Biasi M96A.24SM/B User manual

Wall hung, fan flue, room sealed, high efficiency gas boiler
User manual and
Installation instructions
GARDA HE MK2
Models
M96A.24SM/B Combi boiler
M96A.28SM/B Combi boiler

Congratulations on your choice.
GARDA HE MK2 are condensing high efficiency sealed chamber fan flue gas boilers.
They are fully electronically controlled and have electronic ignition.
Thematerialstheyaremadeofandthecontrolsystemstheyareequippedwithgiveyousafety,
a high level of comfort and energy savings to allow you to get the greatest benefit out of
independent heating.
GARDA HE MK2 allow a higher efficiency by reducing the flue gas temperature such that the
water vapour formed during the combustion is condensed out.
This allows a gain of useful heat that otherwise would be lost.
Remember that...
nThe manual
--- must be read thoroughly, so that you will
be able to use the boiler in a safe and sen-
sible way;
--- must be carefully kept. It may be necess-
ary for reference in the future.
nFirst lighting up must be carried out by
competent and responsible engineer.
nThe manufacturer
--- disclaim all liability for any translations of
the present manual from which incorrect in-
terpretation may occur
--- cannot be held responsible for non --- ob-
servance of instructions contained in this
manual or for the consequences of any pro-
cedure not specifically described.
Using the boiler...
nBefore lighting the boiler you are ad-
vised to have a professionally qualified per-
son check that the installation of the gas
supply
--- is gas---tight;
--- is of the correct gauge for the flow to the
boiler;
--- is fitted with all the safety and control de-
vices required by the current Regulations.
nEnsure that
--- the installer has connected the pressure
relief valve outlet to a drain pipe. The manu-
facturers are not responsible for damage
caused by opening of the pressure relief
valve and consequent escape of water, if not
connected correctly to the drain.
--- the installer has connected the conden-
sate outlet to a suitable drain pipe.
nOn detecting the smell of gas
--- don’t operate any electrical switches, the
telephone or any device that may produce
sparks;
--- open the windows and doors at once to
create a draught of air which will purge the
area;
--- shut off the gas cocks;
--- get the assistance of a qualified person.
nDo not touch the appliance with parts of
thebodythatarewetordampand/orbare
feet.
nDo not block or modify the condensate
outlet and pipework
nIn case of structural work or mainten-
ance near the exhaust duct and/or fume ex-
haust devices or their attachments, turn off
the appliance. On completion of the work,
have a professionally qualified person check
their efficiency.
nRepairs (under guarantee) must be car-
ried out only by an approved engineer, using
genuine spare parts. Thus do no more than
switching off the boiler yourself (see the in-
structions).
nYour boiler allows heating up of water to
a temperature less than boiling point;
--- must be connected to a central heating
system and/or a hot water supply system,
compatible with its performance and output;

--- can be used only for those purposes for
which it has been specially designed;
--- must not be touched by children or by
those unfamiliar with its operation;
--- must not be exposed to weather condi-
tions.
nDuring the operation it is quite normal
that the boiler produces a white plume of
condensation vapour from the flue terminal.
This is due to the high efficiency of the ap-
pliance and may be particularly evident with
low outdoor temperatures.
Safe handling of
appliance
When handling or lifting always use safe tech-
niques
--- keep your back straight, bend your knees, don’t
twist
--- move your feet, avoid bending forwards and
sideways and keep the load as close to your body
as possible.
Wherepossibletransporttheboilerusingasack
truck or other suitable trolley.
Always grip the boiler firmly, and before lifting feel
where the weight is concentrated to establish the
centre of gravity, repositioning yourself as necess-
ary.
Safe handling of
substances
These products are manufactured in accordance
with ISO 9000 and do not, and will not, contain any
hazardous materials or substances such as as-
bestos, mercury or C.F.C.’s.
The appliance packaging does not contain any
substances, which may be considered a hazard to
health.
Combustion chamber panels
Material: mineral fibres
Known hazards --- Some people can suffer red-
dening and itching of the skin. Fibre entry into the
eye will cause foreign body irritation, which can
cause severe irritation to people wearing contact
lenses. Irritation to respiratory tract.
Precautions --- Dust goggles will protect eyes.
People with a history of skin complaints may be
particularly susceptible to irritation. High dust le-
vels are only likely to arise following harsh ab-
rasion. In general, normal handling and use will
not present high risk, follow good hygiene prac-
tices, wash hands before, touching eyes, consum-
ing food, drinking or using the toilet.
Firstaid--- Medicalattentionmustbesoughtfol-
lowing eye contact or prolonged reddening of the
skin.
Thermostat / Temperature gauge
Description --- Sealed phial and capillary contain-
ing liquid.
Known hazards --- irritating to skin, eyes and
throat. Vapour is harmful. Inflammable --- do not
extinguish with water.
Precautions --- Do not incinerate. Avoid contact
with broken/leaking phials. Do not purposely
puncture.
Firstaidmedicalattentionmustbesoughtfollow-
ing eyes/skin contact, wash with clean water.
Appliance category II2H3+ Gas G20 20 mbar, G30 29 mbar, G31 37 mbar
Country of destination: United Kingdom (GB) Ireland (IE)
This appliance conforms with the following EEC directive:
DGas appliance Directive 90/396/CEE
DBoiler Efficiency Directive 92/42/CEE
DElectromagnetic Compatibility Directive 89/336/CEE
DLow voltage Directive 73/23/CEE
The manufacturer, in the continuous process to improve his products, reserves the right to modify the
data expressed in the present documentation at any time and without prior notice.
The present documentation is an informative support and it cannot be considered as a contract to-
wards third parties.

