Ariston Boiler 47 116 15 User Manual

Installation  
Instructions  
Type C Boilers  
G.C.N: 47-116-14  
47-116-15  
LEAVE THESE INSTRUCTIONS  
WITH THE END-USER  
Country of destination: GB  
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.  
1.  
GENERAL  
INFORMATION  
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.  
CO034A  
Read the instructions and recommendations in these Installation Instructions  
carefully to ensure proper installation, use and maintenance of the appliance.  
1.1  
GENERAL INSTRUCTIONS  
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.  
Check the following at least once a year:  
1 - Check the seals for the water connections; replacement of any faulty seals.  
2 - Check the gas seals; replacement of any faulty gas seals.  
3 - Visual check of the entire unit.  
4 - Visual check of the combustion process or analysis of combustion by-  
products (see section 3.6) and cleaning of the burner if needed.  
3
5 - If called for by point. 3, dismantling and cleaning of the combustion  
chamber.  
6 - If called for by point. 4, dismantling and cleaning of the burner jets.  
7 - Visual check of the primary heat exchanger:  
-
-
check for overheating in the blade assembly;  
clean the exhaust fan if needed.  
8 - Adjustment of the flow rate of the gas: flow rate for lighting, partial load and  
full load.  
9 - Check of the heating safety systems:  
-
-
safety device for maximum temperature;  
safety device for maximum pressure.  
10- Check of the gas safety systems:  
safety device for lack of gas or flame ionisation (detection  
electrode);  
-
-
safety device for gas cock.  
11- Check of the electrical connection (make sure it complies with the instructions  
in the manual).  
12- Check of domestic hot water production efficiency (flow rate and temperature)  
13- General check of the combustion by-products of the discharge/ventilation  
system.  
14- Check of the general performance of the unit.  
FIG. 1.0  
1.2  
OVERALL VIEW  
LEGEND:  
1.  
2.  
3.  
Flue connector  
Air intake for twin pipe flue systems  
Fan  
4.  
5.  
Combustion chamber hood  
Main heat exchanger  
6.  
Safety thermostat  
7.  
8.  
9.  
Combustion chamber  
Combustion chamber insulation panel  
Burner  
10.  
11.  
12.  
13.  
14.  
15.  
16.  
17.  
18.  
19.  
20.  
21.  
22.  
23.  
24.  
25.  
Detection electrode  
Ignition electrodes  
Motorised diverter valve  
Main circuit temperature probe  
Main circuit flow switch  
Domestic hot water temperature probe  
Gas valve  
Spark generator  
Domestic hot water flow switch  
Domestic cold water inlet filter  
Secondary heat exchanger  
Circulation pump with automatic air release valve  
Safety valve (3 bar)  
Expansion vessel  
Air pressure switch  
Combustion analysis intakes  
IN013A  
4
The technical information and instructions provided herein below are  
intended for the installer so that the unit may be installed correctly and  
safely.  
2.  
INSTALLATION  
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 .  
2.1  
REFERENCE STANDARDS  
This appliance must be installed by a competent installer in  
accordance with current Gas Safety (installation & use)  
Regulations.  
The installation of this appliance must be in accordance with the relevant  
requirements of the 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:  
Low pressure  
pipes  
BS 6891  
BS 6798  
BS 5449  
1988  
1987  
1990  
Boilers of rated input  
not exceeding 60 kW  
Forced circulation hot  
water system  
Installation of gas hot water  
supplies for domestic purposes  
nd  
( 2 family gases)  
BS 5546  
1990  
1990  
Flues  
BS 5440-1  
Air supply  
BS 5440-2  
1989  
2.2  
SITING THE APPLIANCE  
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 the  
installation within a cupboard.  
This appliance is not suitable for outdoor installation.  
The type C appliances (in which the combustion circuit, air vent intake  
and combustion chamber are air-tight with respect to the room in  
which the appliance is installed) can be installed in any type of room.  
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.  
5
2.3  
OVERALL DIMENSIONS  
LEGEND:  
A = Central Heating Flow (3/4)  
B = Domestic Hot Water Outlet (1/2)  
C = Gas Inlet (3/4)  
D = Domestic Cold Water Inlet (1/2)  
E = Central Heating Return (3/4)  
2.4  
CLEARANCES  
In order to allow for access to the interior of the boiler for  
maintenance purposes, the boiler must be installed in  
compliance with the minimum clearances indicated in FIG. 2.2  
FIG. 2.1  
QT002A  
2.5  
MOUNTING THE APPLIANCE  
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.  
2.7  
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.  
DM004A  
FIG. 2.2  
The boiler operates with alternating current, as indicated in  
the technical information table section in 6, 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)  
IMPORTANT!  
In the event that the power supply cord must be changed,  
replace it with one with the same specifications. Make the  
connections to the terminal board located within the  
control panel, as follows:  
VR001A  
FIG. 2.3  
- The yellow-green wire should be connected to the  
terminal marked with the “  
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  
6
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.  
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.  
2.8  
2.9  
GAS CONNECTION  
VIEW OF THE BOILER CONNECTIONS  
WATER CONNECTIONS  
FIG. 2.4  
SC008A  
KT002A  
FIG. 2.5  
LEGEND:  
A = Central Heating Flow  
B = Domestic Hot Water Outlet  
C = Gas Inlet  
D = Domestic Cold Water Inlet  
E = Central Heating Return  
F = Safety Valve  
CENTRAL HEATING  
Detailed recommendations are given in BS 6798:1987 and BS 5449-1:1990,  
the following notes are given for general guidance.  
7
PIPE WORK:  
Copper tubing to BS EN 1057:1996 is recommended for water pipes.  
Jointing should be either with capillary soldered or compression fittings.  
Where possible pipes should have a gradient to ensure air is carried  
naturally to air release points and water flows naturally to drain taps.  
The appliance has a built-in automatic air release valve, however it should  
be ensured as far as possible that the appliance heat exchanger is not a  
natural collecting point for air.  
Except where providing useful heat, pipes should be insulated to prevent  
heat loss and avoid freezing.  
Particular attention should be paid to pipes passing through ventilated  
spaces in roofs and under floors.  
BY-PASS:  
The appliance includes an automatic by-pass valve, which protects the main  
heat exchanger in case of reduced or interrupted water circulation through  
the heating system, due to the closing of thermostatic valves or cock-type  
valves within the system.  
SYSTEM DESIGN:  
This boiler is suitable only for sealed systems.  
Drain Cocks:  
These must be located in accessible positions to permit the draining of the  
whole system. The taps must be at least 15mm nominal size and  
manufactured in accordance with BS 2870:1980.  
SAFETY VALVE DISCHARGE:  
The discharge should terminate facing downward on the exterior of the  
building in a position where discharging (possibly boiling water & steam) will  
not create danger or nuisance, but in an easily visible position, and not  
cause damage to electrical components and wiring.  
The discharge must not be over an entrance or a window or any other type  
of public access.  
AIR RELEASE POINTS:  
These must be fitted at all high points where air naturally collects and must  
be sited to facilitate complete filling of the system.  
The appliance has an integral sealed expansion vessel to accommodate the  
increase of water value when the system is heated.  
It can accept up to 6 l (1.3 gal) of expansion water. If the heating circuit has  
an unusually high water content, calculate the total expansion and add an  
additional sealed expansion vessel with adequate capacity.  
MAINS WATER FEED - CENTRAL HEATING:  
There must be no direct connection to the mains water supply even through  
a non-return valve, without the approval of the Local Water Authority.  
FILLING:  
A temporary method for initially filling the system and replacing lost water  
during servicing in accordance with Water Supply Byelaw 14 must be  
provided.  
DOMESTIC WATER  
The domestic water must be in accordance with the relevant  
recommendation of BS 5546:1990. Copper tubing to BS EN 1057:1996 is  
recommended for water carrying pipe work and must be used for pipe work  
carrying drinking water.  
RESIDUAL HEAD OF THE BOILER  
VR003A  
8
FLUE SYSTEM  
2.9 FLUE CONNECTIONS  
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 steamingmust be considered.  
If the terminal is less than 2 metres above a balcony, above ground or above  
a flat roof to which people have access, then a suitable terminal guard must  
be fitted. When ordering a terminal guard, quote the appliance model  
number.  
A suitable terminal guard is available from:  
TOWER FLUE COMPONENTS  
Morley Road  
Tonbridge  
Kent TN9 1RA  
The minimum acceptable spacing from the terminal to obstructions and  
ventilation openings are specified in FIG. 2.6.  
TERMINAL POSTION  
mm  
A - Directly below an open window or other opening  
B - Below gutters, solid pipes or drain pipes  
C - Below eaves  
D - Below balconies or car-port roof  
E - From vertical drain pipes and soil pipes  
F - From internal or external corners  
G - Above ground or below balcony level  
H - From a surface facing a terminal  
I - From a terminal facing a terminal  
J - From an opening in the car port  
300  
75  
200  
200  
75  
300  
300  
600  
1200  
BC  
F
G
F
D
J
HI  
A
E
(e.g. door, window) into dwelling  
K - Vertically from a terminal in the same wall  
L - Horizontally from a terminal in the same wall  
1200  
1500  
300  
K
L
G
FU010A  
FIG. 2.6  
The boiler is designed to be connected to a coaxial flue discharge system.  
Ø 60/100 mm  
FU025A  
FU002A  
FIG. 2.7  
9
In addition, it is also possible to use a split (twin pipe)  
system by fitting a special adaptor to the flue connector  
and using the aperture for the air vent intake located on  
the top part of the combustion chamber.  
