Saunier Duval ISOFAST CONDENS F 35 E Operating manual

INSTRUCTIONS FOR USE, INSTALLATION AND SERVICING
FOR ISOFAST CONDENS F 35 E
3
4000135500-2 04/04
INSTRUCTIONS FOR USE
Lighting : make sure that:
•the boiler is connected
to the electrical supply,
•the gas service tap is open,
•Switch ON (I).
Switch off the boiler : Switch
to OFF (0) : the electrical
supply is off. Stop the gas
supply if the boiler is to be
out of use for a long time.
In case of fault, the
red warning light will flash
and a code appears
on the boiler display .
Code 21: Water pressure too
low: open the blue tap (t)
situated under the boiler until a
pressure of 1.5 bar is obtained.
Other codes: press the key of the
room thermostat and read the indications
given by the display.
Lighting/switch off the boiler
Fault indication
1-On/Off switch.
2-Room thermostat disabled when the
button light is ON
3-Sanitary function enabled when the
button light is ON
4-Heating function enabled when the
button light is ON
5-Hot water temperature adjuster.
6-Heating temperature adjuster.
7-Graphic display.
8-Green running light.
9-Red, flashing fault light.
10- Yellow running lamp for the burner.
1
➡
4
2
3
56
7
8910
Operation without room thermostat
• Press the key (the key will light-up)
• Press the and/or buttons to
activate the heating and/or hot water
functions
• Use buttons and to determine the
heating and hot water temperatures.
• To revert to the operating mode with room
thermostat, again press the key (the
light will turn OFF;
569
7
t
21
OK
2
Important notice : The settings performed
on the boiler control panel are not
transmitted to the room thermostat.
Perform the temperature settings from
the wireless room thermostat supplied
together with the boiler, strictly adhering
to the instructions given in this manual,
pages 10 through 17.
Contents
INSTRUCTION FOR USE
Controls and Lighting page 2
Important informations 3 - 5
Guarantee informations 6 - 7
Controls informations 8 - 17
INSTALLATION
INSTRUCTIONS
General informations 18
Dimensions 19
Technical Data 20 - 23
Boiler coponents 24
Schematic layout of boiler 25
Boiler location 26 - 27
Flue location and
Ventilation 28 - 31
Heating System 32 - 33
Domestic
Hot Water System 33
Boiler Installation 34
Piping installation 35 - 38
Electrical Connection 39
Commissioning
on boiler 40 - 43
Commissioning
on room thermostat 44 - 51
Gas conversion 52 - 53
SERVICING
INSTRUCTION
Routine Cleaning
and Inspection 54 - 59
Wiring Diagram 60 - 61
Fault Finding 61 - 63
Replacement of Parts 64 - 72
Spare Parts 73
Important information
The instructions consist of
three parts, User,
Installation and Servicing
Instructions, which
includes the Guarantee
Registration Card. The
instructions are an integral
part of the appliance and
must, to comply with the
current issue of the Gas
Safety (Installation and Use)
Regulations, be handed
to the user on completion
of the installation.
General
This combination boiler is
able to provide room heating
as part of a central heating
system, and domestic hot
water direct from the cold
water supply without the
need for secondary storage.
The central heating water
temperature and domestic
hot water temperature can
both be adjusted on the
boiler.
Once the controls are set
the boiler operates
automatically.
A frost protection program is
also included.
Please read these
instructions and follow them
carefully for the safe and
economical use of your
boiler.
Gas Category
This boiler is for use only on
Natural gas (G20) or
propane (G31).
Gas Safety (Installation
and Use) Regulations
In your own interests and
that of safety, it is the Law
that ALL gas appliances are
installed by a competent
person in accordance with
the current issue of the
above regulations.
Gas Testing and
Certification
The boiler is tested and
certificated for safety and
performance.
It is, therefore, important
that no alteration is made to
the boiler unless approved,
in writing, by Saunier Duval.
Any alteration not approved
by Saunier Duval, could
invalidate the certification,
boiler warranty and may also
infringe the current issue of
the statutory requirements.
CE Mark
This boiler meets the
requirements of Statutory
Instrument, No. 3083 The
Boiler (Efficiency) Regulations,
and therefore is deemed to
meet the requirements of
Directive 92/42/EEC on the
efficiency requirements for
new hot water boilers fired
with liquid or gaseous fuels.
Type test for purposes of
Regulation 5 certified by :
Notified body 0086.
Product/production certified
by : Notified body 0086.