Boiler installation and commissioning tips
nThe installation must be carried out by
a qualified person who will be responsible for
observing the current Regulations.
Installing the boiler...
nDonotforgettoremovethetransitcaps
and plugs from the boiler connections these
are fitted to every boiler.
nKeep the boiler clear of dust during in-
stallation and in particular do not allow any
dust or debris to enter the top of the boiler
where the flue connection is made. It is rec-
ommended that you put a dust sheet over the
top of the boiler until you are ready to make
the flue connection.
nBecause every boiler is fired and tested
live at the factory, a small amount of water re-
mains within the boiler. It is possible for this
water to initially cause the pump to seize. It is
therefore recommended that the pump rotor
be manually turned to free its rotation before
turning the boiler on.
nRemember to release the auto air purge
before filling the boiler. See the instructions to
identify the location of this device.
nDo not remove the cap of the pressure
test points of the air switch (top left side of the
boiler).
nYou are strongly advised to flush out the
system both cold and hot in order to remove
system and installation debris.
nIt is also sensible to initially fire and com-
mission the boiler before connecting any ex-
ternal controls such as a room thermostat. By
this method if you have a subsequent prob-
lem following the addition of an external con-
trol you can eliminate the boiler from your
fault analysis.
nDonotforgettorangeratetheboilerto
suit the system requirements. This pro-
cedure is covered in the commissioning sec-
tion of the installation manual.
nIf the boiler is fitted with a digital pro-
grammer, when setting the times for auto-
matic operation, remember that for every
“ON” time there must be an “OFF” time to fol-
low and that on every occasion you enter a
time you must also indicate which days that
you want the boiler to follow the timed set-
tings.
nSome products incorporate an anti cycl-
ing time delay. It is normal when first switch-
ing the boiler on for the boiler to operate on
heating for a few seconds then switch off.
After 3 --- 4 minutes has elapsed the boiler will
then re ignite and operate perfectly normally.
The ignition delay cycle does not prevent
normal operation of the boiler to provide
d.h.w.
nIf you are in any doubts as to the installa-
tion or operation of the boiler please read the
instruction manuals thoroughly and then if
necessary contact Biasi UK for advice and
assistance.
Please remember that if you are in any doubt about the installation of this product you can contact our
Technical Helpline on tel. [phone]

TABLE OF CONTENTS
1
1 Appliance description 2..........
1.1 Overview 2......................
1.2 Control panel 2..................
1.3 Isolation valves 2.................
1.4 Technical data 2.................
1.5 Operation lights 3................
2 Instructions for use 4............
2.1 Warnings 4......................
2.2 Refilling procedure 4..............
2.3 Ignition 5........................
2.4 C.h. circuit temperature 5..........
2.5 D.h.w. temperature 6..............
2.6 Extinguishing 6..................
2.7 Built in time switch A 7............
2.8 Built in time switch B 9............
3Usefuladvice 11.................
3.1 Central heating 11.................
3.2 Frost protection 11................
3.3 Condensate drain 11..............
3.4 Periodic maintenance 11...........
3.5 External cleaning 11...............
3.6 Operational faults 11...............
4 Technical information 13..........
4.1 Overview 13......................
4.2 Main diagram 14..................
4.3 Hydraulic specifications 15.........
4.4 Expansion vessel 15...............
4.5 Technical data mod. M96A.24SM/... 16
4.6 Technical data mod. M96A.28SM/... 18
5 General requirements 20..........
5.1 Related documents 20.............
5.2 Location of appliance 20...........
5.3 Flue system 20....................
5.4 Gas supply 21....................
5.5 Air supply 21.....................
5.6 Ventilation 21.....................
5.7 Condensate drain 21..............
5.8 Water circulation (c.h.) 22...........
5.9 Domestic water 23.................
5.10 Water treatment 23................
5.11 Electrical supply 23................
6 Installation 25....................
6.1 Warnings 25......................
6.2 Precautions for installation 25.......
6.3 Installing the bracket 25............
6.4 Overall dimensions 26.............
6.5 Joints 26.........................
6.6 Mounting the boiler 26.............
6.7 Fitting the flue system 27...........
6.8 Choice of flue 27..................
6.9 Electrical connections 30...........
6.10 External frost protection 31.........
7 Commissioning 32...............
7.1 Electrical installation 32............
7.2 Gas supply installation 32..........
7.3 Filling the d.h.w. system 32.........
7.4 Initial filling of the system 32........
7.5 Condensatepipeandtraps 33......
7.6 Lighting the boiler 33..............
7.7 Checking the gas pressure
at the burner 33...................
7.8 Checking the burner ignition 34.....
7.9 Checking the ignition device 35.....
7.10 Checking the flue system 35........
7.11 Checking the condensate drain pipe 35
7.12 Instructing the user 35.............
8 Gas conversion 36...............
8.1 Warnings 36......................
8.2 Procedures 36....................
9 Maintenance 38..................
9.1 Warnings 38......................
9.2 Dismantling the external panels 38...
9.3 Emptying the d.h.w. system 38......
9.4 Emptying the c.h. system 38........
9.5 Combustion analysis check 39......
9.6 Cleaning the primary heat exchanger 39
9.7 Checking the pressurisation
in the expansion vessel 39..........
9.8 Cleaning the burner 39.............
9.9 Checking the flue 39...............
9.10 Drain pipe inspection 39............
9.11 Visual inspection of appliance 39....
9.12 Gas pressures and tightness 39.....
Abbreviations used in the manual
C.h. = Central heating
D.h.w. = Domestic hot water
D.c.w. = Domestic cold water
USE
INSTALLATIONMAINTENANCE

