler is inactive, thereby allowing the initial water drawn to
be at a higher temperature. The function may be activated by
pressing the “H” key on the control panel (see section 3.3.). When
the function is active, a green light comes on, again located on the
control panel.

N

OTE: During the overrun period of the pump, the “COMFORT”

function, if selected, is temporarily deactivated. The L.E.D. light
remains on to indicate that the boiler will return to the “COMFORT”
mode once the pump overrun is terminated.

This function may be activated by pressing the “H” key on the
control panel (see section 3.3.). When the function is active, a green
light comes on, again located on the control panel.This indicates that
the external indirect cylinder is not maintained at the set temperature,
only the anti-frost protection of the indirect cylinder is active. When
the temperature goes below 5°C, the boiler turns itself on and heats
up the indirect cylinder until the temperature goes over 10°C.

H

EATING ONLY KEY:

24 RFFI

3.7. REGULATIONS

To access the areas reserved for the regulation and control, open the
control panel, after having first unscrewed the plastic fastening
screws, and raise the rubber protection stopper for the
potentiometers, as shown in the illustration.

This allows access to the three regulation potentiometers:

1. RA - Ignition delay (anti-cycling device) potentiometer

It is possible to set the ignition delay by adjusting the
potentiometer with a screwdriver. The values that may be
selected range from 0 to 15 min.
The delay has been set at 15 minutes in the factory. The value

D

ISPLAY MESSAGE REFERENCE

3.7.1. P

OTENTIOMETERS

The boiler is designed to monitor some operating variables and
settings by means of the display on the front control panel. Keeping
the reset key pressed for over 10 seconds allows access to the
“readout” function of the main system variables. By pressing the
button repeatedly after that, it is possible to read the following
information in sequence:

Indication on the
left-hand display

UU//11

UU//22

UU//55

UU//FF

UU//tt

PP//AA

PP//--

PP//LL

bb

ll

Value read on right-hand display

Flow temperature of the heating circuit (C°)
Return temperature of the heating circuit (C°)
Domestic hot water output temperature (C°)
Ionisation current (expressed in bT)
Main circuit flow switch
Heating ignition delay (see section 3.6.4. ­expressed in min.x10)
Maximum thermal power for heating (expressed
in a percentage of the difference between the
maximum power allowed by the boiler and the
minimum)
Soft light power (expressed in a percentage of
the difference between the maximum power
allowed by the boiler and the minimum)
Last safety shut-off (see section 3.7.)
Last shutdown (see section 3.7.)

3.6.3. SETTINGS DISPLAY

To return to the normal display, press the “H” reset key repeatedly
until all the sequence of “readout” functions have scrolled through the
display and until one of the “display of normal operations” has
appeared (the message that appears will depend on the current
operating mode of the boiler).

* N

OTE 1: U/1 means that “

uu

”and “11” blink alternately on the display

N

OTE 2: the value 100% appears as “

0000

” on the display

entered may be viewed in the manner described in section 3.6.3.
(the display shows the value with steps of 10).

2. PR - Maximum heating circuit power potentiometer, variable

between the maximum allowed by the boiler and the minimum
(see “T

ECHNICAL INFORMATION” table). The boiler is calibrated in

the factory at 70%.

3. RLA - Soft-light potentiometer, variable between the

maximum power (shown on the display as “

0000

”, i.e. 100%) and

minimum power (shown on the display as “

0011

”, i.e.1%).The boiler
is calibrated in the factory at a value which is suitable for ignition
with any type of gas (approx.70%).
The display shows the value between 100% (“

0000

” on the display)

and 1% (“

0011

”) of this interval. The indications on the display with

regard to the power are shown in the graph:

3.7.3. COMFORT KEY:

24 MFFI

The pump overrun may be varied (after the burner has been tur ned
off). To access this function, it is necessary to press the reset button
for over 5 seconds and then press it repeatedly until the character

“AA”appears on the left-hand display.
The following modes are available:

0011

1 minute of pump overrun

0033

3 minutes of pump overrun

0066

6 minutes of pump overrun

0099

9 minutes of pump overrun

1122

12 minutes of pump overrun

1155

15 minutes of pump overrun

CCOO

24 hours of pump overrun

It is also possible to set a continuous pump operation by closing the
contact of jumper 4 (see section 2.12.).

Safety shutdown:In the event that a safety shutdown occurs, it is
necessary to contact an Authorised Service Centre.

DISPLAY

AA0011

AA0022

AA0033

AA0077

AA1199

AA2200

AA2211

AA2222

AA3333

AA9999

CAUSE

Too many attempts to ignite on starting up
After three attempts at ignition, no increase in DT was
detected
The heating flow temperature exceeds 100°C during
operation
Too many failures to flame in one period during operation
The flame was detected after the gas valve had closed
The flame was detected before the gas valve opened
The flow switch does not close
The flow switch does not open
Problem with the fan
Problem with the electronic monitoring

NOTE: When there is no ignition, check that the gas cock is open.

18

275

3.7.4. PUMP OVERRUN

3.8. BOILER SAFETY SYSTEMS

3.7.6. R

EGULATION MENU TABLE

3.7.5. TEST MODE

Summary of the functions accessed when the RESET button is pushed for 5 seconds.

The boiler is protected from malfunctioning by means of internal
checks by the P.C.B., which brings the boiler to a stop if necessary.
In the event of the boiler being shut off in this manner, a code
appears on the display which refers to the type of shut-off and the
reason behind it.
There are two types of shut-off:

- SAFETY SHUTDOWN :these group of errors (characterised on
the display by the letter “EE”) this situation is automatically
removed as soon as the cause behind it is resolved.

As soon as the origin of the shutdown disappears, the boiler
starts up again and returns to its normal operation.

- SHUTDOWN: (characterised on the display by the letter “AA”), it is
not removed unless a manual intervention is made.
The boiler may return to operation only if reset by means of
pressing the button “H” (see illustration on page 18) located at
the centre of the display.

There follows a list of the shutdown modes and the respective codes
shown on the display.

Shutdown (“AA” type): if such a situation occurs, it is necessary to reset
the boiler using the appropriate key. If this shutdown occurs again, an
Authorised Service Centre should be contacted.

The P.C.B. allows the boiler to be forced to the maximum or minimum
power.
To make the boiler operate at maximum power (100%: 24kW), it is
necessary to turn the selector knob “A” (section 3.3.) and, using a
light pressure, bring it to the < > position.To return the boiler to its
normal function, turn the selector “A” to the summer or winter
position.

N

OTE: To force the boiler to its maximum output it is necessary to

completely rotate the potentiometer for maximum heating output
regulation (PR).

19

275

The draining of the heating system must be carried out as follows:

- Turn off the boiler and the bipolar switch;

- Loosen the automatic air release valve (27);

- Open the system's discharge valve (18) and gather the water
that comes out in a container;

- Empty out from the lowest points of the system (where
provided).

If the system is to be left active in areas where the room temperature
may go below 0°C during winter, it is recommended that anti-freeze
liquid be added to the water in the heating system in order to avoid
the need for repeated draining.

Draining the domestic hot water system
Every time that there is a danger of freezing, the domestic hot water
system must be drained as follows:

- close the water mains stop-cock;

- open all the hot and cold water outlets;

- empty out from the lowest points (where provided).

3.9. C

OMBUSTION ANALYSIS

3.5. D

RAINING

There follows a description of the safety functions that most influence
the behaviour of the boiler.