To utilise the air intake it is necessary to:  
1. Remove the bottom of the air intake by cutting it with a  
suitable knife (see FIG. 2.8);  
2. Insert the elbow into the air intake until it reaches the  
lower end. (There is no need to use gaskets or sealing  
componds).  
The components marked * in FIG 2.9 are present or absent  
depending on the type of flue system used by the installer.  
FIG. 2.8  
FU05A  
Ø 80 mm  
FU004A  
FU006A  
FIG. 2.9  
IMPORTANT!  
COAXIAL SYSTEMS  
For all flue systems, a restrictor  
must always be inserted into the  
boilers flue connector; the  
restrictor must be ø 43 or ø 41 in  
diameter depending on the length  
of piping indicated in Table 2.1.  
The diagrams illustrate some of the  
various designs for coaxial or twin  
pipe flue systems.  
For further information on  
discharge/ventilation accessories,  
see the FLUE PIPE ACCESSORIES  
MANUAL.  
FIG. 2.10  
FU001A  
10  
TABLE 2.1  
23 MFFI  
Exhaust  
Type  
Restrictor  
ø 43 mm  
NO  
Restrictor  
Maximum  
Extension  
Exhaust/Air  
Risk of Condensation Forming  
Piping not insulated  
Piping insulated  
ø 43 restrictor NO  
ø 43 restrictor NO  
C12 (xx)  
C32 (xx)  
C42 (xx)  
Coaxial  
Systems  
ø 60/100  
L min = 0.5 m  
L max = 2 m  
L min = 2 m  
L max = 4 m  
L = 4 m  
NONE  
NONE  
NONE  
NONE  
Exhaust  
Type  
Restrictor  
ø 43 mm  
NO  
Restrictor  
Maximum  
Extension  
Exhaust/Air  
Risk of Condensation Forming  
Piping insulated  
Piping not insulated  
ø 43 restrictor NO  
ø 43 restrictor NO  
C12 (xy)  
C32 (xy)  
C42 (xy)  
43 m  
43 m  
43 m  
L max = 11.5 m  
L min = 11.5 m  
L max = 43 m  
NONE  
5,7 m  
NONE  
21,7 m  
4.3 m  
4.3 m  
6.9 m  
6.9 m  
Twin Pipe  
Systems  
ø 80/80  
C52 (xy) L max = 11,4 m L min = 11,4 m  
C82 (xy)  
L max = 40m  
40 m  
27 MFFI  
Exhaust  
Type  
Restrictor  
ø 41 mm  
Maximum  
NO Restrictor Extension  
Exhaust/Air  
Risk of Condensation Forming  
Piping not insulated  
Piping insulated  
ø 41 restrictor NO restrictor ø 41 restrictor NO restrictor  
C12 (xx)  
C32 (xx)  
C42 (xx)  
Coaxial  
Systems  
ø 60/100  
L min = 0.5 m  
L max = 1 m  
L min = 1 m  
L max = 4 m  
L = 4 m  
NONE  
NONE  
NONE  
NONE  
Exhaust  
Type  
Restrictor  
ø 41 mm  
Maximum  
NO Restrictor Extension  
Exhaust/Air  
Risk of Condensation Forming  
Piping insulated  
Piping not insulated  
ø 41 restrictor NO restrictor  
ø 41 restrictor NO restrictor  
C12 (xy)  
C32 (xy)  
C42 (xy)  
62 m  
L max = 38 m  
L max = 34 m  
L min = 38 m  
L max = 62 m  
62 m  
62 m  
19 m  
19 m  
31 m  
31 m  
8 m  
8 m  
11 m  
11 m  
Twin Pipe  
Systems  
ø 80/80  
C52 (xy)  
C82 (xy)  
L min = 34 m  
L max = 54 m  
54 m  
L = Sum of the total length of exhaust + air intake piping.  
11  
In calculating the lengths of the pipes, the  
maximum length Lmust also take into  
consideration the values for the  
exhaust/air intake end terminals, as well  
as 90° elbows for coaxial systems.  
The C52 types must comply with the  
following requirements:  
TWIN PIPE  
SYSTEMS  
1 - The exhaust/ air intake pipes must  
have the same diameter of ø 80 mm.  
2 - If elbows are to be inserted into the  
air intake and/or exhaust system, the  
calculation of the overall length must  
take into consideration the values for  
each elbow, see the FLUE PIPE  
ACCESSORIES MANUAL.  
3 - The exhaust pipe must protrude by at  
least 0.5 m above the top of the roof  
in the event that it is located on the  
opposite side to the side with the air  
intake (this condition is not obligatory  
when the air intake and exhaust are  
located on the same side of the  
building).  
FIG. 2.11  
FU007A  
To connect a room thermostat, it is necessary to:  
2.10 ROOM THERMOSTAT  
CONNECTION  
1. - Open the control panel as indicated in section 3.3.  
2.- Remove the link Afrom the terminal block on the reverse of the control panel.  
3. - Insert the thermostat cable through the cable grommet and fasten it by means of the  
cable-clamp provided.  
4. - Then connect the thermostat wires to the terminal block.  
5.- If a remote time clock is to be fitted, disconnect the integral time clock from the P.C.B.  
6. - Using a volt-free switching time clock, connect the switching wires from the time clock  
following points 1-4 above.  
7. - If using an external time clock and room thermostat, these must be connected in  
series as points 1-7 above.  
Note: Only a two-wire type room thermostat can be used.  
An anti-frost device is built-in to the appliances electronic regulation  
system.  
A
Fo017A  
Fo016A  
12  
2.12 ELECTRICAL DIAGRAM  
A01  
A02  
A03  
A04  
A05  
A06  
A07  
A08  
A09  
A10  
A11  
A12  
A13  
A14  
=
=
=
=
=
=
=
=
=
=
=
=
=
=
Circulation Pump  
Fan  
LEGEND:  
Spark Generator/Gas Valve Supply  
Motorised Diverter Valve  
Flame Detection Circuit  
Detection Electrode  
Main Circuit Temperature Probe  
Domestic Hot Water Temperature Probe  
Domestic Hot Water Flow Switch  
Main Circuit Flow Switch  
Modulator  
A
B
=
=
Time Clock Connector  
Central Heating Selection (Winter) and  
Temperature Adjustment  
Connector for Total Check System  
Domestic Hot Water Temperature Adjustment  
Soft-light Adjustment  
C
D
E
F
G
H
I
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
Maximum Heating Adjustment  
On/Off Switch  
On/Off L.E.D.  
Fume Sensor L.E.D.  
Air Pressure Switch  
Safety Thermostat  
External (Room) Thermostat  
J
K
L
Ignition Failure (Lockout) L.E.D.  
Low System Water Level/Lack of Circulation L.E.D.  
Reset Button  
M
N
O
P
Q
R
S
T
V
U
Economy/Comfort Selector  
Overheat L.E.D.  
Temperature L.E.D.s  
Transformer  
Circulation Pump Relay  
Fan Relay  
Gas Valve Relay  
Motorised Diverter Valve Relay  
Spark Generator  
Colours:  
Gry  
Wh  
Pnk  
Brn  
=
=
=
=
=
=
Grey  
White  
Pink  
Brown  
Blue  
Bl  
Blk  
Black  
Rd/Blk = Red/Black  
Anti-cycling Device Adjustment for Heating  
J
K
FIG. 2.12  
SE017A  
13  
FIG. 2.13  
N
O
R
T
Q
S
J
U
K
L
M
SF014A  
2.13 WATER CIRCUIT DIAGRAM  
FIG. 2.14  
LEGEND:  
1. Fan  
2. Main Heat Exchanger  
3. Overheat Thermostat  
4. Burner  
5. Ignition Electrodes  
6. Detection Electrode  
7. Motorised Valve  
8. Main Circuit Temperature Probe  
9. Main Circuit Flow Switch  
10. Automatic By-pass  
11. Domestic Hot Water Temperature Probe  
12. Secondary Heat Exchanger  
13. Gas Valve  
14. Domestic Hot Water Flow Switch  
15. Domestic Water Inlet Filter  
16. Pressure Gauge  
17. Safety Valve  
18. Circulation Pump with Automatic  
Air Release Valve  
19. Expansion Vessel  
20. Air Pressure Switch  
A. Central Heating Flow  
B. Domestic Hot Water Outlet  
C. Inlet Gas  
D. Domestic Cold Water Inlet  
E. Central Heating Return  
SI017A  
14  
3.  
COMMISSIONING  
MTS (GB) Limited support the  
you will find a copy of the  
initiative. Within the information pack  
logbook. It is important that this is  
3.1  
INITIAL PREPARATION  
completed in the presence of your customer, they are shown how to us it,  
and it is signed by them. Please instruct your customer that they must have  
their  
logbook with them whenever they contact a service engineer  
or us.  
Preliminary electrical system checks to ensure electrical safety must be  
carried out by a competent person i.e. polarity, earth continuity, resistance to  
earth and short circuit.  
FILLING THE HEATING SYSTEM:  
Remove the panels of the case and lower the control panel (see section  
3.3 for further information).  
Open the central heating flow and return cocks supplied with the  
connection kit.  
Unscrew the cap on the automatic air release valve one full turn and leave  
open permanently.  
Close all air release valves on the central heating system.  
Gradually open valve(s) at the filling point (filling-loop) connection to the  
central heating system until water is heard to flow, do not open fully.  
Open each air release tap starting with the lower point and close it only  
when clear water, free of air, is visible.  
Purge the air from the pump by unscrewing anticlockwise the pump  
plug and also 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.  
FILLING OF THE D.H.W. SYSTEM:  
Close all hot water draw-off taps.  