1APPLIANCE DESCRIPTION
2
1.1 Overview
2
1
3
Fig. 1.1
1 Case front panel
2 Control panel
3 Control panel cover
1.2 Control panel
4 C.h. circuit temperature and pressure gauge
5 Time switch (c.h. control)
6 Lock --- out signal lamp
7 Lockout reset button
8 Function selector and c.h. temp. control knob
9 D.h.w. temperature control knob
10 Appliance operation lights
1.3 Isolation valves
14 1216 1315 11
Fig. 1.2 (bottom view of the boiler)
11 Condensate drain pipe
12 C.h. return valve
13 D.c.w. inlet valve
14 Gas inlet valve
15 D.h.w. outlet pipe
16 C.h. flow valve
1.4 Technical data
For detailed technical data see section 4.5 or 4.6
of this manual.
10 89 7 6 45
Fig. 1.3
USE

Appliance description
3
1.5 Operation lights
Three lights (10 in Fig. 1.3) give detailed indication
regarding the operation of the boiler.
The following table gives the relationship between
each of the possible light combinations and their
meaning.
A short pulse every 4
seconds:
stand --- by condition
Function selector in
position.
Anti --- freeze system active
1 second pulse every 2
seconds: normally
operating boiler. Function
selector in or
position
C.h. operation
D.h.w. operation
Frost protect operation
D.h.w. operation
Excessive temperature on
primary circuit
If the lights combination observed is not included
in the above table a fault may be indicated.
Reference should be made to the following table.
In this case switch off the boiler, as described in
section 2.6 on page 6 and call a competent and re-
sponsible Service Engineer.
Faulty c.h. temperature
probe NTC
Faulty d.h.w temperature
probe NTC
Faulty flue temperature
probe NTC
Faulty primary circuit
(no water or low c.h.
pressure)
Faulty primary circuit
(absence of flow)
Faulty air pressure sensor
Lack of burner ignition (no
ignition signal from the full
seqence ignition device)
Safety thermostat lock out
Flue temperature probe
NTC lock out
Flame detection error
Other faults
Lack of power supply or
fauly electr. control p.c.b.
Meaning of symbols
L
amp OFF
L
amp ON
Flashing lamp, alone or simultaneously
with an other lamp.
Flashing lamp, alternate with another
lamp.
USE