USERS
54
Important information
The CE mark on this
appliance shows
compliance with :
1. Directive 90/396/EEC on
the approximation of the
laws of the Member States
relating to appliances
burning gaseous fuels.
2. Directive 73/23/EEC on
the harmonisation of the
Laws of the Member States
relating to electrical
equipment designed for use
within certain voltage limits.
3. Directive 89/336/EEC on
the approximation of the
Laws of the Member States
relating to electromagnetic
compatibility.
Control of Substances
Hazardous to Health
Under Section 6 of The
Health and Safety at Work
Act 1974, we are required
to provide information on
substances hazardous to
health.
The adhesives and sealants
used in this appliance are
cured and give no known
hazard in this state.
Insulation Pads
These can cause irritation to
skin, eyes and the
respiratory tract.
If you have a history of skin
complaint you may be
susceptible to irritation. High
dust levels are usual only if
the material is broken.
Normal handling should not
cause discomfort, but follow
normal good hygiene and
wash your hands before
eating, drinking or going to
the lavatory.
If you do suffer irritation to
the eyes or severe irritation
to the skin seek medical
attention.
Spare Parts
REMEMBER, When
replacing a part on this
appliance, use only spare
parts that you can be
assured conform to the
safety and performance
specification that we require.
Do not use reconditioned or
copy parts that have not
been clearly authorised
by Saunier Duval.
Manual Handling
Guidance
During the appliance
installation and the
replacement of the
heat exchanger it will be
necessary to employ caution
and assistance whilst lifting
as the appliance or
component exceeds the
recommended weight for a
one man lift.
In certain situations it may
be required to use a
mechanical handling aid.
Take care to avoid trip
hazards, slippery or wet
surfaces.
Gas Leak or Fault
If a gas leak or fault exists or
is suspected, turn the boiler
mains electrical supply off
and turn off the gas supply
at the meter. Consult your
local gas company or your
local installation/ servicing
company.
Electrical Supply Failure
The boiler must be earthed.
The boiler will not work
without an electrical supply.
Normal operation of the
boiler should resume when
the electrical supply is
restored.
Reset any external controls,
to resume normal operation
of the central heating.
If the boiler does not resume
normal operation turn the
mains reset switch off and
on. If the boiler does not
resume normal operation
after this the overheat stat
may have operated. The
overheat stat would only
operate under abnormal
conditions and, under these
circumstances; it would be
advisable to consult your
installation / servicing
company.
Boilers Installed in a
Compartment or Cupboard
If the boiler is fitted into a
compartment or cupboard,
it does not require any
ventilation openings. Do not
use the compartment
or cupboard for storage.
Pluming from flue terminal
Like all condensing boilers
this appliance will produce a
plume of condensation from
the flue terminal in cool
weather. This is due to the
high efficiency and hence
low flue gas temperature of
the boiler. It is normal and
not a fault indication.
Replacement Parts
If replacement parts are
required contact
Saunier Duval service using
the telephone number on
the back cover of this
booklet.
Please quote the name of the
appliance this infomation will
be on the front of the
appliance.
Protection Against Freezing
The room thermostat
automatically ensures a
minimum installation
temperature of 6°C.
This protection is ensured
by the room thermostat as
long as it is active. This
means that the button
of the boiler must not be lit
and that the batteries of the
room thermostat must be in
good condition.
If you are out of home for a
few days, use the holidays
mode of your room
thermostat, and set the Start
and End dates, as well as
the desired temperature.
If the mains electricity and
gas are to be turned off for
any long periods during
severe weather, it is
recommended that the
whole system, including the
boiler, should be drained to
avoid the risk of freezing.
Contact your
installation/servicing
company as draining, refilling
and pressurising MUST be
carried out by a competent
person.
As a safety feature the boiler
will stop working if the
condensate drain becomes
blocked. During freezing
conditions this may be
due to the forming of ice in
the condense drain external
to the house. Release an ice
blockage by the use of
warm cloths on the pipe.
The boiler should then
restart. Contact your
installation/servicing
company if the fault
persists.
Draining and Filling
This boiler works in a
pressurised system, which
must only be drained,
refilled and pressurised by a
competent person.
Pressure Relief Safety
Valve
A pressure relief safety valve
and discharge pipe is fitted
to the boiler. This valve must
not be touched. Should
there be any discharge from
the pipe, isolate the boiler
electrical supply and
call your installer or
Saunier Duval service using
the telephone number on
the back cover of this
booklet.
Access to the user menu :
+
OK
OK
HOLIDAYS START DATE
END DATE
CANCEL
MENU
+

To ensure the continued
efficient and safe operation
of the appliance it is
recommended that it is
checked and serviced as
necessary at regular
intervals. The frequency of
servicing will depend upon
the particular installation
conditions and usage, but in
general once a year should
be enough. Refer to Section
«Routine Cleaning and
Inspection».
If this appliance is installed
in a rented property there is
a duty of care imposed on
the owner of the property by
the current issue of the Gas
Safety (Installation and Use)
Regulations, section 35.
Servicing/maintenance
should be carried out by a
competent person in
accordance with the rules in
force in the countries of
destination.
To obtain service,
please call your installer or
Saunier Duval service using
the telephone number on
the back cover of this
booklet.
Please be advised that the
‘Benchmark’ logbook
should be completed by the
installation engineer on
completion of
commissioning and
servicing.
All CORGI Registered
Installers carry a CORGI ID
card, and have a registration
number. Both should be
recorded in your boiler
Logbook. You can check
your installer is CORGI
registered by calling CORGI
direct on: 01256 372300.
Cleaning
The boiler casing can be
cleaned with a damp cloth
followed by a dry cloth to
polish.
Do not use abrasive or
solvent cleaners.
Boiler casing
CAUTION. Do not remove
or adjust the casing in any
way, as incorrect fitting may
result in faulty operation. If in
doubt, consult your
installation/service company.
USERS
76
Servicing,
all you need to know
Many thanks for choising
Saunier Duval market
leaders in boiler
manufacture,
Your appliance is
guaranteed for a period of
24 months from the date
of installation or 30
months from the date of
manufacture whichever is
the shorter and covers
manufacturing defects only.
We, Saunier Duval,
undertake to repair or
replace parts free of charge
which are recognised by us
to be of faulty manufacture -
if necessary after return to
our factory for examination -
on condition that :
a) The appliance was
installed by a qualifled gas
installer in accordance with
installation instructions, and
all the relevant codes of
practice, standards and
legislation in force.
b) The appliance has been
used for normal domestic
purposes and in accordance
with the manufacturer's
operating and maintenance
instructions.
c) The appliance has not
been serviced, maintained,
repaired dismantled or
tampered with during the
guarantee period, by anyone
other than an engineer
approved by Saunier Duval.
d) The appliance is still in
the possession of the
original user, and proof of
purchase in the form of a
receipt or invoice is shown
to the service engineer on
request.
The repair or replacement of
parts during the guarantee
period does not have the
effect of extending the
period.
This guarantee does not
cover :
a) Any defects or damage
resulting from incorrect or
poor installation, inadequate
servicing, or maladjustment
of the gas or water used.
b) Any defects in the system
to which the appliance is
connected.
c) Any deterioration or
maladjustment following
changes in the nature or
pressure of the gas or the
water used, or a change in
the characteristics of the
electrical supply voltage.
Notification of any fault
should be made to the
appliance installer.
No repairs should be
undertaken upon the
Welcome users
appliance, intending it to be
covered by the product
guarantee without prior
authorisation from
Saunier Duval.
IMPORTANT : The
appliance serial number
must be quoted on all
correspondence/contact
made with Saunier Duval.
This guarantee is in
addition to your statutory
and other legal rights, which
will not be excluded or
diminished by the return
of the guarantee registration
card.