Open the cold water inlet cock supplied with the connection kit.  
Open slowly each draw-off tap and close it only when clear water, free of  
bubbles, is visible  
GAS SUPPLY:  
Inspect the entire installation including the gas meter, test for soundness  
and purge, all as described in BS 6891:1988.  
Open the gas cock (supplied with the connection kit) to the appliance and  
check the gas connector on the appliance for leaks.  
When the installation and filling are completed turn on the central heating  
system (section 3.4) and run it until the temperature has reached the boiler  
operating temperature. The system must then be immediately flushed  
through.  
The flushing procedure must be in line with BS 7593:1992 code of practice  
for treatment of water in domestic hot water central heating systems.  
During this operation, we highly recommend the use of a central heating  
flushing 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.  
15  
3.2  
CONTROL PANEL  
LEGEND:  
A - On/Off knob  
B - Domestic hot water temperature adjustment knob  
C - Central heating selection (winter) and temperature  
adjustment knob  
D - On/Off L.E.D. (green)  
E - Fume sensor L.E.D. (yellow)  
F - Ignition failure (lockout) L.E.D. (red)  
G - Economy/Comfortmode selection knob  
H - Ignition failure (lockout) and/or overheat reset button  
I
- Overheat L.E.D. (red)  
J - Low system water level L.E.D. (red)  
K - Central heating temperature L.E.D (yellow)  
L - Time clock  
FIG. 3.1  
M - Heating system pressure gauge  
In order to access the inside of the boiler, it is necessary to unscrew  
the fastening screws Aof the control panel located on the lower part  
of the panel itself.  
The control panel moves downward and when pulled forward rotates  
on two lateral hinges.  
3.3  
1
REMOVING THE  
FRONT PANEL  
The panel stays in a semi-horizontal position, which allows access to  
the inner parts of the boiler.  
In order to increase the maneuvering space, it is possible to raise the  
control panel and rotate it to a fully horizontal position.  
A
4
FO006A  
FO012A  
FO013A  
2
B
FO009A  
To dismantle the front  
casing panel it is necessary  
to:  
1 - Remove the two screws  
B;  
2 - Lift the front casing panel  
up and forward.  
5
3
FO008A  
16  
THE CHECKS TO BE RUN BEFORE INITIAL START-UP ARE AS FOLLOWS:  
1. Make sure that:  
3.4. INITIAL START-UP  
-the screw on the automatic air valve has been loosened when the  
system is full;  
- If the water pressure in the system is below 1 bar, bring it up to the  
appropriate level;  
-Check to see whether the gas cock is closed;  
-Make sure that the electrical connection has been made properly and  
that the earth wire is connected to an efficient earthing system;  
- Supply power to the boiler by turning the On/Off switch A(see FIG.3.1)  
- the L.E.D. Dwill illuminate - turn the selector knob Cto the winter  
/central heating position. This will start the circulation pump. After 7  
seconds, the boiler will signal a shutdown due to ignition failure. Leave  
the boiler as it is until all of the air has been bled from the lines.  
-Loosen the cap on the head of the pump to eliminate any air pockets;  
-Repeat the procedure for bleeding the radiators of air;  
-Open the taps for a brief period;  
-Check the system pressure and, if it has dropped, open the filling loop  
again to bring the pressure back up to 1 bar.  
2. Check the exhaust flue for the fumes produced by combustion.  
3. Make sure that all gate valves are open;  
4. Turn on the gas cock and check the seals on the connections, including  
the one for the burner, making sure that the meter does not signal the  
passage of gas. Check the connections with a soap solution and  
eliminate any leaks.  
5. Press the reset button Afor the lighting system; the spark will light the  
main burner. If the burner does not light the first time, repeat the  
procedure.  
6. Check the minimum and maximum pressure values for the gas going to  
the burner; adjust it if needed using the values indicated in the table in  
section 4 (See the relative section for burner pressure adjustment within  
the servicing manual).  
(See section 3.2 for references) it is possible to:  
3.5  
OPERATIONAL  
ADJUSTMENTS  
-
-
-
Set the temperature of the heating system by adjusting the knob C”  
Set the temperature of the domestic hot water by turning knob B”  
The selector knob Gallows the user to choose the economy mode  
(position E) or the comfort mode (position C).  
The economy mode is the normal state for the operation of the boiler,  
since the domestic water is heated up only when a tap is turned on.  
The comfort mode is a special operating state, because the water  
contained in the secondary exchanger and in the primary exchanger is  
kept in a preheated condition, thereby allowing a quicker delivery of  
domestic water when required. The latter is therefore the more  
convenient choice.  
To access the areas in which adjustments are made, it is necessary to open  
the control panel, as indicated in section 3.3, then remove the rear  
inspection cover by unscrewing the two screws. Access is thereby provided  
to the P.C.B. and to the following components:  
1. the power supply cable connector;  
2. the fuses;  
3. the soft-light potentiometer the setting for which can range from the  
minimum thermal power to the maximum;  
4. the maximum thermal heating power potentiometer adjustable by the  
minimum to maximum power (already calibrated in the factory to 70% of  
the maximum thermal power);  
5. the potentiometer for adjusting the ignition delay (anti-cycling) feature,  
which can be set from 0 to 2 minutes (set in the factory at one minute);  
6. the time clock connector.  
17  
The flue connector has two apertures, readings can be  
taken for the temperature of the combustion by-products  
and of the combustion air, as well as of the concentrations  
3.6  
COMBUSTION ANALYSIS  
2
2
of O and CO , etc. .  
To access these intakes it is necessary to unscrew the front  
screw and remove the metal plate with sealing gasket.  
The best test conditions, with the maximum heating power,  
are achieved by turning the selector knob Cto the max”  
position and removing the electrical connection to the heating  
sensor (see section 6.).  
FU008A  
3.7  
FUME DISCHARGE  
MONITORING  
In the boiler, it is possible to monitor the correct operation of  
the flue exhaust/air intake, checking for a loss of general  
pressure in the system. Through the use of a differential  
manometer connected to the test points of the combustion  
chamber, it is possible to detect the P of operation of the air  
pressure switch.  
The value detected should not be less than 0,55 mbar for  
23kW and 0.75 mbar for 27kW under conditions of maximum  
thermal power in order for the boiler to function properly and  
without interruption.  
FU009A  
The boiler is fitted with the following devices (see section 3.2 for references).  
1 - IGNITION FAILURE:  
3.8  
BOILER SAFETY SYSTEMS  
This control signals an ignition failure on the burner 7 seconds after a  
lighting failure. The L.E.D. Fwill illuminate to signal the shutdown  
status.  
The system can be reset by pressing and releasing the button Hafter  
checking to make sure that the gas cock is open.  
2 - CIRCULATION FAILURE:  
This control signals that the safety pressure switch on the primary  
circuit has not sensed a pressure of at least 1 bar within 40 seconds of  
the activation of the circulation pump; the circulation pump comes to a  
halt and the red L.E.D. Jilluminates.  
The system may be reset, after re-establishing the correct level of  
pressure in the boiler, turning the Aknob.  
3 - OVERHEATING:  
This control shuts off the boiler in the case where the primary circuit  
reaches a temperature in excess of 105°C.  
The red L.E.D.s Iand Fwill illuminate to signal this shutdown  
status.  
The system can be reset by waiting a few minutes for the primary  
exchanger to cool down and then by pressing and releasing the H”  
button.  
4. LIMESCALE BUILD-UP:  
The boiler is equipped with a device that limits the formation of  
Limescale in the secondary exchanger by controlling the temperature of  
the domestic hot water (max 61°C) and also controlling the temperature  
of the water in the primary heating circuit.  
18  
5. ANTI-FROST DEVICE:  
The boiler is equipped with a device that, in the event of the water  
temperature going below 5°C, the 3-way diverter valve switches to  
domestic hot water and the burner ignites at the minimum power until  
the boiler water reaches a temperature of about 50°C.  
This device operates only if the boiler is functioning perfectly and:  
- the system pressure is sufficient;  
- the boiler is powered electrically;  
- the gas is distributed.  
6 - EXHAUST DISCHARGE ANOMALY SHUTDOWN:  
The boiler is fitted with safety devices, which in the event of defective  
discharge of exhaust fumes, automatically interrupts the gas supply,  
thereby shutting off the boiler.  
The shutdown of the boiler is temporary and is indicated by the  
illumination of the yellow L.E.D. Efor a period of about 15 minutes.  
Once this time period has passed and the discharge state of exhaust  
fumes has returned to normal, the boiler automatically turns back on.  
7 - SAFETY SHUTDOWN:  
At the start of every lighting phase, the P.C.B. performs a series of  
internal controls. If a malfunction occurs, the boiler will shutdown until  
the problem has been resolved.  
DRAINING THE HEATING SYSTEM  
The heating system must be emptied as follows:  
3.9  
DRAINING THE SYSTEM  
- Turn off the boiler;  
- Open the drain valve for the system and place a container below to catch the  
water that comes out;  
- Empty the system at the lowest points (where present). If you plan on not  
using the heating system for an extended period of time, it is recommended  
that you add antifreeze with an ethylene glycol base to the water in the  
heating lines and radiators if the ambient temperature drops below 0°C during  
the winter.  
This makes repeated draining of the entire system unnecessary.  
DRAINING THE DOMESTIC HOT WATER SYSTEM  
Whenever there is the danger of the temperature dropping below the freezing  
point, the domestic hot water system must be drained as follows:  
- Turn off the general water valve for the household plumbing system;  
- Turn on all the hot and cold water taps;  
- Empty the remaining water from the lowest points in the system (where  
present).  