2INSTRUCTIONS FOR USE
4
2.1 Warnings
Our Company supports the Benchmark in-
itiative. The Benchmark Log Book is lo-
cated at the back of this manual and should
be completed by the Installing/Commiss-
sioning Engineer and handed over to the
User for future reference by other visiting
Engineers. Also included is the Service In-
terval Record card that should be com-
pleted by the Service Engineer following
the annual service maintenance of the
boiler and system.
All CORGI Registered Installers carry a
CORGI ID card, and have a registration
number. Both should be recorded in your
Benchmark Log Book. You can check your
installer is registered by calling CORGI di-
rect on 01256 372300.
In order to guarantee safety and correct oper-
ation, it is essential that all the tests are carried
out by a competent and responsible service
engineer before lighting up the boiler.
The tests are described in the installation in-
structions in section 7 commissioning.
Ensure that the c.h. circuit is regularly filled
with water (even if the boiler is only used for
d.h.w. supply) checking that the pressure indi-
cated on the temperature and pressure gauge
4 is not lower than that shown in Fig. 2.2.
If the pressure reading on the pressure gauge
is below that shown in Fig. 2.2, then the system
will require topping up. A filling loop is normally
provided by the installer for this purpose.
If you are in any doubt regarding this pro-
cedure you are advised to contact your In-
staller or an Approved Engineer.
This appliance is provided with a built in anti---
freeze system that operates the boiler when
the temperature is below 5 ˚C
Therefore, when the boiler is not lit or used in
cold weather, with consequent risk of freezing
do not switch off the boiler at the fused spur
isolation switch or close the gas inlet cock.
When you do not expect to use the boiler for a
long period and the boiler is not to be used for
frost protection then follow the instructions
giveninsection2.6onpage6.
2.2 Refilling procedure
1 Isolate the boiler from the electrical supply at
the fused spur. Reconnect the filling loop as
demonstrated in Fig. 2.1.
Te m p o r a r y
connection
Control valve
Control valve
Double check valve
Supply pipe
(cold water inlet)
C.h. return pipe
Fig. 2.1
2 Open the valves of the filling loop and watch
the gauge until it reaches normal filling pres-
sure as shown in Fig. 2.2.
4
Normal filling
pressure
Fig. 2.2
3 Close the valves and remove the filling loop.
If you experience any difficulty with the oper-
ation of the boiler, switch off the boiler immedi-
ately at the fused spur isolation switch and
contactyourInstalleroranapprovedService
Engineer
Air introduced into the boiler during this filling pro-
cess will vent through the automatic air purger
fitted to the boiler. You may also find it necessary
to vent air from your radiator circuit using your
radiator key, however be aware that excessive
venting will cause the pressure in the system to
drop.
Always ensure that the pressure gauge is set at the
required pressure.
USE

Instructions for use
5
2.3 Ignition
1 Check that the valves located in the lower part
of the boiler are open (Fig. 2.3).
Open position
Fig. 2.3
2 Turn on the electricity supply to the boiler,
switching on the fused spur isolation switch.
The appliance operation light 10 (Fig. 2.4) will
flash every 4 seconds (stand---by condition).
3 If the boiler is to be used for c.h. and d.h.w,
position the function selector 8 as in Fig. 2.4.
The appliance operation light 10 will flash
every 2 seconds (operating boiler).
810
Fig. 2.4
4 If d.h.w. supply only is required, position the
function selector 8 as in Fig. 2.5.
The appliance operation light 10 will flash
every 2 seconds (operating boiler).
810
Fig. 2.5
2.4 C.h. circuit temperature
The output temperature of c.h. water is adjustable
from a minimum of about 40°C to a maximum of
about 85°C (Fig. 2.6), by turning the function se-
lector (8).
Adjustment of c.h. output on the boiler is auto-
matic. The greatest output pre--- set in the factory
can, however, be reduced in level according to
actual system requirements; this does not affect
the maximum output in d.h.w. operation.
Such adjustments must be carried out by a quali-
fied person; therefore we advise you to contact
yourinstallerorServiceAgent.
Adjustment of the boiler temperature alters the
gas flow at the burner according to the thermal de-
mand in the system. So it is usual to see theburner
lit at the minimum level for more or less long
periods.
Minimum
Maximum
Fig. 2.6
Adjustment
In order to achieve optimal settings for economy
and comfort, we recommend adjusting the oper-
ating temperature of the c.h. water according to
the outside temperature, positioning the knob as
follows:
Lower than
--- 5 ˚C
From 5 to 15 ˚CBetween
--- 5 a n d + 5 ˚C
Fig. 2.7
USE

Instructions for use
6
Your qualified installer will be able to recommend
the most suitable adjustment for your system.
The temperature and pressure gauge (4, Fig. 1.3
on page 2) will allow you to check that the set tem-
perature is obtained.
2.5 D.h.w. temperature
The temperature of the d.h.w. leaving the boiler
can be varied from a minimum of about 35°Ctoa
maximum of about 55°C (Fig. 2.8), by turning the
temperature control knob 9.
9
Minimum
Maximum
Fig. 2.8
Adjustment of the d.h.w. temperature is complete-
ly separate from that of the c.h. circuit.
The adjustment system integrated within the
boiler automatically controls the flow of gas to the
burner in order to keep the temperature of d.h.w.
delivered constant, between the limits of maxi-
mum and minimum output.
Where the demand is at a low level or with the tem-
perature set to the minimum, it is normal to see a
cycle of lighting and extinguishing of the burner
when running.
Adjustment
It is advisable to adjust the d.h.w. temperature to
a level commensurate with the demand, minimis-
ing the need to mix with cold water. In this way, the
automatic control facilities will be fully exploited.
Moreover, where the amount of limescale present
in the water may be particularly great, not exceed-
ing the position in Fig. 2.9 of the d.h.w. tempera-
ture control knob 9 corresponding to about 50°C
(Fig. 2.9), minimises annoying incidences of scale
deposits and clogging.
9
Fig. 2.9
In these cases, however, it is advisable to install a
small water treatment device or softener. With
such a device you should avoid periodic descal-
ing.
Consequently, the d.h.w. heat exchanger willkeep
its performance consistent for a longer period of
time with resulting gas savings.
If the demand for d.h.w. is so great as to prevent
reaching a high enough temperature, have the ap-
propriate output limiting valve installed by your in-
staller or an Authorised Service Engineer.
2.6 Extinguishing
To turn the boiler off set the function selector 8 to
the position shown in Fig. 2.10.
The appliance operation light 10 will flash every 4
seconds.
810
Fig. 2.10
When you do not expect to use the boiler for a long
period:
1 Switch off the electricity supply to the boiler, by
means of the fused spur isolation switch;
2 Shut off the gas supply cock 14 and the valves
for the water circuits fitted under the boiler
(Fig. 2.11).
USE