USERS
8 9
SYSTEM PRESSURE
TOO LOW
FILL IN AT 1,5 BAR
Ambient
temperature display
Time period for the
COMFORT temperature
Hot water
mode indicator
Heating mode
indicator
Time display Time period for the
ECO temperature
Low battery
indicator
1-Display.
2-Fault indicator.
3-Return to previous menu
4-Confirm OK.
5-Access to the menus.
6 - Menu scrolling
7-Changing the mode
8-Wall bracket
9-Mains power plug
1
2
34
5
6
7
8
9
Fault description Heating demand
indicator
Indicators of the
current temperature levels
for “COMFORT
or ECO”
(Day/Night).
(Attention: this value may
vary when you hold the
thermostat in your hand).
Your Isofast boiler is
factory set to operate within
a customary installation.
Nevertheless, as many
installations may
incorporate specific
features, feel free to contact
your installer who will be
able – by adapting the
parameters of the boiler
(maximum temperature
and/or maximum power of
the heating system) - to
warrant you the best
operating performance of
your installation.
These settings being made,
you still have the possibility
of selecting the ambient
temperature to suit your
own requirements not only
when you are at home, but
also during nightime or
when you are out
All these settings are
achieved from the room
thermostat supplied
together with your boiler: if
you accurately determine
the temperatures that best
suit to your needs, you will
make significant savings in
terms of gas consumption.
Control
as a source of savings
Essential adjustments to
the wireless room
thermostat :
A – Setting the time
B – Setting the date
The thermostat’s
weekly programme
functions enable you :
C – To activate or
deactivate the heating
function.
D – To have a standard
weekly programme by
activating the programme
pre-set at the factory.
E – To bypass the current
programme, temporarily,
to increase or lower the
temperature at any time
during the day.
F – To set up a custom
programme for each day of
the week, with 2
temperature levels, for
example:
• COMFORT for the periods
you are present and.
• ECO at night or when you
are away.
G – To have the same
temperature 24 hours a day
by deactivating the
programme.
H – To leave on holiday,
determining the desired
temperature according to the
date you leave and when
you return.
I – To select the temperature
of your domestic hot water
from 38°C to 60°C.
However, keeping the
temperature below 50°C,
reduces gas consumption
and provides good
protection against scalds.
J – To prevent undesired
alterations to your settings
by locking the thermostat’s
buttons.
K – To be informed of any
operating faults in the
boiler and be instructed in
the procedure to follow.

USERS
1110
• Exit from the menu by pressing , which initiates the standard weekly programme
pre-set at the factory :
C
C
Progress of the operations:
Activating the initial programme
Please note that pressing button
at any time takes you back to the previous step.
D
PROG
PROG
• When the ON mode appears, wait 5 seconds for the display to return to normal position
and automatically validate the selection.
PROGRAMME OFF
PROGRAMME ON
or
• Press , the room thermostat shows this display:
• Pressing reverses
ON and OFF mode every time
1 - Activating the weekly programme
2 -Accessing the initial programme
11 PM >> 6 AM>> 8 AM >> 4 PM >> 11 PM
ECO temperature 16°C COMFORT temperature 19°C
11 PM >> 7 AM >> 11 PM
ECO ECOCOMFORT COMFORT ECO COMFORT
Monday to Friday Weekends
OK
PROGRAMME INITIAL PROGRAMME
MONDAY OK
OK
+
SET COMFORT T¡
SET ECO T¡
PROGRAMME
...
• Press to select the
"Programme" menu :
MENU +
Temporarily bypassing the weekly programme
E
• Pressing one of the scroll buttons calls up the menu for setting the ambient temperature :
This setting is automatically cancelled when the programme changes to Eco or Confort temperature level.
OK
SET ROOM T¡
22¡C OK
SET ROOM T¡
Confirm by pressing
20¡C
OK
SET TIME 17:23 +OK
+OK
OK
SET DATE TUE 14/JUA/ 03
C
Progress of the operations : Please note that pressing button
at any time takes you back to the previous step
Settings for the time and the dateand
A B
SET COMFORT T¡
SET ECO T¡
PROGRAMME
SET HOT WATER T¡
ON/OFF HEATING
HOLIDAYS
SET TIME
SET DATE
• Press to call up the next menu:
• Use the buttons to select the "Set time" menu:
• Use the buttons to select the "Set date" menu:
MENU
1 - Accessing the user menu
2 - Setting the time
3 - Setting the date
Activating/deactivating the heating function
C
PROGRAMME
SET HOT WATER T¡
ON/OFF HEATING
...
• Press to select the "ON/OFF heating "
menu:
MENU
1 - Activate the heating
OK OK
ON/OFF HEATING ON
OFF
OK OK
ON/OFF HEATING ON OFF
2 - Deactivate the heating
+OK
Control
as a source of savings