1. FLOW SWITCH. At the beginning of every ignition sequence, the
P.C.B. checks the operation of the main circuit flow switch.
Initially, the pump is off and the flow switch must be open (not
giving consent); if this does not occur within the space of a
minute, the system carries out a shutdown.When the flow switch
is open, the pump is turned on and within one minute the flow
switch must close; if it does not do so, the monitoring
mechanism shuts down the boiler (with the pump off).
During normal operation, the flow switch must remain closed; if it
opens for over two seconds, the boiler shuts down, then the
monitoring mechanism will attempt to turn it back on.

2. F

AN. On ignition, the fan must rotate at the correct speed,

otherwise the boiler will not attempt to turn itself on. During
operation, the fan rotates at the speed set by the control P.C.B.;
if the number of rotations deviates by more than 300 rpm from
this setting, the boiler shuts off.

3. O

VERHEATING. This device shuts down the boiler in the event that

the primary circuit reaches a temperature that exceeds 100°C.
The operation of the overheat monitoring mechanism also
includes the following precautionary measures:

- After every ignition, the system flow temperature or the
flow/return difference must increase by 3°C in 20 seconds. Until
an increase of 3°C is reached, the boiler remains at the ignition
power. If the increase in temperature does not come about, the
boiler shuts down and will not attempt to re-ignite until the flow
temperature is below 50°C. If after three attempts the
temperature does not increase, the boiler shuts down.

- Before the boiler attempts ignition, the system flow/return
temperature difference must be below 20°C. In order for a
successive attempt at ignition to be carried out, the system must
register that once every 2 hours the flow/return temperature
difference is below 5°C.

- If, during operation the return temperature becomes greater than
the flow temperature by more than 5°C, the boiler shuts down
immediately.

4. D

AILY TEST. In order to prevent the shutdown of the components,

the boiler carries out a self-diagnosing test every 24 hours: the
pump turns on for 3 seconds and the diverter valve moves.

5. A

NTI-FROST DEVICE. The boiler is fitted with an anti-frost device

consisting of three separate functions:

- Monitor ing of the system flow temperature: if this temperature
goes below 5°C, the pump turns on (heating system circulation).
If the temperature goes below 2°C, the boiler turns on at the
minimum power and remains on until the return temperature is
over 10°C.

- Outdoor sensor installed: the pump turns on if the external

DISPLAY

EE0033

EE5566

EE6666

EE0044

EE0055

EE0088

EE2200

EE2211

EE2222

EE2233

EE6644

EE7744

EE9999

CAUSE

Flow temperature over 100°C while boiler is not in
operation (stand-by)
Heating flow temperature probe in open circuit
Heating flow temperature probe short-circuited
Domestic hot water temperature probe in open circuit
Domestic hot water temperature probe in short circuit
Under floor heating temperature probe in open circuit
Flame detected with gas valve closed
Error in the electrical connection (live and neutral crossed)
Problem with the 50Hz power supply
Flame detection electrode short-circuited
Heating return temperature probe in open circuit
Heating return temperature probe in short circuit
Problem within the electronic system

temperature goes below -3°C, it turns off when the external
temperatures raises above -1°C.

- Continuous operation of the pump: select by means of jumper 4
(see paragraph 3.6.6.).

N

OTE: In all cases, the circulation takes place in the heating system.

The anti-frost device activates only when (with the boiler operating
correctly):

- the system pressure is correct;

- the boiler is electrically powered;

- there is a supply of gas.

6. A

NTI-SCALE DEVICE. When producing domestic hot water, the

burner shuts off whenever the output temperature of the hot
water exceeds 62°C or the flow temperature of the primary
circuit exceeds 72°C. It will not turn on if the temperature of the
primary circuit is greater than 72°C.

The boiler is designed to
allow for easy analysis of
the products of
combustion.
Using the special traps, it
is possible to detect the
temperature of the burnt
gas, the combustion air,
the concentrations of O

2

,

CO2, etc.
The maximum heating power test conditions may be optimised by

turning the selector knob “C” to the flue test position.

20

275

4. GAS ADJUSTMENTS

4.1. OVERALL VIEW

4.2. PRELIMINARIES

Type of appliance

Marking on the label of characteristics
Further indications

Factory setting for the Wobbe Wo index
in kWh/m3

Factory setting of the thermal capacity
for the production of hot water

Factory setting of the thermal capacity
for the heating

LL

Yellow adhesive label:

calibrated for 'L' type

methane

Wo=11.5 Kw/m3

(from 9.5 to 12.4 kWh/m)

20mbar

11.5

E

Yellow adhesive label:

calibrated for 'H' type

methane

Wo=14.1 Kw/m3

(from 11.4 to 15.2 kWh/m3)

20mbar

14.1

LPG

Yellow adhesive label:

calibrated for LPG

Wo=24.3 Kw/m3

(from 20.2 to 24.3

kWh/m3)

50mbar

24.3

Maximum thermal power

70% Maximum thermal power

Natural Gas LPG

NOTE: the values refer to the upper calorific power

Check that the indication for type of appliance (category and type of
gas calibration) reported on the label of characteristics corresponds
to the gas family / group of the gas supply.

The type of of appliance does not
correspond to the gas family of the
gas supply

The type of appliance corresponds
to the gas family of the gas supply

The type of appliance does not
correspond to the gas supply group
(but corresponds to the family).

The appliance cannot be installed or put into operation.

Check the regulation according to section 4.3
In the event of the heating power setting being different from the
thermal power setting required, the gas must be adjusted as in
section 4.3. Otherwise, it is enough to check the
correspondence.

Transform the boiler in accordance with section 4.5, after which:
Check the regulation in accordance with 4.3
Carry out the gas regulation in accordance with point 4.3 in
keeping with the thermal power requested.

Domestic hot water:
Heating:

Domestic hot water:
Heating:

A

B

C

4.3. GAS REGULATION

4.3.2. R

EGULATION OF THE THERMAL POWER

To regulate the gas, the sequence described below must be followed.

- Unscrew by 2 to 3 rotations the sealing screws marked “PE” of
the pressure measurement inlet nipple

- Connect up a pressure gauge

- Place the appliance in operation in accordance with the usage
manual

- Measure the connection pressure (dynamic pressure)

This pressure, for methane gas, must be between 18 and 25 mbar.
In the event that the pressure is outside of the above range, the
boiler must not be placed in operation.

- Turn off the boiler.

- Remove the pressure gauge.

- Screw in the sealing screws of the pressure measurement inlet
nipple and check the seal.

If it proves impossible to eliminate the defect, contact the gas supply
board.

4.3.1. INLET PRESSURE TEST

For the regulation of the gas in the ecoGENUS, two separate
operations are required.
A) Domestic hot water side (test only)
B) Heating side (regulation and test)

A) D

OMESTIC HOT WATER:

The thermal power for the hot water is set in the factory at the
maximum power.
For this reason the boiler does not need any regulation of the gas
from the "domestic hot water" side, just a test using the volumetric
method at the gas meter:

- Make sure that there are no other gas appliances in operation
during the test.

- Place the boiler in operation in accordance with the usage
manual and draw hot water (tap totally open, temperature knob
at 9).

N

OTE: the test of the volumetric rate of flow must be carried out for at

least two minutes of boiler operating time.

- Identify the volumetric rate of flow for the maximum thermal
power from the table at the end of this section.