Instructions for use
7
3 Empty the water circuits, if necessary, as
showninsectionGeneral access and emptying
hydraulic circuits in the service manual.
Closed position
14
Fig. 2.11
2.7 Built in time switch A
The boilers are equipped with a built in electronic
time switch (5, Fig. 1.3 on page 2) which controls
the c.h. operation.
H
A
BCDEF
G
Fig. 2.12
Display and control panel
A Mode selector switch
B Reset button
C Enter button
D Increase “+” setting button
E Decrease “ --- ” setting button
F O n --- o f f b u t t o n
G Time display
H O N --- O F F d i s p l a y
Setting the current time
Note: with a new unit or when the reset button B
has been pressed and the selector switch A is to
the position, the time display G is flashing.
Set the mode selector switch A to the position
and press the buttons D or E until the current time
appears in the display G.
The clock starts by moving the switch A to the
AUTO position.
Setting example shown in Fig. 2.13:
Current time 16.30.
A
Fig. 2.13
Setting the switching time
20 memory locations are available, corresponding
to 10 on--- off sequences.
Set the mode selector switch A to the C1 position.
The symbols shown in Fig. 2.14 appears in the
display.
A
Fig. 2.14
Press the buttons D or E to set the desired ON
time.
Press the “enter” button C to confirm the setting
and to continue programming the OFF time.
SettheOFFtimeasexplainedabovefortheON
setting and confirm by pressing the “enter” button
C. Proceed in the same way for other settings.
Setting example shown in Fig. 2.15:
A --- ON time 7.45.
B --- OFF time 10.30.
USE

Instructions for use
8
AB
Fig. 2.15
Activating the timed settings
Set the mode selector switch A to the AUTO posi-
tion shown in Fig. 2.16.
The current time appears in the display. The ON---
OFF display H indicates the current state of oper-
ation (according to the settings).
A
Fig. 2.16
Note: when the mode selector switch A is in the
AUTO position and the boiler is switched off at the
fused spur isolation switch, the display H indicates
only the OFF state. The other indications are
blanked.
Reading the timed settings
Set the mode selector switch A to the C1 position.
The symbols shown in Fig. 2.14 appears in the
display.
Press the “enter” button C. Each time the button
is pressed the display shows the details of the next
setting.
Changing or deleting the timed settings
Set the mode selector switch A to the C1 position.
The symbols shown in Fig. 2.14 appears in the
display.
Press the “enter” button C until the display shows
the setting to be modified or deleted.
Thetimesettingcanbemodifiednowbypressing
button D or E and the operation can be switched
on or off by pressing the button F.
To delete a time set press the button D or E until the
symbols shown in Fig. 2.14 appears in the time
display G.
The new settings are memorized by moving the
switch A to a different position.
Manual operation
The operation of the time switch can be forced on
or off constantly or for a timed period.
To f o rce constantly on or off the timer operation
set the mode selector switch A to the TIMER posi-
tion. The symbols shown in Fig. 2.17 appears on
the display.
Fig. 2.17
The operation can be switched permanently on or
off by pressing the button F and leaving the switch
AintheTIMER position.
To f o r c e atimeddelayon or off operation, set the
mode selector switch A in the TIMER position.
Set the time delay by pressing the button D or E
and the operation can be forced on or off by pres-
sing the button F.
Thetimedelaycanbesetwithinthefollowing
ranges:
1to23hourswithstepsof1hour
1to27dayswithstepsof1day
The time delay setting is activated by moving the
switch A to the AUTO position.
The ON --- OFF display H flashes indicating that the
current state of operation has been forced.
To delete the timed delay setting, set the mode se-
lector switch A in the TIMER position, press the
button D or E until the symbols shown in Fig. 2.17
appears in the display and then set the mode se-
lector switch A to the AUTO position
Setting example shown in Fig. 2.18:
forced ON state for 4 hours.
Fig. 2.18
Resetting
To completely reset the timer, press the reset but-
ton with a pointed object (pencil).
CAUTION: pushing the reset button will complete-
ly erase the settings as well as all the data, includ-
ing the current time.
USE