USERS
1312
PROG
OK
MODIFY
COPY TO MONDAY
TUESDAY
MONDAY
TUESDAY OK OK OK
• Press to confirm the parameters you have set for the day.
• Follow the same procedure for every day of the week or use the duplication function,
as explained below.
19.5
MODIFY
TIME-SLOTS :
T¡ CHOICE : PROG
19.5 16.5
Press to switch from
COMFORT to ECO temperature This symbol indicates the
mode authorising deletion
of black squares to set up
operating periods at the
stated ECO temperature
using the buttons / .
E.g. :
In the case of the
illustration opposite, each
press of the button
adds a blank from 6 AM
onwards, corresponding to
an extra 30 minutes
heating at 16.5°C.
E.g. :
In the case of the
illustration opposite, each
press of the button
adds a square from 11
PM onwards,
corresponding to an extra
30 minutes heating at
19.5°C.
This symbol indicates the
mode authorising additional
operating periods at the
stated COMFORT
temperature (black
squares)
using the buttons / .
The squares indicate
the time periods when the boiler will
provide the COMFORT temperature
level
(e.g.: 19.5°C between 4 PM and 11
PM and 6 AM and 8 AM)
The blanks indicate
the time periods when the boiler will
provide the ECO temperature level.
(e.g.: 16.5°C between 8 AM and 4
PM and 11 PM and 6 AM)
Duplicating a programme
• To save time, you can copy the parameters you have set onto another day via the menu :
/
MODIFY
TIME-SLOTS :
T¡ CHOICE : PROG / MODIFY
TIME-SLOTS :
T¡ CHOICE : PROG /
23:00 6:00
Control
as a source of savings
OK OK
SET COMFORT T¡
SET COMFORT T¡
SET ECO T¡
PROGRAMME
...
19.0¡C 19.5¡C
18.5¡C
20.0¡C
OK
PROGRAMME MODIFY
COPY TO
MONDAY
TUESDAY
WEDNESDAY
THURSDAY
FRIDAY
SATURDAY
SUNDAY
INITIAL PROGRAMME
OK OK
/...
/...
(to set the desired temperature during the day)
(to set the desired temperature
during the night or while you are away)
OK OK
SET ECO T¡ 16.0¡C 16.5¡C
16.0¡C
17.0¡C
/...
/...
(to allocate time periods for the
Comfort and Eco temperatures)
PROG
PROG
• When the ON mode appears, wait 5 seconds for the display to return to normal position
and automatically validate the selection.
PROGRAMME OFF
PROGRAMME ON
or
C
• Press to call up the next menu:
• Press , the room thermostat shows this display:
• Pressing
reverses ON and OFF mode every time.
Progress of the operations :
MENU
Setting the custom weekly programme
1 - Activating the weekly programme
2 - Access to the user menu
3 - Setting the Comfort temperature
4 - Setting the Eco temperature
5 - Programme
Please note that pressing button
at any time takes you back to the previous step.
F

USERS
1514
SET ECO T¡
PROGRAMME
SET HOT WATER T¡
...
OK OK
SET HOT WATER T¡ 50¡C 51¡C
49¡C
52¡C
/....
/....
(to set the hot water to
the desired temperature)
C
• Press to call up the next menu :
Progress of the operations :
MENU
Setting the hot water temperature
1 - Access to the user menu
2 - Setting the hot water temperature
Please note that pressing button
at any time takes you back to the previous step.
+
I
Locking/unlocking the thermostat’s buttons
J
• Holding down the and buttons simultaneously for 3 seconds locks the room
thermostat’s buttons.
• Follow the same procedure to unlock the buttons.
Press for 3 seconds
COK
OK OK
SET ROOM T¡
SET ROOM T¡
...
19.0¡C 19.5¡C
18.5¡C
20.0¡C
/...
/...
(to set the constant
temperature desired)
PROG
C
• Press to call up the next menu :
• Pressing activates or deactivates the programme mode each time :
• Retain the PROGRAMME OFF position. After 5 seconds, the display returns to its normal position
and automatically validates this selection.
Progress of the operations :
MENU
Setting the heating temperatures outside Programme mode
1 - Deactivating the weekly programme
2 - Access to the user menu
3 - Setting the ambient temperature
Please note that pressing button
at any time takes you back to the previous step.
PROGRAMME ON PROGRAMME OFF
PROG PROG
G
Control
as a source of savings
SET HOT WATER T¡
ON/OFF HEATING
HOLIDAYS
...
HOLIDAYS
• Press to call up the next menu :
• Determine the temperatures you wish according to your departure and return dates.
MENU
Holiday programme
1 - Access to the user menu
2 - Activating the Holiday programme
+
H
+
OK
OK
START DATE
END DATE
SET ROOM T¡
CANCEL

USERS
1716
Glossary
for the user menu
Control
as a source of savings
• If a fault occurs, the red lights on the boiler and on the room thermostat flash
and a pictogram is displayed on the thermostat : , , , or
• Press the button on the thermostat:
• The thermostat shows the procedure to follow:
• At the same time, the boiler’s screen shows
the code for the fault:
• The thermostat asks you to call your After-Sales service
engineer, informing him of the fault code flashing on the boiler
to assist in his diagnosis.
• At the same time, the boiler’s screen
shows the code for the fault:
Fault indicators
Fault level 1
Fault level 2
21
23
SYSTEM PRESSURE
TOO LOW
FILL IN AT 1.5 BAR
FLOW RATE FAULT
CALL AFTERSALES
TEL [phone]
OK
K
Setting the ambient temperature when the programme has
not been activated (Programme inactive).
Setting the Confort temperature for the periods set in
“Programme” menu.
Setting the reduced temperature for the periods set in the
“Programme” menu.
Allocating operating periods for Confort and Eco
temperature for each day of the week. In the morning, for
example, you are recommended to start heating
approximately 1 hour before you get up.
Displaying the external temperature when an external
sensor is installed.
Setting the hot water temperature.
Starting / stopping heating
On = Heating + hot water
Off = Hot water only
Outdoor T° = displayed when an external sensor is
connected. When “Driven by ext. T°” is
selected, the boiler automatically cuts off the
heating when the temperature is higher than
18°C (factory setting).
Displayed if your installer has selected "consigne
”manual“ in the “heating control” menu under the
“installer” menu
Setting the ambient temperature for while you are
away.
Setting the time.
Setting the date.
Set room T°
Set comfort T°
Set eco T°
Programme
Outdoor T°
Set hot water T°
ON/OFF heating
Set radiator T°
or
Floor heating T°
Holidays
Set time
Set date