21

275

4.4. CHANGING THE TYPE OF GAS

4.5. OPERATING TESTS

The boiler may be transformed for use with LPG (G30-G31); the
operation must be performed by an Authorised Service Centre.
The operations to carry out are the following:

1. Replacement of the nozzle (see table);

2. Replacement of the gas label;

3. Regulation of the slow ignition (refer to section 3.7 and the table
in 4.3)

- Place the boiler in operation in accordance with the User’s
Manual.

- Check the seal on the gas and water sides.

- Check that the ignition operates correctly and visually check the
burner flame.

- Check that the domestic hot water is being correctly produced
by drawing hot water. Check the rate of flow and/or temperature
of the water, depending on the case.

- Check that the condensate drips without difficulty into the
discharge.

- Make a note of the value here.Value from table:................l/min.

- Identify the volumetric rate of flow at the gas meter and compare
it with that of the table.

- Differences greater than +/- 5 % are not allowed: contact the
Authorised Service Centre and do not place the boiler in
operation.

B) H

EATING:

The thermal power is set in the factory at 70% of the maximum
power (the potentiometer corresponds to the value on the display). In
the event that this setting has to be changed, these steps should be
followed:

- open the control panel after having unscrewed the plastic

fastening screws and lift up the rubber stopper protecting the
potentiometers (see section 3.7.1.). Rotate the potentiometer PR
to the desired point, checking the set thermal power on the
display (as described in section 3.6.3.) and on the table below.

Test:

- Turn the selector knob “A” to the flue test position.

- Do not draw hot water.

N

OTE: The test of the volumetric rate of flow must be carried out for at

least five minutes of boiler operation.

- Identify the volumetric rate of flow from the table and make a
note of it here.
Value from the table: ……….l/min.

- Identify the volumetric rate of flow at the gas meter and compare
it with that of the table.

CATEGORY LPG

• Diameter of 6 nozzle holes (mm)

• Display of recommended soft-light

NATURAL GAS

G20

2.7
70

(about 19 kW)

G30 G31

1.7
70

(about 19 kW)

1.7
70

(about 19 kW)

6. MAINTENANCE

6.1. GENERAL REMARKS

It is recommended that the following inspections be carried out on
the boiler at least once a year:

1. Check the seals in the water group and, if necessary, replace
the gaskets and restore the seal to perfect working order.

2. Check the seals in the gas group and, if necessary, replace the
gaskets and restore the seal to perfect working order.

3. Visually check the overall state of the boiler.

4. Visually check the combustion and, if necessary, disassemble

and clean the burner.

5. Following inspection 3, disassemble and clean the combustion
chamber, if necessary.

6. Following inspection 4, disassemble and clean the injector, if
necessary.

7. Clean the primary heat exchanger (see section 6.2)

8. Regulate the correct rate of flow of the gas: rate of flow on

ignition, partially loaded and at maximum load.

9. Check the correct functioning of the heating safety devices:

- temperature limit safety device.

10. Check the correct functioning of the gas group safety devices:

- absence of gas or flame safety device (Ionisation).

11. Check that the electrical connections are correct (in conformity
with the instructions manual).

12. Check the efficiency of the production of domestic hot water
(test the rate of flow and temperature).

13. Carry out a general inspection of the functioning of the boiler.

14. Check the characteristics for expulsion of the products of

combustion.

15. Remove the oxide from the detection electrode by means of an
emery cloth.

CLEANING THE EXHAUST SIDE
Remove the combustion chamber inspection hatch (20) (see section

1.3). Check that the exhaust passages between the blades of the

block are free; if there are deposits present, wash the blades with
compressed air, water or a vinegar-based detergent.
NOTE: it is possible to use a brush in order to mechanically remove
the residues.
Use of detergents:

- soak the blades well

- allow the detergent to act for about 20 minutes

- rinse with a strong jet of water to remove the deposits (the
control panel must be kept closed)

- make sure that there are no traces of detergents in the
exchanger.

CLEANING THE WATER SIDE
Use detergents that dissolve CaCO3. Leave to act for a short time
(in order not to damage the aluminum) and then rinse. Make sure
that the detergent does not remain inside the exchanger.

Unscrew the lower part of the condensate trap and clean it. Lastly, fill
it with water and replace the stopper.

NB: if the boiler is not to be used for a prolonged period, the
condensate trap should be filled before igniting it again. A shortage
of water in the trap is dangerous because there is the risk of exhaust
fumes escaping into the air.

22

275

The boiler is capable of managing a heating system that uses zone
valves. The electr ical connection of these valves is carried out by
means of the appropriate terminal board (indicated in the

“E

LECTRICAL CONNECTION” section).

By way of example, two possible types of systems would be:

1. System with 2 valves with independent regulation of the zones
(day and night).

2. System with 1 valve (regulation of the night zone subordinated to
that of the day).

A possible set-up for the first type of system is as follows:

5. ZONE V AL VES

CR = remote control
VZ1,2 = zone valve 1 and 2
TA = roomstat or timer-thermostat

= radiators
F,N = electrical connection (live and neutral)
RL = relay

A possible set-up for the system with a single zone valve is as
follows:

This set-up is simpler and more economical because it does not
involve the use of the special relay. The night zone, however, may
only be heated during the time periods in which the remote control
timer gives consent to the heating of the day zone. Example:

• day zone programming (remote control): 8-22

• night zone programming (timer-thermostat): 20-22

6.2. C

LEANING THE P

RIMARY EXCHANGER

6.3. CLEANING THE CONDENSATE TRAP

23

275

6.4. OPERATIONAL TEST

After having carried out the maintenance operations, fill the heating
circuit to a pressure of approx.1.5 bar and release the air from the
system. Also fill the domestic hot water system.

- Place the boiler in operation.

- If necessary, release the air again from the heating system.

- Check the settings and the correct functioning of all the control,

regulation and monitoring parts.

- Check the seal and the correct functioning of the system for

expelling fumes/drawing of combustion air.

- Check that the boiler ignites properly and carry out a visual

check on the burner flame.

7. TECHNICAL INFORMATION

Certification 63AT4528
Category II2H3B/P
Thermal Capacity min/max kW 8/24
Usable Thermal Power min/max (30/40°C) kW 8.8/26.1
Usable Thermal Power min/max (60/80°C) kW 7.9/23.3
Usable Thermal Power min/max (30/50°C) kW -/24.5
Power for Hot Water Production min/max kW 7.9/23.3
Efficiency at Nominal Thermal Capacity (30/50°C) % 102.2
Efficiency at 30% of Nominal Thermal Capacity (47°C of return) % 96.4
Efficiency at 30% of Nominal Thermal Capacity (30°C of return) % 103.6
Gas Consumption after 10 Minutes* m

3

0.42
Maximum Heat Loss to the Casing (∆T=50°C) % 0.6
Flue Heat Loss with Burner Operating % 2.1
Flue Heat Loss with Burner Off % 0.2
Maximum Discharge of Fumes Kg/h 35.1
Maximum Temperature of Discharge Fumes °C 66.7
Temperature of Discharge Fumes when Heating 30/40°C (1 m of coax.) °C 42.9
Minimum Room Temperature °C5
Heating Temperature min/max (High Temperature range) °C 42/82
Heating Temperature min/max (Low Temperature range) °C 30/75
Temperature of Water for Domestic Use min/max °C 36/56
Class NOX 5
CO