Instructions for use
9
2.8 Built in time switch B
The combiboilers are equipped with a built in elec-
tronic time switch which controls the c.h. oper-
ation.
H
A
BCD EF
G
Fig. 2.19
Display and control panel
A Mode selector switch
B Reset button
C OK button
D Increase “+” setting button
E Decrease “ --- ” setting button
F O n --- o f f b u t t o n
G Time display
H O N --- O F F d i s p l a y
Setting the current time
Press repeatedly the button A until the display
shows the symbol
Press the buttons D or E until the current time ap-
pears in the display G.
The clock starts by pressing the button A to show
the symbol AUTO.
Setting example shown in Fig. 2.20:
Current time 16.30, day Thursday.
A
Fig. 2.20
Setting the switching time
28 memory locations are available, corresponding
to 14 on--- off sequences.
Press repeatedly the button A until the display
shows the symbol C1 (Fig. 2.21)
The symbols shown in Fig. 2.21 appears in the
display.
A
Fig. 2.21
Press the buttons D or E to set the desired ON
time.
Press the “OK” button C to confirm the setting and
to continue programming the OFF time.
SettheOFFtimeasexplainedabovefortheON
setting and confirm by pressing the “enter” button
C. Proceed in the same way for other settings.
Setting example shown in Fig. 2.22:
A --- ON time 7.45.
B --- OFF time 10.30.
AB
Fig. 2.22
Activating the timed settings
The current time appears in the display. The ON---
OFF display H indicates the current state of oper-
ation (according to the settings).
A
Fig. 2.23
Note: when the display shows the symbol AUTO
and the boiler is switched off at the fused spur
isolation switch, the display H indicates only the
OFF state. The other indications are blanked.
Reading the timed settings
USE

Instructions for use
10
Press repeatedly the button A until the display
shows the symbol C1 (Fig. 2.21)
The symbols shown in Fig. 2.21 appears in the
display.
Press the “OK” button C. Each time the button is
pressed the display shows the details of the next
setting.
Changing or deleting the timed settings
Press repeatedly the button A until the display
shows the symbol C1 (Fig. 2.21)
The symbols shown in Fig. 2.21 appears in the
display.
Press the “OK” button C until the display shows
the setting to be modified or deleted.
Thetimesettingcanbemodifiednowbypressing
button D or E and the operation can be switched
on or off by pressing the button F.
To delete a time set press the button D or E until the
symbols shown in Fig. 2.21 appears in the time
display G.
The new settings are memorised by pressing the
button A.
Manual operation
The operation of the time switch can be forced on
or off constantly or for a timed period.
To f o rce constantly on or off the timer operation
press repeatedly the button A until the display
shows the symbol TIMER. The symbols shown in
Fig. 2.24 appears on the display.
A
Fig. 2.24
The operation can be switched permanently on or
off by pressing the button F and leaving the dis-
play shows the symbol TIMER.
To f o r ce atimeddelayon or off operation, press
repeatedly the button A until the display shows the
symbol TIMER.
Set the time delay by pressing the button D or E
and the operation can be forced on or off by pres-
sing the button F.
Thetimedelaycanbesetwithinthefollowing
ranges:
1to23hourswithstepsof1hour
1to27dayswithstepsof1day
Press the button A until the display shows the sym-
bol AUTO.
The ON --- OFF display H flashes indicating that the
current state of operation has been forced.
To delete the timed delay setting, press repeatedly
the button A until the display shows the symbol
TIMER, press the button D or E until the symbols
showninFig.2.25appearsinthedisplayandthen
press the button A untilthe display shows the sym-
bol AUTO.
Setting example shown in Fig. 2.25:
forced ON state for 4 hours.
A
Fig. 2.25
Note:If during manual operation, power supply
turns off, timer must be set again following previ-
ous steps
Resetting
To completely reset the timer, press the reset but-
ton with a pointed object (pencil).
CAUTION: pushing the reset button will complete-
ly erase the settings as well as all the data, includ-
ing the current time.
USE