INSTALLERS
1918
Dimensions
The boiler is delivered in
one package :
the boiler itself, the wireless
thermostat, the fixing
bracket, the template and
pipe connections .
The different packages
relating to the flue system
will be ordered depending
on the actual configuration
of the installation
418
890
510
232
Isofast F 35 E
Net weight (kg) 52
Gross weight (kg) 60
The “as delivered” package consists of :
- 1 wireless thermostat
- 1 fixing bracket
- 3 x 1.5 V alkaline battery cells type LR6
- 1 access cover to the battery cells
ATTENTION: DO NOT FORGET TO RECOVER
THE ROOM THERMOSTAT placed in a
polystyrene case in the bottom of the package.
General Information
IMPORTANT NOTICE
The boiler and pipes are
supplied in one pack, the
flue is supplied seperately.
This boiler is factory set for
use only on G20 natural
gas.
Where no British Standards
exists, materials and
equipment should be fit for
their purpose and of suitable
quality and workmanship.
Refer to Manual Handling
Operations, 1992
regulations.
The installation of this boiler
must be carried out by a
competent person in
accordance the rules in
force in the countries of
destination.
Manufacturer’s instructions
must not be taken as
overriding statutory
requirements.
Sheet Metal Parts
WARNING: When installing
the appliance, care should
be taken to avoid any
possibility of personal injury
when handling sheet metal
parts.
Statutory Requirements
The installation of the boiler
MUST be carried out by a
competent person in
accordance with the relevant
requirements of the current
issue of : Manufacturer’s
instructions, supplied.
The Gas Safety (Installation
and Use) Regulations, The
Building Regulations, The
Building Standards
(Scotland) Regulations
(applicable in Scotland),
local Water Company
Bylaws, The Health and
Safety at Work Act, Control
of Substances Hazardous
to Health, The Electricity at
Work Regulations and any
applicable local regulations.
Detailed recommendations
are contained in the current
issue of the following British
Standards and Codes of
Practice, BS4814, BS5440
Part 1 and 2, BS5449,
BS5546, BS6700, BS6798,
BS6891 and BS7074 Part 1
and 2, BS7478, BS7593,
BS7671.
We also suggest that you
have to hand a copy of the
British Gas publication,
“Guidance Notes for the
Installation of Domestic
Condensing Boilers”.
Manufacturer’s notes must
not be taken as overriding
statutory obligations.
Certification
This boiler certificated to the
current issue of EN 483 for
performance and safety.
It is important that no
alteration is made to the
boiler, without permission, in
writing, from Saunier Duval.
Any alteration that is not
approved by Saunier Duval.,
could invalidate the warranty
and could also infringe the
current issue of the
Statutory Requirements.
Electrical Supply
All system components shall
be of an approved type and
all wiring to current I.E.E.
wiring regulations.
External wiring must be
correctly earthed, polarised
and in accordance with the
relevant standards.
In GB this is BS 6891.
In IE this is the current
edition of I.S.813 "Domestic
Gas Installations".
The boiler must be
connected to a permanent
230V ac, 50Hz supply.
Connection of the whole
electrical system of the
boiler, including any heating
controls, to the electrical
supply must be through one
common isolator and must
be fused 3 Amp maximum.
Wiring to the boiler must be
PVC 85°C insulated cable,
not less than 0.75mm2
(24/0.20mm).

INSTALLERS
2120
Natural Gas (G 20) F 35 E
Ø burner injector (mm) 5,65
inlet pressure (mbar) 20
Sanitary flow rate at maximum input (m3/h) 3,62
Heating flow rate at maximum input (m3/h) 3,02
Flow rate at minimum input (m3/h) 0,85
Electricity F 35 E
Electrical supply (V) 230
Electrical rating (A) 0,9
Maximum absorbed power (W) 206
IP classification IPX4D
Class 1
Technical Data
Isofast
Heating F 35 E
Heating output at 80°C/60°C (P) adjustable (kW) from 7,6 to 28
(BTU/H) from 25,930 to 95,536
Heating input min. (Q) (kW)/(BTU/H) 8 / 27,296
Heating input max. (Q) (kW)/(BTU/H) 28,6 / 97,583
SEDBUK efficiency (%) ?
Heating output at 50°C/30°C adjustable (kW) from 8,6 to 30,6
Maximum heating temperature (°C) 80
Minimum heating temperature (°C) 22
Expansion vessel charge pressure (bar) 0,5
Maximum system capacity at 75°C (l) 215
Safety valve, maximum service pressure (PMS) (bar) 3,0
Hot water F 35 E
Heating output (P) adjustable from… (kW)/(BTU/H) 34,2 / 116,690
to… (kW)/(BTU/H) 7,6 / 25,931
Maximum hot water temperature (°C) 60
Threshold flow rate (l/min.) 1
Specific flow rate (D) (for 30°C temp rise) (l/min.) 16,3
Storage capacity (l) 4
Expansion valve setting (bar) 10
Minimum operating pressure (bar) 0,7
Maximum operating pressure (PMW)(bar) 10
Combustion F 35 E
Product outlet diameter (mm) 60
Fresh air inlet diameter (mm) 100
Fresh air flow rate (1013 mbar - 0°C) (m3/h) 43
Product outlet flow rate (g/s) 15,3
Product outlet temperature (°C) 68
Values of product outlet CO (ppm o mg/kWh) 100 or 176
CO2 (%) 9,2
NOx (ppm o mg/kWh) 21,1 or 37,3
Gas Supply
The gas installation must be
in accordance with the
relevant standards.
In GB this is BS6891.
In IE this is the current
edition of I.S.813 "Domestic
Gas Installations".
The supply from the
governed meter must be of
adequate size to provide a
steady inlet working
pressure of 20mbar (8in wg)
at the boiler.
On completion, test the gas
installation for soundness
using the pressure drop
method and suitable leak
detection fluid, purge in
accordance with the above
standard.
Technical Data
All dimensions are given in
millimetres (except as
noted).
The data label is positioned
on the inner door.
The Seasonal Efficiency
Domestic Boilers UK
(SEDBUK) is Band 'A'.
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 has been certified
by B.S.I.
F 35 E
Gas category II2H3P