2

Content % 9.3
O2Content % 4
CO Content ppm 53.5

Inlet Pressure/Methane Gas G20 (boiler at maximum) mbar 20
Inlet Pressure/Liquid Gas G30 - G31 (boiler at maximum) mbar 30
Residual Discharge Head mbar(Pa) 0.65(64)
Maximum Head Loss on Water Side (∆T=20°C) mbar 200
Residual Head of System (60/80°C) bar 0.2
Maximum Heating Pressure bar 3
Maximum Water Content in System l 130
Expansion V essel Capacity l 7
Expansion Vessel Pre-load Pressure bar 1
Pressure of Water for Domestic Use min/max bar 0.2/8-10
Nominal Capacity of Hot Water for Heating (residual head 0.25 bar) l/h 820
D.H.W.Flow Rate: ∆T=25°C l/min 13.4

∆T=30°C l/min 11.1
∆T=35°C l/min 9.6

D.H.W.Flow Minimum Rate l/min 2.5
Quantity of Condensed Water with a (30/40°C) l/h 1.8
pH Condensation Value 3.5÷4
Electrical Supply V/Hz 230/50
Power Consumption W 130
Protection Grade of Electrical System IP 4XD
Internal Fuse Rating A 3.15 SLOW
Width mm 465
Height mm 890
Depth mm 385
Central Heating Connections BSP 3/4
Domestic Hot Water Connections BSP 1/2
Gas Connection BSP 3/4
Net Weight Kg 45

G.C. Number 41-116-17

63AT4528

II2H3B/P

8/24

8.8/26.1

7.9/23.3

-/24.5

7.9/23.3

102.2

96.4

103.6

0.42

0.6

2.1

0.2

35.1

66.7

42.9
5

42/82
30/75
36/56

5

9.3
4

53.5
20
30

0.65(64)
200

0.2
3

130

7
1

0.2/8-10
820

---

---

---

---

1.8

3.5÷4

230/50

130
4XD

3.15 SLOW
465
890
385

3/4
1/2
3/4

44.5

41-116-03

24 MFFI 24 RFFI SYSTEM

*Calculated at 70% maximum output

23 99 84 1439 112

Manufacturer: Merloni TermoSanitari 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]

Servicing
Instructions
Type C Boilers

G.C.N: 41-116-03

47-116-17

LEAVE THESE INSTRUCTIONS
WITH THE END-USER

Condensing

Country of destination: GB

2

1. SERVICING INSTRUCTIONS

1.1 REPLACEMENT OF PARTS

1.2 TO GAIN GENERAL ACCESS

- Lowering the control panel and removing the front panel

- Removing the side panels

1.3 A

CCESS TO THE COMBUSTION CHAMBER

- Removing the sealed chamber front cover

- Removing the fan

- Removing the burner

- Removing the electrodes

- Removing the heat exchanger inspection panel

- Removing the condensate collector

- Removing the condensate trap

- Removing the injector

1.4 A

CCESS TO THE GAS VALVE

- Removing the gas valve

1.5 A

CCESS TO THE WATER CIRCUIT

- Removing the D.H.W.(secondary) exchanger

- Removing the safety valve

- Removing the automatic air vent

- Removing the main circuit flow switch

- Removing the diverter valve actuator

- Removing the D.H.W.flow switch

- Removing the pump

- Removing the pressure gauge

- Removing the expansion vessel

- Removing the D.H.W.temperature sensor (N.T.C.)

- Removing the C.H.flow temperature sensor (N.T.C.)

- Removing the C.H.retur n temperature sensor (N.T.C.)

1.6 A

CCESS TO THE CONTROL SYSTEM

- Checking the fuses

- Removing the time clock

- Removing the P.C.B.s

2. FAULT FINDING

2.1 FAUL T FINDING GUIDE (FLOW-CHART)

3. ELECTRICAL DIAGRAMS

4. SHORT SPARE PARTS LIST

TABLE OF CONTENTS

3

F

IG. 1.2

FIG. 1.1

1. SERVICING
INSTRUCTIONS

The life of individual components vary and they will need servicing or
replacing as and when faults develop.
The fault finding sequence chart in chapter 2 will help to locate which
component is the cause of any malfunction, and instructions for removal,
inspection and replacement of the individual parts are given in the following
pages.

1.1 REPLACEMENT

OF PARTS

1.2 T

O GAIN GENERAL

ACCESS

All testing and maintenance operations on the boiler require the control panel
to be lowered.This will also require the removal of the casing.

To lower the control panel and dismantle the front part of the casing,
proceed as follows:

1. Unscrew screws “A” (1/4 turn only) (F

IG. 1.1 + FIG. 1.2) and rotate the

control panel forward;

2. Unscrew the screws “B” (FIG. 1.3) and unhook the front panel by lifting it.

To ensure efficient safe operation, it is recommended that the boiler is
serviced annually by a competent person.

Before starting any servicing work, ensure both the gas and electrical
supplies to the boiler are isolated and the boiler is cool.

Before and after servicing, a combustion analysis should be made via the flue
sampling point (please refer to the Installation Manual for fur ther details).

After servicing, preliminary electr ical system checks must be carried out to
ensure electrical safety (i.e. polarity, earth continuity, resistance to earth and
short circuit).

B

A

A

A

B

FIG. 1.3

4

Removing the side panels

1. Remove the screws “C”(F

IG. 1.4);

2. Pull each panel away from the boiler, then lift the panel
up and away from the boiler.

1.3 ACCESS TO THE
COMBUSTION CHAMBER

D

FIG. 1.5

D

FIG. 1.4

C

C

C

C

D D

Removing the sealed chamber front cover

1. Remove the screws “D”(F

IG. 1.5);

2. Pull the cover away from the boiler (FIG. 1.6).

FIG. 1.6

5

Removing the fan

1. Loosen nut “E” (F

IG. 1.7);

2. Pull off the hose “F” and disconnect the electrical
connector “G” (FIG. 1.8);

3. Remove the nuts “H” (F

IG. 1.9);

4. Pull the fan away from the exchanger (FIG. 1.10).

FIG. 1.10

E

FIG. 1.9

FIG. 1.7

FIG. 1.8

F

G

H

H

H

6

Removing the burner

With the fan removed (see previous section);

1. Slide the burner from its housing (F

IG. 1.11).

F

IG. 1.13

J

I

J

Removing the electrodes

1. Pull off the ignition cable “I” (F

IG. 1.12);

2. Remove the two allen bolts “J” (FIG. 1.13);

3. Extract the electodes (F

IG. 1.14).

FIG. 1.12

FIG. 1.11

FIG. 1.14

Removing the combustion chamber inspection panel

1. Remove the four nuts “K” (F

IG. 1.15);

2. Remove the inspection panel (FIG. 1.16).

FIG. 1.15

KK

FIG

. 1.16

K

K

7

Removing the condensate collector

1. Remove the nuts “L” from each side of front of the

collector (F

IG. 1.17);

2. Remove the nuts “M” from each side of rear of the
collector (F

IG. 1.18);

3. Release the condesate trap union “N” (FIG. 1.19);

4. Separate the collector from the combustion

chamber(F

IG. 1.20);

5. Remove the condensate collector (FIG.1.21).

FIG. 1.17

L

FIG. 1.18

M

FIG. 1.19

FIG. 1.20

FIG. 1.21

N

8

Removing the condensate trap

1. Loosen the union “O” (FIG. 1.22);

2. Remove the condensate trap (FIG. 1.23).

FIG. 1.22

O

Removing the injector

See the section on removing the fan before carring out this
procedure

1. Disconnect all connections from the fan and remove
(F

IG. 124);