19  
4.  
GAS ADJUSTMENTS  
Liquid Butane Gas Liquid Propane Gas  
CATEGORY II2H3+  
Methane Gas  
G20  
G30  
G31  
3
Lower Wobbe Index (15°C;1013mbar)  
Nominal Delivery Pressure  
Minimum Delivery Pressure  
MJ/m h  
mbar  
mbar  
45.67  
20  
17  
80.58  
29  
20  
80.58  
37  
25  
23 MFFI  
Main Burner: n. 13 jets (ø)  
Consumption (15°C; 1013mbar)  
Consumption (15°C; 1013mbar)  
Gas Cock Outlet Pressure  
max - min  
mm  
mc/h  
Kg/h  
1.30  
2.72  
----  
0.77  
----  
2.02  
0.77  
----  
2.02  
mbar  
11.0 - 2.0  
(*) - 6.0  
(*) - 6.0  
27 MFFI  
Main Burner: n. 15 jets (ø)  
Consumption (15°C; 1013mbar)  
Consumption (15°C; 1013mbar)  
Gas Cock Outlet Pressure:  
max - min  
1.30  
3.15  
----  
0.77  
----  
2.34  
0.77  
----  
2.31  
mc/h  
Kg/h  
mbar  
11.0 - 1.6  
(*) - 4.6  
(*) - 6.0  
[1 mbar = 10,197 mmc.a.]  
The outlet pressure of the gas cock is obtained by completely loosening the  
screw on the solenoid. The maximum pressure of the gas to the burner will  
be equal to the nominal delivery pressure minus the head loss within the  
gas valve.  
The boiler can be converted to use either methane (natural) gas (G20)  
or LPG (G30 - G31) by an Authorised Service Centre.  
The operations that must be performed are the following:  
1. Replace the jets on the main burner (see table in section 4);  
2. Adjust the maximum and minimum thermal capacity values for the boiler  
(see table in section 4);  
4.1  
CHANGING THE  
TYPE OF GAS  
3. Replace the gas rating plate;  
4. Adjust the maximum thermal power setting;  
5. Adjust the soft-light feature;  
6. Adjust the ignition delay feature for the heating system (can be set from 0  
to 2 mins.).  
Methane  
Gas  
Liquid  
Butane  
Gas  
Liquid  
Propane  
Gas  
CATEGORY II2H3+  
G20  
G30  
G31  
Recommended Soft-  
light Pressure  
(mbar)  
8.0  
16.0  
16.0  
20  
It is recommended that the following inspections be carried out on the  
boiler at least once a year:  
5.  
MAINTENANCE  
1 - Check the seals for the water connections; replacement of any faulty  
seals.  
2 - Check the gas seals; replacement of any faulty gas seals.  
3 - Visual check of the entire unit.  
4 - Visual check of the combustion process or analysis of combustion by-  
products (see section 3.6) and cleaning of the burner if needed.  
5 - If called for by point. 3, dismantling and cleaning of the combustion  
chamber.  
6 - If called for by point. 4, dismantling and cleaning of the burner jets.  
7 - Visual check of the primary heat exchanger:  
-
-
check for overheating in the blade assembly;  
clean the exhaust fan if needed.  
8 - Adjustment of the flow rate of the gas: flow rate for lighting, partial load  
and full load.  
9 - Check of the heating safety systems:  
-
-
safety device for maximum temperature;  
safety device for maximum pressure.  
10- Check of the gas safety systems:  
-
safety device for lack of gas or flame ionisation (detection  
electrode);  
-
safety device for gas cock.  
11- Check of the electrical connection (make sure it complies with the  
instructions in the manual).  
12- Check of domestic hot water production efficiency (flow rate and  
temperature)  
13- General check of the combustion by-products of the  
discharge/ventilation system.  
14- Check of the general performance of the unit.  
21  
7.  
MISCELLANEOUS  
7.1  
WIRING DIAGRAM FOR  
TWO HEATING ZONES  
BROWN  
BLUE  
5
2
BOILER ELECTRICAL SUPPLY CABLE  
GREY  
9
ORANGE  
10  
3
Remove internal time clock plug  
from the the P.C.B. then connect  
room stat terminal block on the  
reverse of the boiler control panel  
(see section 2.10) to 9 + 10 on  
the junction box.  
GREEN/YELLOW  
V4043H  
VALVE  
TYPICAL  
JUNCTION BOX  
1  
2  
3  
4  
5  
6  
7  
8  
9  
10  
1
3
2
4
5
2
T6360B  
ROOM  
THERMOSTAT  
ZONE1  
BROWN  
BLUE  
8
2
9
GREY  
ORANGE  
10  
3
GREEN/YELLOW  
V4043H  
VALVE  
1
3
2
6
8
2
T6360B  
ROOM  
THERMOSTAT  
ZONE 2  
L
N
E
1
2
3
If a room thermostat is not requied on Zone 1, insert a link  
between 4 + 5 on the junction box.  
If a room thermostat is not requied on Zone 2, insert a link  
between 6 + 8 on the junction box.  
240V  
MAINS INPUT (3 AMP)  
SH010A  
22  
7.2  
WIRING DIAGRAM FOR  
CONNECTION TO AN  
ARISTON UNVENTED  
CYLINDER  
1
3
2
4
5
2
BOILER ELECTRICAL SUPPLY CABLE  
Remove internal time clock plug  
from the the P.C.B. then connect  
room stat terminal block on the  
reverse of the boiler control panel  
(see section 2.10) to 9 + 10 on  
the junction box.  
T6360B  
ROOM  
THERMOSTAT  
TYPICAL  
JUNCTION BOX  
BROWN  
BLUE  
5
2
9
1  
2  
3  
4  
5  
6  
7  
8  
9  
10  
GREY  
ORANGE  
10  
3
GREEN/YELLOW  
V4043H  
HEATING VALVE  
BROWN  
BLUE  
8
2
GREY  
9
ORANGE  
10  
3
GREEN/YELLOW  
V4043H  
HOT WATER VALVE  
L
N
E
1
2
3
240V  
MAINS INPUT (3 AMP)  
Cylinder  
thermostat  
1
8
6
1
Thermal  
C/P  
cut-out  
P
2
1 C/P  
2
Not  
used  
SH009A  
23  
7.  
TECHNICAL INFORMATION  
27 MFFI  
23 MFFI  
CE Certification  
63AU4549  
63AU4549  
Heat Input  
max/min kW  
25.6/11.0  
29.8/12.0  
Heat Output  
max/min kW  
Efficiency of Nominal Heat Input  
Efficiency at 30% of Nominal Heat Input  
Heat Loss to the Casing (T=50°C)  
Flue Heat Loss with Burner Operating  
Flue Heat Loss with Burner Off  
Maximum Discharge of Fumes (G20)  
Residual Discharge Head  
%
%
%
%
%
Kg/h  
mbar  
92.9  
91.1  
1.0  
6.1  
0.4  
93.5  
90.7  
0.2  
6.3  
0.4  
49.5  
0.96  
60  
1.60  
3
Consumption at Nominal Capacity(G20)  
m /h  
2.72  
3.15  
3
Gas Consumption after 10 Minutes*  
(15°C, 1013 mbar) (G30-G31)  
m
0.32/0.39  
2.02/2.00  
123  
0.37  
2.34/2.31  
128.8  
Kg/h  
Temp. of exhaust fumes at nominal capacity °C  
2
CO Content  
%
7.2  
6.9  
2
O Content  
%
7.5  
8.1  
CO Content  
Minimum Ambient Temperature  
ppm  
°C  
51.9  
+5  
48  
+5  
Head Loss on Water Side (max) (T=20°C) mbar  
200  
200  
Residual Head of System  
bar  
0.25  
82/42  
56/36  
9.7  
2.2  
2.6  
8/0.2  
6
1
130  
3
0.25  
82/42  
56/36  
11.4  
2.6  
2.6  
8/0.2  
6
Heating Temperature  
max/min °C  
Domestic Hot Water Temperature  
D.H.W. Flow Rate T=35°C  
D.H.W. Flow Rate T=35°C  
D.H.W. Minimum Flow Rate  
Pressure of Domestic Hot Water  
Expansion Vessel Capacity  
Expansion Vessel Pre-load Pressure  
Maximum Water Content of System  
Maximum Heating Pressure  
max/min °C  
l/min  
gal/min  
l/min  
max/min bar  
l
bar  
l
bar  
1
130  
3
Nominal Pressure  
Natural Gas (G20) mbar  
20  
20  
LPG (G30-G31)  
mbar  
V/Hz  
W
30-37  
230 / 50  
140  
30-37  
230 / 50  
155  
Electrical Supply  
Power Consumption  
Protection Grade of Electrical System  
Internal Fuse Rating  
Weight  
IP  
X4D  
FAST 2 AT  
38  
X4D  
FAST 2 AT  
39  
Kg  
G.C. Number  
47-116-14  
47-116-15  
*Calculated at 70% maximum output  
Manufacturer:  
Merloni TermoSanitari SpA - Italy  
Commercial subsidiary: MTS (GB) LIMITED  
MTS Building  
Hughenden Avenue  
High Wycombe  
Bucks HP13 5FT  
Telephone: (01494) 755600  
Fax: (01494) 459775  
Technical Service Hot Line: (01494) 539579  
Servicing  
Instructions  
Type C Boilers  
G.C.N: 47-116-14  
47-116-15  
LEAVE THESE INSTRUCTIONS  
WITH THE END-USER  
Country of destination: GB  
1.  