3USEFUL ADVICE
11
3.1 Central heating
For reasonably economical service install a room
thermostat.
Never shut off the radiator in the area where the
room thermostat is installed.
If a radiator (or a convector) does not heat up,
check that no air is present in it and that its valve
is open.
If the ambient temperature is too high, do not alter
the radiator valves. Reduce the central heating
temperature instead by means of the room ther-
mostat and the function selector (8 in Fig. 3.1).
8
Fig. 3.1
3.2 Frost protection
This appliance is provided with a built in anti---
freeze system that operates the boiler when the
temperature is below 5 ˚C
Therefore, when the boiler is not lit and used in
cold weather, with consequent risk of freezing do
not switch off the boiler at the fused spur isola-
tion switch or close the gas inlet cock.
3.3 Condensate drain
Thecondensatedrainmustnotbemodifiedor
blocked.
Blockage of the condensate drain, caused by de-
bris or freezing, can cause automatic shutdown of
the boiler.
If freezing is suspected and the pipe run is access-
ible an attempt may be made to free the obstruc-
tion by pouring hot water over the exposed pipe
an cleaning any blockage from the end of the
pipe. If this fails to remedy the problem the assist-
ance of a CORGI registered installer or in IE a com-
petent person should be sought.
3.4 Periodic maintenance
For efficient and continuous operation of the
boiler, it is advisable to arrange maintenance and
cleaning by an Authorised Service Centre En-
gineer, at least once a year.
During the service, the most important compo-
nents of the boiler will be inspected and cleaned.
This service can be part of a maintenance con-
tract.
In particular, you are advised to have the following
checks carried out:
--- primary heat exchanger;
--- domestic hot water heat exchanger;
--- burner;
--- exhaust fume duct and flue;
--- pressurisation of the expansion tank;
--- filling up of the central heating circuit;
--- bleeding of air from the central heating system;
--- general check of the appliance’s operation.
3.5 External cleaning
Before carrying out any cleaning, disconnect the
appliance from the electrical mains, using the
fused spur isolation switch fitted adjacent to the
appliance.
To clean the external panels, use a cloth soaked in
soapy water. Do not use solvents, abrasive powd-
ers or sponges.
Do not carry out cleaning of the appliance and/or
its parts with readily flammable substances (for
example petrol, alcohols, naphtha, etc.).
3.6 Operational faults
If the lock---out signal lamp comes on
this indicates that the safety lock ---out 6 (Fig. 3.2)
has stopped the boiler
To re--- start the boiler, it is necessary to press the
boiler reset button 7 (Fig. 3.2).
7
6
Fig. 3.2
For the first lighting up and following maintenance
procedures for the gas supply, it may be necess-
ary to repeat the resetting operation several times
so as to remove the air present in the pipework.
After five consecutive resetting attempts the reset
button is inhibited. To restore its function it is
necessary to switch the boiler off and on from the
USE

Useful advice
12
electrical mains, using the fused spur isolation
switch fitted adjacent to the appliance.
Safety lock--- out may occour even in case of an
blockage of the condensate drainage (e.g.
plugged drain pipe).
It is advisable to check the condensate drainage
pipe and traps for cleaness.
In case of persistent lock ---out call a competent
and responsible service engineer.
If noises due to air bubbles are heard during
operation...
you should check that the pressure on the tem-
perature and pressure gauge (Fig. 2.2 on page 4)
is not below the correct setting.
If required, top up the system correctly, as de-
scribed in the section 2.2 of this manual.
Bleed any air present in the radiators, if necessary.
If the pressure on the temperature and pres-
suregauge(4onpage2)hasgonedown...
it is necessary to top up the appliance with water
again, so as to raise the pressure to an adequate
level as described in the section 2.2 of this manual.
If topping up with water has to be done very fre-
quently, have the system checked for leaks.
If water comes out of the pressure relief valve
Check on the temperature and pressure gauge (4
on page 2) that the pressure in the central heating
circuit is not close to 3 bars. In this case, tempera-
ture rise in the circuit can cause the pressure relief
valve to open.
So that this does not happen and to decrease the
pressure to a normal value, it is advisable to vent
some of the water in the appliance through the
bleed valves present in the radiators.
If in time, a reduction in domestic hot water
supply is observed...
The likely causes may be impurities caught in the
domestic hot water flow switch filter or limescale
deposited in the domestic hot water heat ex-
changer. It is advisable to have the appliance
cleaned out by an Authorised Service Centre En-
gineer.
If water should occasionally leak from the
boiler...
shut off the valves positioned under the boiler
(Fig. 2.11 on page 7) and call an Authorised Ser-
vice Centre Engineer.
If the left appliance operation light 10 (Fig. 3.3)
flashes very quickly the boiler is detecting a
fault.
10
Fig. 3.3
In this case or in case of problems other than
those mentioned here, switch off the boiler, as
describedinsection2.6onpage6andcalla
competent and responsible service engineer.
USE