2. Remove the four screws “P” (FIG. 125);

3. Unscrew the injector “Q” using a suitable screwdriver

(FIG. 126);

4. Remove the injector (FIG.127).

Fig. 1.23

Fig. 1.24

Fig. 1.25

P

9

FIG. 1.26

F

IG. 1.27

Q

10

1.4 ACCESS TO THE GAS VALVE

F

IG. 1.28

S

R

Removing the gas valve

1. Disconnect the electrical connection “R” from the gas

valve (F

IG. 128);

2. Release the top nut “S” (FIG. 1.29);

3. Remove the screws “T” from the bottom of the gas valve

pipe (F

IG. 1.30);

4. Remove the gas valve (FIG. 1.31).

FIG. 1.29

FIG. 1.30

FIG. 1.31

T T

11

Removing the safety valve

1. Loosen union “W”(Fig. 1.35);

2. Unscrew and remove the valve (Fig. 1.36).

1.5 ACCESS TO THE WATER CIRCUIT

FIG. 1.36

Removing the D.H.W. (secondary)
exchanger

1. Remove the screw “U” (F

IG. 1.32);

2. Remove the screw “V” (F

IG. 1.33);

3. Push the exchanger towards the rear of the boiler, lift
upwards and remove from the front of the boiler (FIG.

1.34);

4. Before replacing the exchanger ensure that the O-rings
are in good condition and replace if necessary.

Important! Before any component is removed, the boiler
must be drained of all water.

F

IG. 1.34

F

IG. 1.35

U

FIG. 1.32

FIG. 1.33

V

W

12

Removing the automatic air vent

1. Unscrew valve “X” (F

IG. 1.37);

2. Remove (FIG. 1.38).

Removing the main circuit flow switch

1. Release the retaining clip “Y” (F

IG. 1.40);

2. Remove the main circuit flow switch.

FIG. 1.37

FIG. 1.38

FIG. 1.40

X

Y

B1

Z

A1

FIG. 1.41

Removing the diverter valve actuator

1. Unplug the electr ical connector “Z” (F

IG. 1.41);

2. Release the retaining clip “A1” and remove the diverter
valve actuator (FIG.1.42).

Removing the D.H.W. flow switch

1. Release the retaining clip “B1” (F

IG. 1.43);

2. Remove the D.H.W. flow switch.

FIG. 1.42

FIG. 1.43

13

Removing the pump

1. Unplug the electrical connection “C1” (F

IG. 1.44);

2. Release the nut “D1”(FIG. 1.45);

3. Release the nut “E1”(FIG. 1.46);

4. Remove the pump (F

IG. 1.47).

E1

D1

C1

FIG. 1.44

FIG. 1.47

FIG. 1.46

F

IG. 1.45

14

Removing the expansion vessel

See the section on removing the condesate trap before
carrying out this procedure

1. Loosen nut “H1” (F

IG. 1.51);

2. Loosen nut “I1” and remove backnut “J1” (FIG. 1.52);

3. Remove the expansion vessel (FIG.1.53).

Removing the pressure gauge

1. Release coupling “F1” (F

IG. 1.48);

2. Ease the pressure gauge “G1”through the control panel
from the rear (FIG. 1.49);

3. Remove the pressure gauge. (F

IG 1.50).

F1

G1

F

IG. 1.48

FIG. 1.49

FIG. 1.50

H1

I1

F

IG. 1.51

FIG. 1.52

FIG. 1.53

J1

15

Removing the D.H.W. temperature probe (N.T.C.) (MFFI
only)

1. Remove the electrical connector “K1” by pulling off

(Fig. 1.54);

2. Unscrew and remove the D.H.W.temperature probe “L1”

(F

IG. 1.55).

K1

L1

FIG. 1.54

F

IG. 1.55

M1

FIG. 1.56

Removing the C.H. flow temperature probe (N.T.C.)

1. Remove the electrical connector “M1” by pulling off

(Fig. 1.56);

2. Unscrew and remove the C.H.flow temperature probe

“N1” (F

IG. 1.57).

O1

P1

FIG. 1.58

FIG. 1.59

Removing the C.H. return temperature probe (N.T.C.)

1. Remove the electrical connector “O1” by pulling off

(Fig. 1.58);

2. Unscrew and remove the C.H. return temperature probe
“P1” (F

IG. 1.59).

N1

F

IG. 1.57

16

Checking the fuses

1. Remove the inspection cover on the reverse of the

control panel (FIG. 1.60);

2. Remove the fuses by pushing and rotating fuse holders
“Q1” (F

IG. 1.61).

1.6 ACCESS TO THE CONTROL SYSTEM

Removing the time clock

1. Remove the inspection cover on the reverse of the

control panel (F

IG. 1.60);

2. Lower the time clock door (FIG. 1.62);

3. Unplug the electrical connection “R1” from the time clock

(F

IG. 1.63);

4. Gently squeeze each end of the time clock and push
through the control panel (FIG. 1.64).

Q1

FIG. 1.60

FIG. 1.61

FIG. 1.64

F

IG. 1.62

FIG. 1.63

R1

17

Removing the P.C.B.s

1. Remove the inspection cover on the reverse of the

control panel (F

IG. 1.60);

2. Remove the screws “S1” (FIG. 1.65 & FIG. 1.66);

3. Remove the facia panel (FIG. 1.67);

5. Disconnect the connection cable ”T1” (F

IG. 1.68);

6. Unplug the electrical connectors “U1” from the main
P.C.B. (Fig. 1.69);

7. Remove the main P.C.B. mounting screws “V1’ (four in
total) (F

IG. 1.70);

8. Remove the main P.C.B. (FIG. 1.71);

9. Remove the display P.C.B. mounting screws “W1’ (F

IG.

1.72);

10.Remove the display P.C.B.(F

IG. 1.73);

11.Replace either P.C.B. in reverse order.

FIG. 1.67

S1

FIG. 1.65

FIG. 1.66

S1

FIG. 1.70

T1

FIG. 1.68

FIG. 1.69

U1

S1

S1

U1

U1

V1

V1

FIG. 1.71

18

W1

FIG. 1.72

FIG. 1.73

W1

W1

W1

19

2. FAULT FINDING

It is possible to detect and correct any defect by using the standard fault
finding diagrams described in this chapter.

2.1 FAULT FINDING GUIDE

(FLOW-CHARTS)

Model 24 MFFI

TABLE
I and II

SUMMER

MAKE SURE THAT:

1. There is sufficient water in the system

2. The gas is turned on

3. The electrical supply is turned on

PUSH THE ON/OFF

BUTTON TO ON

NO

1. Check the fuses

2. Check the power supply to
the control panel

3. Check/replace the
ON/OFF button

4. Check the connection between
the main and display P.C.B.s

5. Check/replace the
main and display P.C.B.s

WINTER

YES

IS THE

POWER L.E.D. AND

DISPLAY ON?

DOES A STOP CODE

APPEAR ON THE DISPLAY?

POSITION OF THE SUMMER/

WINTER SELECTOR

COMFORT

SELECTOR ON/OFF:

green L.E.D. on

NO:

COMFORT OFF

D.H.W.
IS BEING
DRAWN?

NO

BUILT-IN

ELECTRONIC

ANTI-FROST DEVICE:

Is there a condition for it to be active?