INSTALLERS
2322
By-pass fully shut
Open 1/2 turn
By-pass fully shut
Open 1/4 turn
Open 1/2 turn
Open 2 turns
1
2
NB : Factory seeting : Speed II
III II I
Speed III
Bypass
The Isofast boiler has a
built-in bypass. This must
be adjusted according
to the requirements of the
system, refer to the flow
rate pressure curve.
The boiler is supplied with
the built-in bypass open
a half a turn. It is
adjusted by turning the
bypass screw (a).
Turn the screw clockwise
to close the bypass.
When using thermostatic
radiator valves (TRV’s)
on all of the radiators, it is
essential that a separate,
adjustable bypass of 15 mm
minimum diameter is fitted
between the flow and return
of the heating circuit.Any
bypass must be fitted before
system controls.
a
By-pass fully shut
Open 1/4 turn
Open 1/2 turn
70
60
50
40
30
20
10
500 14001000
2
3
9
7
8
6
1
4
5
Curve output/pressure
Available pressure (kPa)
between heating supply and return lines
Flow rate through heating system (l/h)
Technical Data
Speed II
Speed I
3
4
5
6
7
8
9

INSTALLERS
2524
1
3
22
AB C DE
2
89
7
10
14
13
12
11
19
24
15
16 17 18
20 21 23
25 26 27
28
29 30 31 32
6
3
45
Isofast F 35 E
Schematic layout of boiler
1-Flue outlet
2-Main heat exchanger
3-Burner
4-Ignition and controle
electrode
5-Fan
6-Gas control valve
7-DHW storage vessel
8-Condensate drain
9-Overheat safety
thermostat.
10 - Temperature sensor for
DHW storage vessel
11 - Expansion vessel
12 - Heating return
thermistor
13 - Heating outlet
thermistor
14 - Ignition module
15 - Pump
16 - Water pressure sensor
17 - Domestic plate to plate
heat exchanger
18 - Three way valve
19 - Heating element
20 - Drain cock
21 - Water flow sensor
22 - Discharge safety valve
3 bars
23 - DHW temperature
sensor
24 - Discharge safety valve
10 bar
25 - Isolating valve
26 - Filter on cold water inlet
27 - Filling system
28 - Filter on heating circuit
29 - Isolating valve
30 - Isolating valve
31 - Isolating valve
32 - Isolating valve
A-Heating return
B-Cold water inlet
C-Heating flow
D-Domestic hot water
outlet
E-Gas
a-Flue outlet
b-Overheat safety
thermostat.
c-Combustion chamber
d-Expansion vessel
e- Air/Gas mixture inlet
f-Ignition and control
electrode
g-Fan
h-Gas control valve
i-Ignition module
j-Condensate drain
k-Heating flow
thermistor
l-Heating return
thermistor
m-Water flow sensor
n-Water pressure sensor
o-Pump
p-Filter on cold water
inlet
q-Domestic plate to plate
heat exchanger
r-Discharge safety valve
10 bar
s-Discharge safety valve
3 bar
t-Filling system
u-Drain cock
v-Room thermostat plug
w-Control panel
Boiler components
Isofast F 35 E
a
bcd
f
e
j
k
l
m n q
r
tu
v
w
gh
i
s
op

INSTALLERS
2726
installed in a timber frame
building it should be fitted in
accordance with the
Institute of Gas Engineers
document IGE/UP/7/1998.
If in doubt seek advice from
the local gas undertaking or
Saunier Duval.
• The boiler is room sealed,
so when it is installed in a
room or space, a permanent
air vent is not required.
• Due to the high efficiency
and hence low casing
temperature of this boiler,
cupboard or compartment
ventilation is not necessary.
Boiler location
• This boiler is not suitable
for outdoor installation.
• This boiler may be
installed in any room,
although particular attention
is drawn to the installation of
a boiler in a room containing
a bath or shower where
reference must be made to
the relevant requirements.
In GB this is the current
I.E.E. WIRING
REGULATIONS and
BUILDING REGULATIONS.
In IE reference should be
made to the current edition
of I.S.813 "Domestic Gas
Installations" and the current
ETCI rules.
• The boiler should be
positioned so that at least
the minimum operational
and servicing clearances are
provided, see diagram
opposite.
Additional clearances may
be beneficial around the
boiler for installation and
servicing.
For flue installations where
external access is not
practicable, consideration
should be given for the
space required to insert the
flue internally, which may
necessitate clearance larger
than those specified in
diagram.
• If the boiler is to be
Leave existing air vents.
A template is supplied with
the fixing bracket.
Position setting of the
assembly shall be
performed in compliance
with the indications shown
on the template.
Use two or three screws for
the fixing bracket.
The mechanical
characteristics of the screws
shall – at least – meet the
requirements specified on
the sketches below. Also,
they shall be suited to the
characteristics of the carrier
wall.
16 kg mini
33 kg mini
16 kg mini
33 kg mini
If the boiler is not
immediately installed,
protect the different
couplings so that no plaster
or paint could jeopardize the
tightness of subsequent
connections.
232
GAS
70 102 70
2
115
20 mini
160
11875066
160
Ø 105
890
510