SERVICING INSTRUCTIONS  
TABLE OF CONTENTS  
1.1  
1.2  
REPLACEMENT OF PARTS  
TO GAIN GENERAL ACCESS  
- Removing the front panel  
- Removing the sealed chamber frontal cover  
- Removing the side panels  
1.3  
ACCESS TO THE COMBUSTION CHAMBER  
- Removing the combustion cover  
- Removing the burner and jets  
- Removing the electrodes  
- Removing the main heat exchanger  
- Removing the air pressure switch  
- Removing the fan  
- Removing the venturi device  
1.4  
1.5  
SERVICING AND REMOVAL OF THE GAS VALVE  
- Setting the gas pressures  
- Removing the spark generator  
- Removing the gas valve  
ACCESS 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 pump  
- Removing the pressure gauge  
- Removing the expansion vessel  
- Removing the overheat thermostat  
- Removing the heating temperature sensor (N.T.C.)  
- Removing the D.H.W. temperature sensor (N.T.C.)  
- Removing the divertor valve actuator  
- Removing the D.H.W. flow switch  
1.6  
ACCESS TO THE CONTROL SYSTEM  
- Checking the fuses  
- Removing the time clock  
- Removing the P.C.B.  
2.  
2.1  
3.  
4.  
FAULT FINDING  
FAULT FINDING GUIDE (FLOW-CHART)  
ELECTRICAL DIAGRAMS  
SHORT SPARE PARTS LIST  
B063  
2
2. The control panel moves downward and when pulled forward,  
rotates on two lateral hinges; the panel stays in a semi-  
horizontal position, which allows access to the inner parts of  
the boiler (FIG. 1.2);  
3. In order to increase the manouvering space, it is possible to  
raise the control panel and rotate it to a fully horizontal position  
(FIG. 1.3);  
4. Remove the screws “B” from the front panel bottom lip  
(FIG. 1.4);  
5. Lift the front panel from the raised screws at the the top of the  
casing (FIG. 1.5).  
1.  
SERVICING INSTRUCTIONS  
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 further details).  
After servicing, preliminary electrical system checks must be  
carried out to ensure electrical safety (i.e. polarity, earth continuity,  
resistance to earth and short circuit).  
FIG. 1.4  
1.1  
REPLACEMENT OF PARTS  
The life of individual components varies and they will need  
servicing or replacing as and when faults develop.  
B
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.  
1.2  
TO GAIN GENERAL ACCESS  
FO016A/15.eps  
All testing and maintenance operations on the boiler require the  
control panel to be lowered. This will also require the removal of  
the casing.  
Removing the front panel  
1. Loosen the fastening screws Aof the control panel located on  
the lower part of the panel itself. (FIG. 1.1);  
FIG. 1.1  
A
19.eps  
FIG. 1.5  
16.eps  
FIG. 1.2  
14.eps  
13.eps  
FIG. 1.3  
B063  
3
Removing the sealed chamber frontal cover  
Removing the side panels  
1. Remove the screws C(FIG. 1.6);  
2. Lift the sealed chamber frontal cover from the locating pins  
(FIG. 1.7).  
1. Remove the four screws Dfor each side panel (FIG.1.8);  
2. Pull the panel away from the boiler, then lift the panel up and  
remove from the boiler (FIG.1.9).  
FIG. 1.8  
D
D
C
C
D
98.tif  
18.eps  
FIG. 1.6  
FIG. 1.9  
FIG. 1.7  
17 eps  
97.tif  
B063  
4
1.3  
ACCESS TO THE COMBUSTION CHAMBER  
Removing the combustion cover  
1. Remove the screws E(FIG. 1.10);  
2. Lift off the combustion cover.  
78 eps  
Fig. 1.12  
Removing the electrodes  
Before carrying out this procedure, unscrew and slide the  
burner forward (see previous section).  
E
E
1. Remove rubber gasket G(Fig. 1.13);  
E
2. To remove the detection electrode disconnect the cable  
at its connection point close to the P.C.B. (Fig. 1.14);  
FIG. 1.13  
99.tif  
FIG. 1.10  
G
Removing the burner and jets  
1. Remove the screws Ffrom the burner (FIG. 1.11);  
2. Remove the burner (FIG. 1.12);  
3. Remove the jets using a No. 7 socket spanner;  
4. Replace in reverse order.  
49 eps  
FIG. 1.11  
F
F
12 eps  
50 eps  
FIG. 1.14  
B063  
5
3. Remove screw H(FIG. 1.15);  
Removing the main heat exchanger  
4. Gently slide the electrode downward (FIG. 1.16).  
1. Drain the boiler of water;  
2. Release the overheat thermostat sensor I(FIG. 1.17);  
3. Release the two connection nuts Jconnecting the  
exchanger to the flow and return pipes (FIG. 1.18);  
4. Pull it straight out (FIG. 1.19).  
FIG. 1.15  
H
I
51 eps  
Fig. 1.17  
75 eps  
11 eps  
J
76 eps  
FIG. 1.18  
52 eps  
FIG. 1.16  
To replace, repeat the steps in reverse order, paying  
particular attention to the following:  
a -Centre the electrode in the positioning hole carefully,  
otherwise the electrode may break;  
FIG. 1.19  
6 eps  
b -Check that the cables have been connected correctly;  
c -Check that the rubber gasket covers the cable/ electrode  
connection point completely.  
B063  
6
Removing the air pressure switch  
Removing the fan  
1. Disconnect the electrical connections Kand silicon pipes  
Lfrom their connection points (FIG. 1.20);  
2. Remove screws Mon the top of the sealed chamber  
(FIG. 1.21);  
1. Disconnect electrical connections Nand silicon pipes  
O(FIG.1.23);  
2. Remove screw Pand remove the fan collar clamp Q”  
(FIG.1.24);  
3. Unscrew to remove switch from the plate (FIG. 1.22).  
3. Remove screws R(FIG.1.25);  
4. Remove fan and mounting plate (FIG.1.26).  
FIG. 1.20  
FIG. 1.23  
K
N
N
L
O
90.tif  
93.tif  
FIG. 1.21  
Q
P
M
FIG. 1.24  
94.tif  
M
R
R
91.tif  
FIG. 1.25  
95.tif  
FIG. 1.22  
FIG. 1.26  
96.tif  
B063  
7
1.4  
SERVICING AND REMOVAL  
OF THE GAS VALVE  
Setting the minimum and the maximum power of the boiler  
1. Check that the supply pressure to the gas valve is a minimum of 20 mbar  
for natural gas.  
Setting the gas pressures  
2. To do this, remove the screw “A”.  
1
Fit the pipe of the pressure gauge to the pressure connection of the gas  
valve B.  
When you have completed this operation, replace the screw Asecurely  
into its housing to seal off the gas.  
3. To check the pressure supplied by the gas valve to the burner, remove the  
screw C. Fit the pipe of the pressure gauge to the pressure outlet of the  
gas valve D.  
Disconnect the compensation pipe either from the gas valve or from the  
sealed chamber.  
4. Set the On/Off button to position < I > and the summer/winterswitch to  
the winter position.  
B
A
To set the maximum power, turn on the hot water tap and allow the hot  
water tap to run at a rate of about 8 litres/minute so that the main burner  
lights.  
Adjust nut Eon the modureg to set the gas pressure (displayed on the  
pressure gauge) corresponding to the maximum power (see TABLE Apage  
9).  
VG001Aa  
2
5. To set the minimum power, disconnect a supply terminal from the modureg  
and adjust screw F.  
D
C
Turn the screw clockwise to increase the pressure and coun-  
ter-clockwise to decrease the pressure (displayed on the  
pressure gauge) corresponding to the minimum power (see TABLE Apage  
9).  
6. When you have completed the above operations, turn off the  
hot water tap, re-connect the supply terminal to the modureg  
on the gas valve and replace the cap on the screw of the  
modureg.  
VG001Ac  
Setting the maximum heating circuit power  
3
7. To set the maximum heating circuit power, place the  
On/Off button to position < I > and the summer/winterswitch to winter  
position.  
Turn the knob of the heating thermostat clockwise to maximum.  
8. Remove the inspection panel of the P.C.B. and fit a small cross-head  
screwdriver in to the right hand potentiometer. Turn clockwise to increase  
the pressure or counter-clockwise to reduce the pressure. Adjust the  
setting to the required heating pressure value (displayed on the pressure  
gauge), as indicated in the diagrams shown in page 10.  
E
9. Turn off the boiler by placing the main switch to the "Off" position.  
Setting pressure for soft ignition.  
VG001Ab  
Disconnect the detection electrode connection from the P.C.B..  
Start the boiler and during the ignition sequence adjust the left hand  
potentiometer until the gas pressure reads the required gas pressure as  
per the table below.  
4
Once the gas pressure is set turn off the boiler and re-connect the  
connection to the P.C.B.  
NB.: It may be necessary to reset the flame failure reset a number of times  
during this operation.  