- outdoor temp. < -3°C (outdoor sensor optional)

(- flow temp. < 3°C

- Jumper 4 selects the pump
for continuous

operation)

YES: COMFORT ON

temperature

<40°C

temperature

>50°C

YES

Flow

Flow

NO

YES

YES

YES

NO

YES

NO

YES: COMFORT ON

Flow

temperature

<40°C

NO

Flow

temperature

>50°C

YES

YES

YES

- outdoor temp. < -3°C (outdoor sensor optional)

COMFORT

SELECTOR ON/OFF:

green L.E.D. on

NO:

COMFORT OFF

YES

AND/OR ROOM THERMOSTAT

Is there a condition for it to be active?

- Jumper 4 selects the pump

D.H.W.
IS BEING
DRAWN?

NO

MUST

THE TIME CLOCK

BE ACTIVATED?

NO

BUILT-IN

ELECTRONIC

ANTI-FROST DEVICE:

(- flow temp. < 3°C

for continuous

operation)

NO

THERE IS NO CALL FOR PUMP OPERATION

NO

THERE IS NO CALL FOR PUMP OPERATION

A

20

Model 24 RFFI System

MAKE SURE THAT:

1. There is sufficient water in the system

2. The gas is turned on

3. The electrical supply is turned on

PUSH THE ON/OFF

BUTTON TO ON

SELECTOR

ON (green L.E.D. on):

cylinder excluded

C.H. ONLY

ON/OFF

TABLE
I and II

SUMMER

YES

OFF (green L.E.D. off):

cylinder active

The

C.H. flow

temperature

is lower than 80°C

and the temperature of the

cylinder is at least 5°C

below the one

selected.

NO

IS THE

POWER L.E.D. AND

DISPLAY ON?

DOES A STOP CODE

APPEAR ON THE DISPLAY?

POSITION OF THE SUMMER/

WINTER SELECTOR

OFF (green L.E.D. off):

YES

YES

and the temperature of the

cylinder is at least 5°C

NO

1. Check the fuses

2. Check the power supply to
the control panel

3. Check/replace the
ON/OFF button

4. Check the connection between
the main and display P.C.B.s

5. Check/replace the
main and display P.C.B.s

WINTER

cylinder active

The

C.H. flow

temperature

is lower than 80°C

below the one

selected.

NO

C.H. ONLY

SELECTOR

ON/OFF

ON (green L.E.D. on):

cylinder excluded

BUILT-IN

ELECTRONIC

ANTI-FROST DEVICE:

Is there a condition for it to be active?

- outdoor temp. < -3°C (outdoor sensor optional)

THERE IS NO CALL FOR PUMP OPERATION

(- flow temp. < 3°C

- Jumper 4 selects the pump
for continuous

operation)

NO

YES

A

YES

MUST

THE TIME CLOCK

AND/OR ROOM THERMOSTAT

BE ACTIVATED?

NO

BUILT-IN

ELECTRONIC

ANTI-FROST DEVICE:

Is there a condition for it to be active?

YES

- outdoor temp. < -3°C (outdoor sensor optional)

THERE IS NO CALL FOR PUMP OPERATION

(- flow temp. < 3°C

- Jumper 4 selects the pump
for continuous

operation)

NO

21

Model 24 MFFI/24RFFI System

A

IS THE

PUMP RUNNING?

YES

B

NO

NO

1. Check if there is air in
the system

2. Check the main circuit flow
switch operation

3. Check the pressure on the
water gauge and fill system
to 1 bar

YES

Push the

RESET button

POWER TO

THE PUMP?

YES

IS

THE MAIN

CIRCUIT FLOW SWITCH

WORKING CORRECTLY?

A21: does not close
A22: does not open

YES

Release/replace

pump

NO

1. Check pump cable

2. Check/replace
main P.C.B.

22

Model 24 MFFI/24RFFI System

B

IS THE FAN

RUNNING?

YES

SPARKS ARE GENERATED

IGNITION

REGULARLY?

YES

IS THE BURNER

ALIGHT?

YES

NO

NO

DOES CODE

A33 APPEAR?

Replace

the main P.C.B.

1. Check/replace ignition

NO

electrode

2. Check ignition cable

3. Check/replace the main P.C.B.

1. Check the power supply
of the gas valve.

2. Check for an air
pressure signal

3. Check the gas pressure
on the burner

4. Check the soft-light
adjustment

5. Replace the gas valve

6. Check/replace the
main P.C.B.

NO

YES

1. Check the fan cable

2. Replace the fan

3. Replace the main P.C.B.

IS
THERE STILL
A PROBLEM?

NO

NORMAL

OPERATION

YES

BOILER HAS
SHUTDOWN?

1. Table II

2. Press RESET

1. Table III

NO

YES

23

T

ABLE I

TABLE III

DISPLAY

A01

A02

A03

A07

A19

A20

A21

A22

A33

A99

C

AUSE

Too many attempts to ignite on starting up
After three attempts at ignition, no increase in ∆T was detected
The heating flow temperature exceeds 100°C during operation
Too many failures to flame in one period during operation
The flame was detected after the gas valve had closed
The flame was detected before the gas valve opened
The flow switch does not close
The flow switch does not open
Problem with the fan
Problem with the electronic monitoring

TABLE II

DISPLAY

E03

E56

E66

E04

E05

E08

E20

E21

E22

E23

E64

E74

E99

C

AUSE

Flow temperature over 100°C while boiler is not in operation
(stand-by)
Heating flow temperature probe in open circuit
Heating flow temperature probe
Domestic hot water temperature probe in open circuit
Domestic hot water temperature probe in short circuit
Under floor heating temperature probe in open circuit
Flame detected with gas valve closed
Error in the electrical connection (live and neutral crossed)
Problem with the 50Hz power supply
Flame detection electrode short-circuited
Heating return temperature probe in open circuit
Heating return temperature probe in short circuit
Problem within the electronic system

F

AULTS

1. Drawing D.H.W:

Radiators heat up in summer
mode

2. Drawing D.H.W:
Insufficient hot water temperature

3. Drawing D.H.W:
Noisy operation

4. Decrease/increase heating circuit
pressure

5. When cold water tap turned off, the
boiler ignites

6. Insufficient radiator temperature

P

OSSIBLE CAUSES

- faulty 3-way valve

- check C.H./D.H.W. temperature probes

- check gas pressures

- check water flow rate

- check secondary heat exchanger

- primary heat exchanger faulty or lime-scale deposits

- low heating system water pressure

- check gas pressures

- check C.H./D.H.W. temperature probes

- check for leaks on the heating circuit

- faulty filling-loop

- faulty secondary heat exchanger

- expansion vessel faulty

- drop in pressure in the water mains, with
consequent water hammer

- check C.H.temperature probe

- check by-pass

- check gas pressures

24

3. ELECTRICAL
DIAGRAMS

LEGEND

:

A:JUMPER
When needed, the P.C.B.allows the different options to be selected by means of
a wire link.
The boiler has the following basic arrangement:

1 OPEN
2 CLOSED (jumper)
3 OPEN
4 OPEN
5 OPEN
6 OPEN
7 CLOSED
8 OPEN (MFFI); CLOSED (SYSTEM)

N

OTE

: under absolutely no circumstances must jumpers 2, 7 and 8 be removed.

The opening of such contacts will lead to boiler malfunction.
This is the factory configuration. It is recommended that this set-up not be

changed, unless under the following particular circumstances:
JUMPER 3: if the contact is closed, the Secondary Output (flying clamp

connected to connection C7; positions 1-9) controls a LPG valve
(optional).

JUMPER 4: if the contact is closed, the continuous operation of the pump is

selected. If the contact remains open, it has no effect and there is
no change in the operation of the boiler.