INSTALLERS
2928
Flue location and Ventilation
Flue Position and Length
The standard horizontal flue
is fitted onto the top of the
boiler using the flue elbow.
See diagrams to determine
whether a standard flue can
be used.
An elevated flue system can
be installed with the addition
of a vertical flue adapter,
extension kits and elbow,
see section flue options.
When extension pipes are
used the flue system must
be designed to have a
continuous fall to the boiler
of at least 3% to allow
condensate to run back into
the boiler and out via the
drain.
Internal Flue Installation
The flue can be installed
from inside the building,
when access to the outside
wall face is not practicale.
Additional accessories are available.
See Saunier Duval "Flue Options Guide" for
configurations available.
Minimum siting dimensions for fanned flues terminals
poritions
Horizontal flues
A-directly below an opening, air brick,
opening windows . . . . . . . . . . . . . . . . . . . . . . . . .300
B-above an opening, air brick, opening windows . . . .300
C - horizontally to an opening, air brick,
opening windows . . . . . . . . . . . . . . . . . . . . . . . . .300
D-below gutter, drain/soil pipe . . . . . . . . . . . . . . . . . . .25
E-below eaves . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
F-below a balcony or car port . . . . . . . . . . . . . . . . . .25
G- from vertical drain pipes and soil pipes . . . . . . . . . .25
H- from internal/external corners . . . . . . . . . . . . . . . . .25
H*- to a boundary alongside the terminal . . . . . . . . . . .300
I-above adjacent ground or balcony level . . . . . . . . .300
J-from surface or a boundary facing the terminal . . .600
K-facing terminals . . . . . . . . . . . . . . . . . . . . . . . . .1200
L-from opening (door/window) in car port
into dwelling . . . . . . . . . . . . . . . . . . . . . . . . . . . .1200
M - vertical from a terminal . . . . . . . . . . . . . . . . . . . .1500
N - horizontally from a terminal . . . . . . . . . . . . . . . . . .300
Vertical flues
P-from another terminal . . . . . . . . . . . . . . . . . . . . . .600
Q- above roof level . . . . . . . . . . . . . . . . . . . . . . . . . . .300
R-from adjacent opening window . . . . . . . . . . . . . .1000
S-from adjacent wall to flue . . . . . . . . . . . . . . . . . . . .300
H* and J* : These dimensions comply with the building regulations, but they may need to
be increased to avoid wall staining and nusance from pluming depending on site conditions.
Warning notice :
Use only flue accessories
developed for
Saunier Duval condensing
boilers.

INSTALLERS
3130
Flue location and Ventilation
• Terminal Position
The minimum acceptable
siting dimensions for the
terminal from obstructions,
other terminals and
ventilation openings are
shown in page 29. For
Ireland the minimum
distances for flue terminal
positioning must be those
detailed in I.S.813 "Domestic
Gas Installations".
The terminal must be
exposed to the external air,
allowing free passage of air
across it at all times.
Being a condensing boiler
some pluming may occur
from the flue outlet. This
should be taken into
consideration when
selecting the position for the
terminal.
It may be necessary to
increase dimensions H & J if
there is a risk that the boiler
products could stain any
adjoining surface.
Carports or similar
extensions of a roof only, or
a roof and one wall, require
special consideration with
respect to any openings,
doors, vents or windows
under the roof. Care is
required to protect the roof if
made of plastic sheeting. If
the carport comprises of a
roof and two or more walls,
seek advice from the local
gas supply company before
installing the boiler.
• Terminal Guard
A terminal guard is required
if persons could come into
contact with the terminal or
the terminal could be
subject to damage.
If a terminal guard is
required, it must be
positioned to provide
minimum of 50mm
clearance from any part of
the terminal and be central
over the terminal.
3%
The flue system pipes must
feature a slope of 3%
towards the boiler in order
to recover any condensates.
Attention : The flue system
terminal supplied by Saunier
Duval already integrates this
slope. Therefore, it shall be
applied to any flue system
extensions.
L
64
Gasket
The maximum head loss
is reached with an elbow
and flue system length (L)
of 10 m.
Horizontal flues (installation type C13)

INSTALLERS
3332
Heating system
General
The boiler is for use only
with sealed central heating
systems.
The safety valve is an
integral part of the boiler
and it cannot be adjusted.
The digital readout on the
controls fascia indicates the
system pressure when there
is no central heating
demand.
The circulation pump is
integral with the boiler.
Expansion vessel
The boiler has an integral
expansion vessel with a
capacity of 10 litres, with a
charge pressure of 0.5 bar.
Note : The expansion vessel
volume depends on the total
water system volume and
the initial system design
pressure. Guidance on
vessel sizing is also given in
the current issue of BS5449
and BS7074 Part 1, for IE
refer to the current edition of
I.S.813 "Domestic Gas
Installations".
Flow rate
If it is necessary to alter the
flow rate, the system can be
fitted with a lockable balancing
valve in the main flow or
return pipes shown as valve
"A" in diagram.
The flow rate through the
boiler must not be allowed
to fall below 14 l/min.
Bypass
The boiler is fitted with an
adjustable automatic
bypass. Ensure that under
no circumstances does the
flow rate drop below
14l/min.
The installation of the boiler
must comply with the
requirements of the current
issue of BS6798, in Ireland,
refer also to the current
edition of I.S.813 "Domestic
Gas Installations".
In GB it is necessary to
comply with the Water
Supply (Water Fittings)
Regulations 1999 (for
Scotland, the Water
Byelaws 2000, Scotland).
To comply with the Water
regulations your attention is
drawn to : The Water
Regulations guide published
by the Water Regulations
Advisory Service (WRAS)
gives full details of the
requirements.
Heating system
In IE the requirements given
in the current edition of
I.S.813 "Domestic Gas
Installations" and the current
Building Regulations must
be followed.
Water tratment
In the case of an existing
installation, it is ESSENTIAL
that prior to installing the
new boiler the system is
thoroughly flushed. For
optimum performance after
installation of a new system,
the boiler and its associated
central heating system
should also be flushed.
Flushing should be carried
out in accordance with
BS7593: 1992 using a
cleanser such as Sentinel
X300 or X400, Fernox
Superfloc or Salamander
corrosion guard cleaner.
For long-term corrosion
protection, after flushing, an
inhibitor suitable for stainless
steel heat exchangers
should be used, refer to the
current issue of BS 5449
and BS 7593 on the use of
inhibitors in central heating
systems. Examples are
Sentinel X100 Fernox or
Salamander corrosion guard
inhibitor.
Draining Tap
A draining tap must be
provided at the lowest
points of the system, which
will allow the entire system
to be drained.
A drain tap for the appliance
is provided as an integral
part of the hydroblock, see
diagram page 24.
General - All domestic hot
water circuits, connections,
fittings must be in
accordance with the
relevant standards and
water supply regulations.
Domestic Hot Water
System
For GB: Guidance G17 to
G24 and recommendation
R17 to R24 of the Water
Regulations Guide.
For IE: The current edition of
I.S.813 "Domestic Gas
Installations".
Water Pressure
The maximum working
pressure of the domestic
hot water circuit is 10 bar. If
the cold water supply
pressure exceeds this, then
a pressure-reducing valve
must be fitted in the supply
to the boiler.
'Hard' Water Areas
The temperatures within the
heat exchanger are limited
by the boiler control system
to minimise scale formation
within the hot water pipework.
However, in areas where the
water is 'hard' (i.e. more
than 200mg/litre), it is
recommended that the hot
water setting is reduced and
that a scale reducer is fitted.
Refer to the manufacturer's
instructions or consult the
local water company for
additional advice.
Domestic Water Flow Rate
The water flow rate is
restricted to a maximum 16
l/min by a restrictor fitted on
the cold water inlet.