F
NATURAL GAS (G20)  
BUTANE GAS (G30)  
PROPANE GAS (G31)  
Recommended pressure for  
soft-light ignition  
8 mbar  
16 mbar  
16 mbar  
VG001Ad  
B063  
8
Regulating the heating power for  
natural gas (G20)  
model 23  
model 27  
CG007A  
Regulating the heating power for  
butane gas (G30)  
model 23  
model 27  
CG008A  
Regulating the heating power for  
propane gas (G31)  
40  
38  
36  
34  
model 23  
model 27  
CG009A  
TABLE A”  
2.70  
1.16  
2.01 Kg/h  
2.00 Kg/h  
0.85 Kg/h  
37 mbar  
0.87 Kg/h  
28 mbar  
20  
11.0  
2.0  
27.7 mbar  
6.0 mbar  
35.5 mbar  
7.3 mbar  
12 x 0.77  
12 x 0.77  
3.15  
1.26  
2.34 Kg/h  
0.94 Kg/h  
28 mbar  
2.31 Kg/h  
0.93 Kg/h  
37 mbar  
20  
11.0  
1.6  
27.7 mbar  
4.6 mbar  
35.5 mbar  
6.0 mbar  
14 x 0.77  
14 x 1.30  
14 x 0.77  
TB012A  
B063  
9
Removing the spark generator  
1. Disconnect ignition leads Tby pulling upward  
(FIG. 1.27);  
2. Remove the screw V(FIG. 1.28);  
3. Remove the spark generator (FIG. 1.29).  
61.eps  
T
Soft-light  
Max Heating  
Adjustment Adjustment  
VR015A.eps  
45.eps  
FIG. 1.27  
FIG. 1.28  
FIG. 1.29  
10. Remove the pipe from the pressure gauge and connect  
screw Cto the pressure outlet in order to seal off the  
gas.  
11. Carefully check the pressure outlets for gas leaks (valve  
inlet and outlet).  
IMPORTANT!  
Whenever you disassemble and reassemble the gas  
connections, always check for leaks using a soap and water  
solution.  
V
43.eps  
44.eps  
B063  
10  
Removing the gas valve  
1.6  
ACCESS TO THE WATER CIRCUIT  
1. Disconnect all the cables from the solenoid and  
modureg;  
2. Remove the spark generator (see previous section);  
3. Release the top nut W(FIG. 1.30);  
4. Remove the screws Xfrom the bottom of the gas valve  
pipe (FIG. 1.31);  
Important! Before any component is removed, the boiler  
must be drained of all water.  
Removing the D.H.W. (secondary) exchanger  
1.Remove the screws Y(FIG 1.33 + FIG 1.34);  
2.Push the exchanger towards the rear of the boiler, and lift  
upwards and remove out of the front of the boiler  
(FIG 1.35);  
5. Remove the gas valve (FIG. 1.32).  
3.Before replacing the exchanger ensure that the O-rings  
are in good condition and replace if necessary.  
W
Y
47.eps  
FIG. 1.30  
FIG. 1.33  
22.eps  
X
X
Y
FIG. 1.31  
48.eps  
FIG. 1.34  
21.eps  
FIG. 1.32  
38.eps  
FIG. 1.35  
68.eps  
B063  
11  
Removing the safety valve  
Removing the main circuit flow switch  
1. Loosen nut Z(FIG. 1.36);  
2. Unscrew and remove the valve (FIG. 1.37).  
1. Remove the cable of the main circuit flow switch B1”  
(FIG. 1.40);  
2. Remove the screws C1(FIG. 1.41);  
3. Remove the main circuit flow switch.  
Z
B1  
FIG. 1.36  
40.eps  
FIG. 1.40  
53.eps  
C1  
C1  
37.eps  
FIG. 1.37  
Removing the automatic air vent  
1. Unscrew valve top A1(FIG. 1.38);  
2. Remove valve (Fig 1.39).  
FIG. 1.41  
54.eps  
A1  
Fig. 1.38  
39.eps  
Fig. 1.39  
41.eps  
B063  
12  
Removing the pump  
1. Remove the U-clip D1(FIG. 1.41);  
2. Remove the retaining clip E1(FIG. 1.42);  
3. Remove the U-clip F1(FIG. 1.43);  
4. Release the nut G1(FIG. 1.44);  
5. Remove the pipe H1(FIG. 1.45);  
6. Remove the screws I1(FIG. 1.46);  
7. Remove the pump (FIG. 1.47).  
G1  
42.eps  
32.eps  
35.eps  
FIG. 1.44  
D1  
H1  
31.eps  
FIG. 1.41  
FIG. 1.42  
FIG. 1.43  
FIG. 1.45  
FIG. 1.46  
FIG. 1.47  
E1  
I1  
I1  
33.eps  
F1  
34.eps  
25.eps  
B063  
13  
Removing the pressure gauge  
Removing the expansion vessel  
1. Remove the U-clip J1and remove the pressure gauge  
coupling (FIG. 1.48);  
1. Loosen nuts K1and remove the gas pipe (FIG. 1.50);  
2. Loosen nut L1(FIG. 1.51);  
2. Push the pressure gauge through the control panel from  
the rear (FIG. 1.49).  
3. Remove back nut M1(FIG. 1.52);  
4. Remove the expansion vessel (FIG. 1.53).  
K1  
K1  
J1  
FIG. 1.50  
77.eps  
34.eps  
FIG. 1.48  
L1  
FIG. 1.51  
57.eps  
FIG. 1.49  
27.eps  
M1  
FIG. 1.52  
58.eps  
FIG. 1.53  
59.eps  
B063  
14  
Removing the overheat thermostat  
Removing the D.H.W. temperature sensor (N.T.C.)  
1. Disconnect the overheat thermostat electrical  
connections N1(FIG. 1.54);  
1. Pull off the electrical connector Q1and unscrew the  
sensor probe using a suitable spanner (FIG. 1.57).  
2. Then remove the thermostat from its mounting by  
releasing the securing clip (FIG. 1.55).  
Q1  
N1  
FIG. 1.57  
60.eps  
Removing the divertor valve actuator  
FIG. 1.54  
80.eps  
1. Unplug the electrical connector R1(FIG. 1.58);  
2. Release the retaining clip S1and remove the divertor  
valve actuator.  
R1  
S1  
83.eps  
FIG. 1.55  
74.eps  
FIG. 1.58  
Removing the heating temperature sensor (N.T.C.)  
Removing the D.H.W. flow switch  
1. Pull off the electrical connector P1and unscrew the  
1. Unplug the electrical connector T1(FIG. 1.59);  
2. Release the retaining clip V1and remove the D.H.W.  
flow switch.  
sensor probe using a suitable spanner (FIG. 1.56).  
V1  
P1  
T1  
FIG. 1.56  
FIG. 1.59  
30.eps  
87.eps  
B063  
15  
Removing the time clock  
1.6  
ACCESS TO THE CONTROL SYSTEM  
1. Unplug electrical connection W1from the clock (FIG.  
1.62);  
Checking the fuses  
2. Remove the screws W2(see fig. 1.63);  
3. Remove the clock from the panel (see fig. 1.64).  
1. Remove the inspection cover on the reverse of the  
control panel (FIG. 1.60);  
2. Remove the fuses (FIG. 1.61).  
W1  
69.eps  
1189.jpg  
1190.tif  
FIG. 1.62  
FIG. 1.63  
FIG. 1.64  
FIG. 1.60  
72.eps  
W2  
FIG. 1.61  
61.eps  
B063  
16  
Removing the P.C.B.  
1. Isolate electricity;  
2. Remove the inspection cover from the reverse of the  
control panel;  
3. Unplug all electrical connections from the P.C.B. (FIG.  
1.65);  
Y1  
4. Remove the screws X1(FIG. 1.66);  
5. Separate the facia panel from the rear of the control  
panel (FIG. 1.67);  
7. Remove the screws Y1and remove the P.C.B. (FIG.  
1.68).  
Y1  
82.eps  
FIG. 1.68  
FIG. 1.65  
64.eps  
X1  
X1  
X1  
X1  
X1  
X1  
FIG. 1.66  
1187.eps  
65.eps  
FIG. 1.67  
B063  
17  
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)  
PRELIMARY CHECKS  
MAKE SURE THAT:  
1 - There is sufficient water in  
the system  
2 - The gas is turned on  
3 - The electrical supply is  
turned on  
TURN ON THE ON/OFF  
SWITCH  
IS  
THE POWER  
NO  
L.E.D.  
ON?  
1 - Check the fuses  
YES  
2 - Check the power supply  
cable, plug and outlet  
3 - Check/replace the power  
supply to the P.C.B.  
POSTION  
OF THE  
SELECTOR  
SUEMSTMAETRE  
WINTER  
ECONOMY/  
COMFORT  
SELECTOR  
Comfort  
ECONOMY/  
COMFORT  
SELECTOR  
Comfort  
TEMP.  
C.H. < 34°C  
TEMP.  
C.H. < 34°C  
YES  
NO  
Economy  
NO  
Economy  
YES  
NO  
NO  
D.H.W. IS  
BEING DRAWN?  
YES  
D.H.W. IS  
BEING DRAWN?  
YES  
NO  
1 - Check/reset system  
pressure  
NO  
2 - Check/restore gas  
supply  
3 - Check/replace short-  
circuited heating probe  
4 - Check/replace siezed  
pump  
MUST  
TIME CLOCK  
AND/OR ROOM  
THERMOSTAT  
BE ACTIVATED?  
YES  
1 - Check/reset the  
system pressure  
2 - Check/restore  
gas supply  
3 - Check/replace short-  
circuited heating probe  
4 - Check/replace  
siezed pump  
FOR BOILERS  
WITH ELECTRONIC  
ANTI-FROST DEVICE:  
PROTECTION IS ACTIVATED  
IF HEATING TEMP  
IS < 5  
NO  
NO  
YES  
°
C
FOR BOILERS  
WITH ELECTRONIC  
ANTI-FROST DEVICE:  
NO  
YES  
PROTECTION IS ACTIVATED  
IF HEATING TEMP  
IS < 5  
°
C
A
FC004Aa  
B063  
18  
A
IS THE PUMP  
RUNNING?  
NO  
YES  
POWER TO  
THE PUMP?  