JUMPER 5: if the contact is closed, the signal transmitted by the connection of

the secondary output clasp (connected to C7; positions 1-9)
relates to a secondary pump (optional). If the contact remains

open, the output signal controls a zone valve (optional).
JUMPER 6: not used
JUMPER 7/8:

I = inser ted (contact closed)
N.I = not inserted (contact open)

N

OTE: it is essential that the operations involving setting of the jumpers be

carried out only with the device turned off.
B: Control microprocessor
C: Flame detection jumper (under no circumstances should this jumper be

moved from the 1-2 position)
D: Anti-cycling device (RA)
E: Maximum heating output regulation (PR)
F: Soft-light regulation (RLA)
G: Operating mode selector knob
H: Heating temperature adjustment
I: Domestic hot water temperature adjustment
J: Remote control module
K: Main microprocessor
L: Relay
M: Fuses (2 x 0.54 A SLOW)
N: Transformer (PRI: 230V-50Hz; SEK: 10V-0,8VA; SEK:10V-3,5VA; SEK:10V-

3,5VA;)
O: Fuses (2 x 3.15 A SLOW)
P: Earth
Q: Spark generator
R: Connection to the main P.C.B.
S: Comfor t light
T: Programming keys
U: Comfort key
V: Alpha-numeric display
X: Set and reset key
W: Connection to PC

7

N.I.

I.

N.I.

I.

8

N.I.
N.I.

I.
I.

CONFIGURATION

Central heating only
MFFI
Not used
RFFI System

25

C1 = FAN

1: “Hall” sensor power supply 12V (red)
2: “Hall” sensor ground (blue)
3: Not used
4: Start of coil (black)
5: “Hall” sensor input (white)
6: End of coil (brown)

C2 = POWER SUPPLY

1: Earth (yellow/green)
2: Earth (yellow/green)
3: Not connected
4: Neutral (blue)
5: Not connected
6: Live (brown)

C3 = CONNECTION TO ROOMSTAT

1: Input - 1
2: Input - 2

C4 = TIMER

1: 3 V output
2: Timer ground
3: Timer output
4: Not connected

C5 = REMOTE CONTROL (Bus+/Bus-)

1: Input/output-1
2: Input/output-2

C6 = SENSOR CONNECTOR

1: Domestic hot water flow switch (grey)
2: Main circuit flow switch (grey)
3: Under floor heating ther mostat (grey)
4: Heating flow sensor (grey)
5: Heating retur n sensor (grey)
6: Domestic hot water sensor (grey)
7: Not used: jumper
8: Outdoor sensor (grey)
9: Domestic hot water flow switch (grey)
10: Main circuit flow switch (grey)
11: Under floor heating ther mostat (grey)
12: Flow sensor (grey)
13: Heating sensor (grey)
14: Domestic hot water sensor (grey)
15: Not used: under floor heating
16: Outdoor sensor (grey)

C7 = EQUIPMENT CONNECTIONS

1: Secondar y output (optional)
2: Gas valve (white)
3: 3-way valve neutral (white)
4: Pump (white)
5: Ionisation (black)
6: Not connected
7: Ground
8: Pump earth (yellow/green)
9: Secondar y output (optional)
10: Gas valve (brown)
11: 3-way valve (domestic hot water) (brown)
12: 3-way valve (heating) (brown)
13: Pump (brown)
14: Not connected
15: Earth
16: Gas valve earth (yellow/green)

26

ecoGENUS 24 MFFI - ecoGENUS 24 RFFI

27

4. SHORT SPARE
PARTS LIST

ecoGENUS - 24 MFFI

1

2

3

56 492 51 52

57

3

53 50 49 48 464754 5255

51

57

3

3

3

4

5

6

7

8

9

10

7

11
12
13

7

81

7

17

16

76

78

1715 23 25242216 18

3

57

57

65

66

75

74

73

77

79

80

81

82

19

19 21148

71

84

83

84

20

64

67

68

7

69

72

70

88

58

59

60

62

61

63

58

8

95

94

93

91

89

86

87

85

108

107

106

59

96

92

90

97

98
99

26 27 29

3

59

105

104

103

102

101

37
36

100

33

28

28

3

301302301

45

44

43

42
41

40

39
38

37
36

35
34

33
32
31

30

311

336

312

21 15

313

331

335

332

333

334

13

333

24 MFFI

28

573294
573520
569236
997147
997077
998127
571438
998802
998144
573727
573172
573528
997207
571649
998765
569390
998672
998668
998459
998889
998888
998651
998077
998894
997206
997151
569387
573521
564264
998791
998792
573768
998801
998670
571444
571441
574248
998490
571987
571441
574248
571447
998013

Key

no.

G.C. part

no.

ARISTON

Part No.

Description

1
7
8

11
12
13
15
20
21
22
23
24
30
38
41
42
62
64
70
72
73
75
78
80
81
83
84
87
89
90
91
92
97

106
311
312
313
331
332
333
334
335
336

164 225
164 338
E25 427
E25 429

378 814
E26 378
164 229
E26 819
E25 437

164 261

E26 657
E26 658
E25 518
164 230
164 282
379 079

E25 581

E24 077

Expansion vessel
Gasket 3/4"

Temperature probe (C.H.W.)
Motor (3-way valve)
Fixing clip (motor)
Flow group
Gas valve
Micro switch set (main flow & D.H.W.)
Return group
Manual vent cock
Safety valve 1/2" 3 bar)
Gasket 1/2"
Time clock
Pressure gauge
P.C.B. (display)
Gasket 1/4"
Electrode (ignition/detection)
Burner
Electrode cable (resistive)
Fan cable & sensor
Fan
Injector (G20)
O-ring gasket
Secondary exchanger (p-type 27kW)
O-ring (secondary exchanger)
Pump
Gasket 1"
Gasket 3/8"
Auto air vent
Condensate Trap
Cap (trap filling)
Gasket (airtight - condensate trap)
P.C.B. (main)
Main exchanger (aluminium)
D.H.W. actuator Kit
Heating pressure switch kit
Pressure cover
Central heating by-pass kit
D.H.W. pressure switch kit
Heating pressure switch kit
Pressure cover
3-way spring kit
Heating actuator bush

1
1

1
1
1

1
1
1
1
1
1
1
1
1
1
1
1
1

1
1

1
1

1
1
1

1
1
1
1
1
1
1
1
1
1
1
1

E25 417

ecoGENUS - 24 MFFI

29

ecoGENUS - 24 RFFI SYSTEM

572 52 53

50

1

2

3

3

58

3

3

54 51 50 49 474855 5356

52

3

58

3

3

3

58

4

5

6
7

8

9

7

10
11

12
13

14

1615

76

7

77

7

19

18

8

78

1917 18 20

58

66

67

75

74

73

72

80

79

80

81
11

65

68

69

7

70

71

7

23

59

60

61

63

62

64

59

8

93

92

91

89

90

88

84

83

82

25 26212421 2122

106

105

104

301302301

60

103

102

60

94

87

86

85

95

96
97

101

100

99

38
37

27 28 30

98

34

29

29

46

45

44

43
42

41

40
39

38
37

36
35

34
33
32

31

336

23 17

335

333

334

331

14

332

333

24 RFFI SYSTEM

30

573294
573520
569236
997147
997077
998456
571438
573528
997828
573727
573172
997207
571649
998765
569390
998672
998668
998889
998888
998651
998783
997151
569387
573521
998791
573768
998792
564254
998459
998801
998670
571987
571443
571441
574248
571447
998013

Key

no.