INSTALLERS
3534
2
Boiler
installation
Prior to performing any
operation, it is essential that
the piping systems be
flushed with a suitable
product in order to eliminate
any impurities such as
fillings, weld spatters, oils
and greases.
Such foreign materials could
be driven into the boiler, and
could impair its operation.
NB: Solvents may cause
damages to the piping
system.
Remove the wooden beam
placed behind the boiler.
Appliance Connection
IMPORTANT: With regards
to the Manual Handling
Operations, 1992
Regulations, the following lift
operation exceeds the
recommended weight for a
one man lift, refer to Manual
Handling section, on page 4.
The appliance will contain a
small amount of water,
place a water container
beneath the boiler
connections before
removing the protective
caps.
1 - Lifting the boiler into
position, lean the top of the
boiler slightly to the wall and
position just above the
hanging bracket.
2 - Lower the boiler slowly
and engage onto the
hanging bracket.
Connect isolating valves
using washers and domestic
flow restrictor supplied with
the boiler.
3 - Do not forget to connect
the blue extension on the
filling tap, as shown on the
picture below.
1
➡
➡
3
A
BCD
E
GAS
70 70 115
250
223
WALL
102
u
t
v
w
x
Piping
installation
Make connections to boiler, gas, water and heating cocks with the tube assemblies
supplied in piping pack as shown in the diagram below :
A-Heating return with isolating tap (t) and (u),
B-Cold water inlet with isolating tap (v) and water restrictor to 16 l/min,
C-Heating flow with isolating tap (w),
D-Domestic hot water outlet,
E-Gas inlet with isolating tap (x).
Water restrictor
16 l/min.
Pressure connection
Gas Connection
Before connection check
supply of local gas.
Refer also to page 18.
Do not subject the gas
service cock to heat.
Fit the sealing washer into
the union nut and make
good the connection to the
gas service cock on the
wall.
Make sure the on / off lever
is accessible.
The whole of the gas
installation, including the
meter, should be inspected,
tested for soundness and
purged in accordance with
the current issue of BS6891
and in IE the current edition
of I.S.813 "Domestic Gas
Installations".
A - C : Central heating
Ø 22 mm
B-D : Domestic hot
water Ø 15 mm
E : Gas supply Ø 15 mm

INSTALLERS
3736
Water Connections
Flush out the domestic hot
water and the heating
systems before connecting
to the boiler.
Make the connections to the
domestic hot water and
heating systems by fitting
the sealing washers into the
securing nuts and make
good the connection to the
isolating valves.
Do not subject the isolation
valves to heat.
Make sure the drain point is
accessible.
• The heating return
coupling is equipped with a
filter, accessible after
removing the end nut.
•The proof-test pressure can
be read on a pressure gauge
screwed instead of the
heating return coupling end
nut (A).
u
A
t
Filter on heating
return (A)
A pressure gauge can be
screwed instead of the
heating return coupling
Piping
installation
Safety Discharge Valve
The pipes from the safety
discharge valves S1 and S2
must not discharge above
an entrance, window or any
type of public access area.
Take the short safety
discharge tube, union nut
and seal, supplied loose in
the boiler fittings pack and
fit as shown in diagram
below.
This must be extended,
using not less than 15mm
o.d. pipe, to discharge, in a
visible position, outside the
building, facing downwards,
preferably over a drain.
The pipe must have a
continuous fall and be
routed to a position so that
any discharge of water,
possibly boiling, or steam
cannot create any danger to
persons, damage to
property or external
electrical components and
wiring.
To ease future servicing it is
advisable to use a
compression type fitting
supplied with the boiler to
extend the safety discharge
valve tube.
s2
s1

39
WARNING : This appliance
must be earthed.
This appliance must be
wired in accordance with
these instructions. Any fault
arising from incorrect wiring
cannot be put right under
the terms of the
Saunier Duval guarantee.
All system components
must be of an approved
type.
Electrical components have
been tested to meet the
equivalent requirements of
the BEAB.
Do not interrupt the mains
supply with a time switch or
programmer.
Connection of the whole
electrical system and any
heating system controls to
the electrical supply must be
through a common isolator.
Isolation should preferably
be by a double pole
switched fused spur box
having a minimum contact
separation of 3mm on each
pole. The fused spur box
should be readily accessible
and preferably adjacent to
the boiler. It should be
identified as to its use.
Mains Cable
Important: If a replacement
supply cable is required it
must be purchased from
Saunier Duval.
• The 630 mA fuse of the
PCB must be connected to
the neutral.
Electrical
connection
INSTALLERS
38
Connect the A elbow
Ø 22 mm to a discharge
system leading to the
sewer, in compliance with
the instructions below:
- Use a rigid PVC tube or a
flexible silicon pipe resistant
to condensate.
- The pipe must have a
continuous fall.
- Do not use copper pipes
Important notice :
The float of the condensate
recovery system also
ensures fume tightness.
Therefore, it is useless to
add water in the
condensate box.
Condensate
discharge
elbow.
Condensate box with
access plugs for cleaning
purposes.
Ø 22 mm
A
NO YES
Piping
installation