NO  
YES  
DOES THE  
"NO WATER" L.E.D.  
ILLUMINATE  
(WITHIN 40 SECS)?  
YES  
1 - Check pump cable  
2 - Check/replace P.C.B.  
3 - Check main flow main  
switch operation when  
drawing D.H.W.  
1 - Check if there is air in the  
system  
2 - Check main circuit flow switch  
operation  
3 - Check pressure on the water  
gauge and fill system to return  
to 1 bar  
1 - Check that the pump  
is not stuck  
2 - Release/replace pump  
NO  
1 - Turn the boiler off then on  
(protection reset)  
B
FC004Ab  
B063  
19  
B
IS THE FAN  
RUNNING?  
NO  
YES  
BOILER  
SHUTDOWN?  
1 - Reset the boiler  
YES  
YES  
NO  
C
1 - Check/replace main  
circuit flow switch  
2 - Check/replace  
PUMP PROTECTION  
ACTIVATED?  
connection cable  
3 - Check/replace P.C.B.  
NO  
1 - Check/replace air  
pressure switch  
2 - Check if reset button  
is jammed  
3 - Check/replace flame  
detection electrodes  
INTERNAL  
P.C.B. PROTECTION  
ACTIVATED?  
YES  
NO  
NO  
1 - Check/replace  
connection cable  
2 - Check/replace P.C.B.  
3 - Check/replace air  
pressure switch  
POWER  
TO FAN?  
YES  
1 - Replace fan  
FC004Ac  
B063  
20  
C
IS THE  
AIR PRESSURE SWITCH  
ACTIVATED?  
NO  
CHECK  
P ON TEST  
PRESSURE  
INTAKE  
1 - Check A.P. switch cable  
2 - Check/replace A.P. switch  
3 - Check/replace P.C.B.  
YES  
P 1.2 mbar  
1 - Check exhaust discharge  
2 - Check venturi & pipes  
3 - Check fan efficiency  
P 1.2 mbar  
1 - Check/replace ignition  
electrode  
2 - Check ignition cable  
3 - Check spark generator  
4 - Check ignition electrode  
cable  
IS FLUE  
DISCHARGE  
NORMAL?  
NO  
5 - Check/replace P.C.B.  
YES  
1 - Check power supply of  
gas valve  
2 - Check/replace P.C.B.  
3 - Check efficiency of  
gas valve  
IS THE BURNER  
ALIGHT?  
NO  
4 - Replace gas valve  
YES  
1 - Check if flame strikes  
detection electrode  
2 - Check soft-light gas  
pressure  
3 - Check/replace detection  
electrode  
HAS THE  
BOILER SAFETY  
SHUTDOWN BEEN  
ACTIVATED?  
YES  
4 - Check/replace P.C.B.  
NO  
HAS THE  
BOILER SAFETY  
SHUTDOWN BEEN  
ACTIVATED?  
D
NO  
YES  
Shutdown L.E.D. off  
fan restarts  
FC004Ad  
B063  
21  
D
FAULTS  
POSSIBILE CAUSES  
IS  
THERE STILL  
A PROBLEM?  
Drawing D.H.W:  
1
2
- air in secondary heat exchanger  
- faulty main circuit flow switch  
- faulty D.H.W. flow switch  
YES  
When you turn on a tap  
burner switches off  
Drawing D.H.W:  
- faulty 3-way valve  
NO  
radiators heat up in summer mode  
3 Drawing D.H.W:  
insufficient hot water  
temperature  
- check C.H./D.H.W. temperature probes  
- check gas pressures  
- check water flow rate  
NORMAL  
OPERATION  
- check secondary heat exchanger  
- primary heat exchanger faulty or  
4
5
Drawing D.H.W:  
noisy operation  
lime-scale deposits  
- low heating system water pressure  
- check gas pressures  
-
check C.H./D.H.W. temperature probes  
Decrease/increase  
heating circuit pressure  
- check for leaks on the heating circuit  
- faulty filling-loop  
- faulty secondary heat exchanger  
- expansion vessel faulty  
Repeated shutdowns  
6
7
- faulty detection electrodes  
- check gas settings  
- check flame detection electric circuit  
Repeated intervention of safety thermostat  
- C.H./D.H.W. temperature probes open circuit  
- overheat thermostat not calibrated correctly  
- air in primary water circuit  
8 When cold water tap turned off, the boiler  
ignites  
- drop in pressure in the water mains, with  
consequent water hammer  
9
Insufficient radiator temperature  
- check C.H. temperature probe  
- check by-pass  
- check gas pressures  
FC004Ae  
B063  
22  
LEGEND:  
3.  
ELECTRICAL  
DIAGRAMS  
A
B
=
=
Time Clock Connector  
Central Heating Selection (Winter) and  
Temperature Adjustment  
Connector for Total Check System  
Domestic Hot Water Temperature Adjustment  
Soft-light Adjustment  
Maximum Heating Adjustment  
On/Off Switch  
On/Off L.E.D.  
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
V
U
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
Fume Sensor L.E.D.  
Ignition Failure (Lockout) L.E.D.  
Low System Water Level/Lack of Circulation L.E.D.  
Reset Button  
Economy/Comfort Selector  
Overheat L.E.D.  
Temperature L.E.D.s  
Transformer  
Circulation Pump Relay  
Fan Relay  
Gas Valve Relay  
Motorised Diverter Valve Relay  
Spark Generator  
Anti-cycling Device Adjustment for Heating  
A01  
A02  
A03  
A04  
A05  
A06  
A07  
A08  
A09  
A10  
A11  
A12  
A13  
A14  
=
=
=
=
=
=
=
=
=
=
=
=
=
=
Circulation Pump  
Fan  
Spark Generator/Gas Valve Supply  
Motorised Diverter Valve  
Flame Detection Circuit  
Detection Electrode  
Main Circuit Temperature Probe  
Domestic Hot Water Temperature Probe  
Domestic Hot Water Flow Switch  
Main Circuit Flow Switch  
Modulator  
Air Pressure Switch  
Safety Thermostat  
External (Room) Thermostat  
Colours:  
Gry  
Wh  
Pnk  
Brn  
=
=
=
=
=
=
Grey  
White  
Pink  
Brown  
Blue  
Bl  
Blk  
Black  
Rd/Blk = Red/Black  
B063  
23  
microGENUS 23/27 MFFI  
J
K
SE017A  
N
O
R
T
Q
S
J
U
K
L
M
SF014A  
B063  
24  
4.  
SHORT SPARE  
PARTS LIST  
microGENUS 23/27 MFFI  
9
62 61 60  
59 58 57 56 9 55 54  
53  
304  
52  
51  
1
2
50  
63  
3
4
56  
9
56  
9
64  
5
56  
301  
302  
303  
107  
106  
65  
108  
5
66  
6
49  
48  
7
105  
8
9
104  
67  
103  
102  
9
68  
47  
46  
10  
10  
69  
97  
101  
98  
70  
71  
45  
99  
100  
71  
11  
12  
13  
72  
73  
14  
12  
13  
44  
43  
74  
96  
75  
76  
77  
14  
15  
16  
42  
41  
95  
42  
94  
85  
86  
80  
84  
77  
83  
82  
79  
93  
92  
34  
40  
87  
14  
81  
78  
88  
91  
90  
25  
17  
89  
14 18 19 20 21 18 22  
code 998613  
23 24  
25  
26 27 28  
352  
29 30 31  
32 33  
34  
35  
36 37 38  
39  
codes 998836  
code 998940  
999091  
351  
331  
311  
334  
353  
354  
333  
332  
code 998099  
code 997089  
371  
372  
373  
MODELS  
CHARACTERISTICS  
SERIAL NO:  
VALIDITY  
REF.  
MICROGENUS 23 MFFI  
MICROGENUS 23 MFFI  
METHANE  
LPG  
2320005600001  
2320005600001  
A
B
374  
MICROGENUS 27 MFFI  
MICROGENUS 27 MFFI  
METHANE  
LPG  
2320005600001  
2320005600001  
C
D
321  
375  
B063  
25  
microGENUS 23/27 MFFI  
Key  
no.  
G.C. part  
no.  
ARISTON  
Part No.  
Description  
2
5
998616  
573521  
998077  
573520  
997147  
997077  
569236  
998613  
571547  
998099  
998940  
998424  
574279  
998645  
997089  
998836  
999091  
999599  
998947  
999245  
573989  
571651  
999397  
998894  
997206  
998620  
998893  
998618  
998669  
998887  
998939  
571646  
573295  
573825  
573172  
998623  
998622  
998624  
998941  
997029  
998490  
998718  
998975  
998974  
998644  
998643  
998738  
998961  
999207  
571547  
571772  
571771  
571770  
998172  
998716  
998717  
379816  
Expansion vessel  
Gasket 3/8"  
O-ring  
Gasket 3/4"  
Motor (3- Way valve)  
Fixing clip (motor)  
Temperature probe (C.H.W.)  