G.C. part

no.

ARISTON

Part No.

Description

1
7
8

12
13
14
17
21
23
24
25
31
39
42
43
63
65

71
73

79
80
84
86
87
88
90
91

95
104
331
332
333
334
335
336

75A
75B

164 225
164 338
E25 427
E25 429

164 229
378 814

E26 378
E26 819
E25 437

164 261

E25 518
164 230
164 282

379 079

E24 077

Expansion vessel
Gasket 3/4"

Temperature probe (C.H.W.)
Motor (3- Way valve)
Fixing clip (motor)
Flow group
Gas valve
Gasket 1/2"
Return group
Manual vent cock
Safety valve 1/2" 3 bar)
Time clock
Pressure gauge
P.C.B. (display)
Gasket 1/4"
Electrode (ignition/detection)
Burner
Fan cable & sensor
Fan
Injector (G20)
Injector (G30)
Pump
Gasket 1"
Gasket 3/8"
Condensate Trap
Gasket (airtight - condensate trap)
Cap (trap filling)
Auto air vent
Electrode cable (resistive)
P.C.B. (main)
Main exchanger (aluminium)
D.H.W. pressure switch kit
Central heating by-pass kit
Heating pressure switch kit
Pressure cover
3-way spring kit
Heating actuator bush

1
1

1
1
1

1
1
1
1
1
1
1
1
1
1
1
1
1

1
1

1
1

1
1
1

1
1
1
1
1
1
1
1
1
1
1
1

E25 417

ecoGENUS - 24 RFFI SYSTEM

Manufacturer: Merloni TermoSanitari 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]

SPARE PARTS EXPLODED VIEW
GAS WALL BOILERS

Models

ECOGENUS 24 MFFI

Edition 1 of 1 December 1999

56 492 51 52

1

2

3

3

57

53 50 49 48 464754 5255

51

3

3

57

10

11
12
13

3

3

92

90

108

96

107

106

97

98
99

37
36

26 27 29

57

89

91

62

59

93

94

58

60

61

58

8

59

95

87

75

74

20

83

71

57

84

66

84

72

67

68

65

64

63

7

69

70

88

86

85

4

5

6

7

8

9

7

821

81

17

16

76

73

7

77

78

79

80

81

82

7

19

1715 23 25242216 18

1914

3

59

105

104

103

102

101

100

33

28

28

3

301302301

45

44

43

42
41

40

39
38

37
36

35
34

33
32

31

30

311

336

code 998144

312

335

313

331

code 571438

code 998127

332

333

334

333

MODELS CHARACTERISTICS SERIAL NO:

REF.

VALIDITY

ECOGENUS 24 MFFI METHANE 9933500098 A

PART. CODE DESCRIPTION REF. NOTE

1 573294 Expansion vessel
2 573310 Expansion vessel insert
3 574302 Casing support bracket (Plastic)
4 573244 3/8" lock nut
5 ------ Frame 11
6 ------ Hydraulic group support 11
7 573520 Gasket 3/4"
8 569236 Temperature probe (C.H.W.)

9 998655 Pipe (C.H. flow)
10 998656 Pipe (gas valve/burner jet)
11 997147 Motor (3-Way valve)
12 997077 Fixing clip (motor)
13 998127 Flow group
14 570615 1/8" Brass plug
15 571438 Gas valve
16 565048 O-ring gasket (gas valve)
17 998665 Union (gas valve)
18 573793 Intake (pressure - control valve)
19 573824 Bracket (M/Flow Micro Switch)
20 998802 Micro switch set (main flow & D.H.W.)
21 998144 Return group
22 573727 Manual vent cock
23 573172 Safety valve (1/2" 3 bar)
24 573528 Gasket 1/2"
25 573311 Pipe (expansion vessel)
26 998674 Wiring (power supply)
27 573302 Summer/Winter selector kit
28 998747 Control knob kit
29 998661 Door (instruction/time clock)
30 997207 Time clock
31 998772 On/off push button kit
32 998778 Control panel (front)
33 998751 Button (reset)
34 999073 Cover (display)
35 998766 Film (display)
36 998381 Pin (front cover)
37 998739 Fixing spring (front cover)
38 571649 Pressure gauge
39 ------ Control panel 11
40 571562 Cable clamp
41 998765 P.C.B. (display)
42 569390 Gasket 1/4"
43 ------ Cover (connectors) 11
44 999060 Low voltage wiring
45 998676 High voltage wiring
46 998076 View window glass gasket
47 998075 View window glass
48 574104 Panel (sealed chamber - front)
49 573247 Panel (sealed chamber - side)
50 ------ Sealed chamber 11
51 573865 Flue gasket
52 573330 Air return cover
53 573326 Flue intake plug
54 998474 Flue exhaust manifold / header
55 573337 Gasket (flue manifold)
56 572984 Casing support bracket
57 570717 Spring (fastening)
58 998666 Nipple (gas - 3/4" M/M)
59 998785 Dowel (M6x35)
60 998782 View window glass
61 998775 Retaining ring (D=16mm)
62 998672 Electrode (Ignition/Detection)
63 998767 Cap (electrodes)
64 998668 Burner
65 998680 Gasket (elbow)

PART. CODE DESCRIPTION REF. NOTE

66 998788 Elbow (fan)
67 ------ Flame mirror 11
68 998786 Diaphragm (condensing boiler)
69 998654 Pipe (C.H. return)
70 998459 Electrode cable (resistive)
71 999071 Pipe (fan suction silencer)
72 998889 Fan cable & sensor
73 998888 Fan
74 998681 Gasket (fan inlet)
75 998651 Injector (G20)
76 570772 Cable holder
77 998065 By-pass pipe
78 998077 O-ring gasket
79 998064 Spring (by-pass pipe)
80 573295 Secondary exchanger (p-type 27kW)
81 573825 O-Ring (secondary exchanger)
82 573576 Compensation tube
83 997151 Pump
84 569387 Gasket 1"
85 998019 Pipe (safety valve outlet)
86 998567 Safety valve outlet pipe ring nut
87 573521 Gasket 3/8"
88 998413 Pipe (condensate - plastic)
89 564254 Auto air vent
90 998791 Condensate Trap
91 998792 Cap (trap filling)
92 573768 Gasket (airtight - condensate trap)
93 998412 Pipe (drain - plastic)
94 998787 Condensate tray (aluminium)
95 998808 Gasket (adhesive - 10x5 mm)
96 998784 Fixing nut (tray rear)
97 998801 P.C.B. (main)
98 998382 Grommet (regulation access)
99 569720 Blind grommet

100 998653 L.E.D. lens
101 569424 On/off neon switch
102 998460 Gasket (igniter insulation)
103 998777 Aluminium inspection lid
104 573766 Front cover gasket
105 ------ Bottom fixing bracket 11
106 998670 Main exchanger (aluminium)
107 ------ Top fixing bracket 11
108 998423 Lip gasket (D=66 mm)

301 998414 Case panel (side)
302 998478 Case panel (front)

311 571444 D.H.W. actuator Kit
312 571441 Heating pressure switch kit
313 574248 Pressure cover

331 998490 Central heating by-pass kit
332 571987 D.H.W. pressure switch kit
333 571441 Heating pressure switch kit
334 574248 Pressure cover
335 571447 3-Way spring kit
336 998013 Heating actuator bush

NOTE DESCRIPTION

11 Not supplied as a spare part