4TECHNICAL INFORMATION
13
4.1 Overview
24
43
42
41
40
38
39
26
2117
28
19
18
2731
20 22
23
25
303536
37
29
Fig. 4.1
11 Condensate drain pipe
12 C.h. return valve
13 Domestic cold water inlet valve
14 Gas inlet valve
15 D.h.w. outlet pipe
16 C.h. flow valve
17 Fan
18 Air pressure sensor test points
19 Air pressure sensor
20 Flue temperature probe NTC
21 Condensing heat exchanger
22 Safety thermostat
23 C.h. temperature probe NTC
24 Main circuit drain valve
25 Condensate trap
26 Automatic air purger valve
27 Pump vent plug
28 Pump
29 C.h. pressure relief valve
30 D.h.w. flow switch
31 Modulation gas valve
32 Modulation operator
33 Gas valve outlet pressure test point
34 Gas valve inlet pressure test point
35 D.h.w. temperature probe NTC
3 6 T h r e e --- w a y d i v e r t e r v a l v e
37 D.h.w. heat exchanger
38 Primary circuit pressure switch
39 Flame---detecting electrode
40 Burner
41 Ignition electrodes
42 Combustion chamber
43 Primary heat exchanger
44 C.h. expansion tank
4 5 B y --- p a s s v a l v e
46 Fan pressure connection
47 Domestic water circuit filter
48 D.h.w. flow limiter
49 Flue outlet pipe
50 Air intake pipe
INSTALLATION

Technical information
14
4.2 Main diagram
46
19
50
49
38
43
41
33
28
29
30
31
34
26
36
37
45
47
12 131614
44
17
39
23
35
15
32
22
40
24
48
21
25
11
20
Fig. 4.2
INSTALLATION

Technical information
15
4.3 Hydraulic specifications
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0 200 400 600 800 1000 1200 1400
0
10
20
30
40
kPa bar
l/h
60
50
Fig. 4.3
The hydraulic specifications in Fig. 4.3 represent
the pressure (available head for the central heat-
ing system) as a function of the flow rate.
The load loss due to the boiler has already been
subtracted.
Output with thermostat cocks shut off
The boiler is fitted with an automatic by --- pass
valve (45 on page 13), which protects the primary
heat exchanger.
In case of excessive reduction or total blockage of
water circulation in the central heating system
owing to closure of the thermostatic valves or sys-
tem component cocks, the by--- pass valve ensur-
es a minimum flow of water through the primary
heat exchanger.
4.4 Expansion vessel
Note: this boiler is designed for operation only
in a sealed central heating system
The height difference between the pressure relief
valve and the highest point in the system may be
10m at most.
For greater differences, increase the pre---load
pressure in the expansion vessel (44 on page 13)
and the system, when cold, by 0.1 bar for each
additional 1m.
For 24 Kw and 28 Kw
Capacity l6,0
P r e --- l o a d p r e s s u r e kPa
bar
100
1,0
Maximum volume of water
in the system *
l94
Ta b . 4 . 1
* Where conditions are:
--- Average maximum temperature of the system
is 85°C
--- Initial temperature when filling up the system is
10°C
For systems (24 Kw and 28 Kw) with volumes
greater than 94 l, an additional expansion vessel
must be provided.
INSTALLATION

Technical information
16
4.5 Technical data
mod. M96A.24SM/...
Heat input (A)
Nominal kW
BTU/h
25,0
85 295
Minimum kW
BTU/h
11,0
37 530
Useful output
Maximum kW
BTU/h
24,3
82 908
Minimum kW
BTU/h
10,5
35 825
Maximum condensing kW
BTU/h
26,0
88 708
Minimum condensing kW
BTU/h
11,2
38 213
Central heating
Maximum flow temp. ˚C85
Minimum flow temp. ˚C40
Minimum return temp. ˚C40
Maximum pressure kPa
bar
250
2,5
Minimum pressure kPa
bar
30
0,3
Available head
(in 1000 l/h)
kPa
bar
25
0,25
Seasonal efficiency
G20 (B) band
%
B
87,5
Seasonal efficiency
G30 G31 (B) band
%
B
88,4
Domestic hot water
Maximum temperature ˚C55
Minimum temperature ˚C35
Maximum pressure kPa
bar
1 000
10
Minimum pressure kPa
bar
30
0,3
Flow rate
minimum l/min 2,5
30˚rise (C) l/min 11,6
35˚rise (C) l/min 10,0
40˚rise (C) l/min 8,7
Gas supply pressures
Gas Natural
G20
Butane
G30
Propane
G31
Norm. Pa
mbar
2 000
20
2 900
29
3 700
37
Max Pa
mbar
2 500
25
3 500
35
4 500
45
Min. Pa
mbar
1 700
17
2 000
20
2 500
25
1 mbar approximately equals 10 mm H2O
(A) referred to the net calorific value at 15 ˚C and 1013,25 mbar
G 20 = 34,02 MJ/m3, G 30 = 45,6 MJ/kg, G 31 = 46,4 MJ/kg
(B)The value is used in the UK Government’s Standard Assessment Procedure (SAP) for energy rating
of dwellings. The test data from which it has been calculated have been certified by a notified body.
(C) Values subject to tolerance
INSTALLATION