Flow group  
Diaphragm (main flow switch)  
Main circuit flow switch  
Return group  
O-ring  
Gasket  
Spark generator  
Gas valve (SIT 845 SIGMA)  
Pump  
E61 468  
1
164 282  
E61 475  
164 225  
E25 427  
E61 429  
164 338  
E61 478  
E24 077  
E61 479  
E61 482  
E61 483  
E25 529  
E61 848  
E61 485  
E61 490  
E61 881  
12  
14  
16  
17  
18  
19  
20  
21  
24  
25  
26  
27  
28  
33 AB  
33 CD  
38  
41  
43  
52AB  
52CD  
66AB  
66CD  
72  
74AB  
74CD  
75A  
75B  
75C  
75D  
76AB  
76CD  
77  
79  
98  
99  
100  
311  
321  
331  
332  
333  
334  
351  
352  
353  
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Pump  
Time clock  
E61 519  
E61 520  
E61 530  
E03 818  
P.C.B. (CMP1-FFI)  
Pressure gauge  
Air pressure switch  
Air pressure switch  
Fan  
1
1
E61 967  
E25 425  
Fan  
Thermostat (overheat)  
Main exchanger  
Main exchanger  
1
E61 546  
E61 547  
E61 549  
E61 972  
E61 974  
E26 767  
E26 657  
E26 658  
E26 378  
E61 565  
E61 567  
E61 569  
Burner 12 ramp (natural gas)  
Burner 12 ramp (LPG)  
Burner 14 ramp (natural gas)  
Burner 14 ramp (LPG)  
Secondary exchanger (p-type 23kW)  
Secondary exchanger (p-type 27kW)  
O-ring (secondary exchanger)  
Safety valve (1/2" 3 bar)  
Electrode (Ignition R.H.)  
Electrode (Ignition L.H.)  
Detection electrode  
D.H.W. actuator kit  
Operator coils (SIT SIGMA)  
Central heating by-pass kit  
Heating spring kit  
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
E25 582  
E61 647  
E61 648  
E61 649  
E61 650  
E61 652  
E61 654  
E61 656  
E61 660  
E62 030  
E24 077  
E24 077  
E24 076  
E24 075  
E61 663  
E61 665  
E61 667  
3-way spring kit  
Actuator bush  
Gasket (auto air vent)  
Auto air vent  
Gasket (pump head)  
Pump head (Gold 15/5)  
Pump head  
Diaphragm (main flow switch)  
Magnet (main flow switch)  
Spring (main flow switch)  
Main flow switch top cap  
Main flow switch reed system  
Burner jet 1.25 full kit (Natural gas)  
Burner jet 0.72 full kit (LPG)  
354 AB  
354 CD  
371  
372  
373  
374  
375  
381  
382  
B063  
26  
Manufacturer:  
Merloni TermoSanitari SpA - Italy  
Commercial subsidiary: MTS (GB) LIMITED  
MTS Building  
Hughenden Avenue  
High Wycombe  
Bucks HP13 5FT  
Telephone: (01494) 755600  
Fax: (01494) 459775  
Technical Service Hot Line: (01494) 539579  
SPARE PARTS EXPLODED VIEW  
GAS WALL BOILERS  
Models  
MICROGENUS 27 MFFI  
Edition 2 of 1 February 2000  
9
61 60 59  
58 57 56 55 9 54 53  
52  
304  
51  
50  
1
2
62  
3
4
55  
9
55  
9
5
55  
301  
302  
303  
104  
63  
64  
105  
103  
5
6
7
49  
48  
65  
102  
101  
8
9
66  
100  
9
47  
46  
10  
10  
99  
67  
94  
98  
68  
69  
45  
95  
96  
97  
69  
11  
12  
13  
70  
71  
14  
12  
13  
44  
43  
72  
93  
73  
74  
75  
14  
15  
16  
42  
41  
92  
42  
83  
84  
78  
82  
75  
81  
80  
77  
34  
40  
91  
90  
85  
14  
79  
76  
86  
89  
88  
25  
17  
87  
14 18 19 20 21 18 22  
23 24  
25  
26 27 28  
29 30 31  
cod. 999091  
32 33  
34  
35  
36 37 38  
39  
cod. 998613  
cod. 998940  
352  
351  
331  
311  
334  
333  
353  
332  
354  
cod. 997089  
cod. 998099  
371  
372  
373  
MODELS  
CHARACTERISTICS  
METHANE  
SERIAL NO:  
VALIDITY  
REF.  
A
374  
MICROGENUS 27  
MFFI  
0002601386  
321  
375  
MICROGENUS 27  
MFFI  
LPG  
0002601388  
B
PART CODE DESCRIPTION  
REF.  
NOTE  
1
------  
Frame  
11  
2
3
998616 Expansion vessel  
998776 Bush  
4
5
998581 3/8" lock nut  
573521 Gasket 3/8"  
6
7
999102 Pipe (expansion vessel)  
998580 Cable holder  
8
------  
Hydraulic group support  
11  
9
570717 Spring (fastening)  
998569 Pivot  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
26  
27  
28  
29  
30  
31  
32  
33  
34  
35  
36  
37  
38  
39  
40  
41  
42  
43  
44  
45  
46  
47  
48  
49  
50  
51  
52  
53  
54  
55  
56  
57  
58  
59  
60  
61  
62  
63  
64  
65  
998589 By-pass pipe  
998077 O-ring gasket  
998064 Spring (by-pass pipe)  
573520 Gasket 3/4"  
999103 Pipe (flow)  
997147 Motor (3-Way valve)  
997077 Fixing clip (motor)  
569236 Temperature probe (C.H.W.)  
998613 Flow group  
571547 Diaphragm (main flow switch)  
998099 Main circuit flow switch  
998632 Cable (temperature probes)  
999075 D.H.W. flow switch  
998940 Return group  
998424 O-ring  
574279 Gasket  
998645 Spark generator  
997089 Gas valve (SIT 845 SIGMA)  
998606 Pump bracket  
998568 Pump plug  
997182 Gasket  
999100 Lock washer  
999091 Pump  
998570 L.E.D.  
998575 Spindle (temperature knob)  
998603 Control knob  
998572 Spindle (on/off knob)  
997207 Time clock  
999059 Front cover  
998824 Control panel  
998947 Printed circuit board (CMP1-FFI)  
569711 Nylon bush (10mm)  
998625 Pressure gauge  
998952 Control panel  
998953 Cable holder cover  
571548 Clip(Main Flow Switch)  
998861 Cable (power supply)  
999153 High voltage wiring  
998863 Low voltage wiring  
573327 Y piece (air pressure)  
571651 Air pressure switch  
997203 Support plate (Air pressure switch)  
573329 Pressure intake cover  
571575 Silicone pipe (positive signal)  
998516 Gasket (adhesive 10x6)  
------  
Sealed chamber  
11  
998565 Cover (flue test point)  
998636 Gasket (flue test point)  
998602 Flue (exhaust manifold/header)  
998637 Flange gasket  
998595 Plug (air intake)  
998648 Wiring loom (fan/air pressure switch)  
998566 Fixing clamp (fan)  
573446 Fan seal (silicone)  
998943 O-ring (2.65 x 101.27)  
PART CODE DESCRIPTION  
REF.  
NOTE  
66  
998894 Fan  
67  
68  
69  
70  
71  
72  
998896 Insulation panel (Rear)  
998964 Panel (combustion chamber - L.H. side)  
998639 Insulation panel (Side)  
997206 Thermostat (overheat)  
998583 Fixing spring (overheat thermostat)  
998893 Main exchanger  
73  
73  
74  
75  
76  
77  
78  
998887 Burner 14 ramp (NG)  
998939 Burner 14 ramp (LPG)  
573295 Secondary exchanger (p-type 27kW)  
573825 O-Ring (secondary exchanger)  
998629 Cable (3-way valve motor)  
573172 Safety valve (1/2" 3 bar)  
573528 Gasket 1/2"  
A
B
79  
80  
81  
998019 Pipe (safety valve outlet)  
573576 Compensation tube  
573325 Rivet  
82  
569443 Silicone seal  
83  
572138 Burner jet washer  
84  
84  
85  
998433 Burner jet (NG 1.30)  
998434 Burner jet (LPG 0.77)  
998729 Pipe (gas valve)  
A
B
86  
998732 Pipe (C.H. return)  
87  
997153 U-clip  
88  
998604 Reset button  
89  
90  
91  
998571 Reset button (insert)  
999148 Selector button (comfort)  
998579 Spindle (comfort)  
92  
93  
998862 Cable (detection electrode)  
569720 Blind grommet  
94  
998517 Gasket  
95  
96  
97  
98  
998623 Electrode (Ignition R.H.)  
998622 Electrode (Ignition L.H.)  
998624 Detection electrode  
998147 Ignition electrode cable rubber  
998963 Panel (combustion chamber - R.H.side)  
998924 Panel (combustion chamber front)  
998925 Flue hood  
998895 Insulation panel (Front)  
998076 View window glass gasket  
998075 View window glass  
998610 Panel (front - sealed chamber)  
998477 Case panel (L.H. side)  
998596 Insert (case)  
99  
100  
101  
102  
103  
104  
105  
301  
302  
303  
304  
311  
321  
331  
332  
333  
334  
351  
352  
353  
354  
371  
372  
373  
998476 Case panel (R.H. side)  
998607 Panel (front case)  
998941 D.H.W. actuator kit  
997029 Operator coils (Sit Sigma)  
998490 Central heating by-pass kit  
998718 3-Way spring kit (C.H.)  
998975 3-Way spring kit (D.H.W.)  
998974 Heating actuator bush  
998644 O-ring (A.A.V.)  
998643 Auto Air Vent  
998738 Gasket (pump head)  
999207 Pump head  
571547 Diaphragm (main flow switch)  
571772 Magnet (main flow switch)  
571771 Spring (main flow switch)  
PART CODE DESCRIPTION  
REF.  
NOTE  
374  
375  
381  
382  
571770 Main flow switch top cap  
998172 Main flow switch reed system  
998716 Burner jet full kit (NG)  
998717 Burner jet full kit (LPG)  
12  
12  
NOTE DESCRIPTION  
11 Not supplied as a spare part  
12 Not illustrated  

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