Saunier Duval ISOMAX F 28 E User manual

1
THIS IS A CAT I2E+ APPLIANCE
01773 828100
IN WARRANTY
TECHNICAL HELPLINE
01773 828400
ISOMAX

2
INSTALLATION AND OPERATING INSTRUCTIONS
ISOMAX F 28 E
Note!
The boiler serial number is marked on the label attached to the inside of the drop down door. Refer to the
'Introduction' section page 3 for a description of the basic functions of the boiler. The 'Users' section
describes how to safely operate the boiler.
INSTALLATION SECTION
Introduction.................................................... Page 3
Commissioning..........................................................3
Controls & lighting ....................................................4
Control options .........................................................5
Draining .....................................................................5
Servicing/maintenance ..........................................5
Introduction.................................................. Page 3
Technical data ...................................................... 6
Dimensions ............................................................. 7
Heating system design ......................................... 7
Domestic hot water system design..................... 8
Boiler schematic .................................................... 8
Fixing jig .................................................................. 9
Piping system installation............................... 9 - 10
Boiler location ...................................................... 11
Boiler installation.................................................. 12
Flue installation ............................................. 12 - 13
Electrical installation ........................................... 14
Commissioning.............................................. 15 - 18
Safety devices .............................................. 18 - 19
Settings.................................................................. 20
USERS SECTION
Mandatory warning for CEE countries
Warning: This appliance is designed, approved and inspected to meet the requirements of the English
market. The identification plate located on the inside of the appliance certifies the origin where the
product was manufactured and the country for which it is intended.
If you see any exception to this rule, please contact your nearest Saunier Duval dealer.
Thank you in advance for your assistance.
Routine cleaning and inspection ........................... Page 21 - 22
Replacement of parts ......................................................... 22 - 26
Boiler schematic .......................................................................... 27
Technical data ............................................................................ 28
Schematic wiring diagram ........................................................ 29
Fault finding...........................................................................30 - 32
Spare parts ................................................................................... 32
SERVICING SECTION

3
INTRODUCTION
The ISOMAX F boiler is a wall mounted modulating
combination boiler with electronic ignition provid-
ing central heating and stored hot water.
The boiler is of the I2E+ category for use with Natu-
ral Gas (G20) as distributed in the United Kingdom,
or Butane (G30), Propane (G31) or Towns Gas
(G130) with the appropriate conversion kit.
The boiler has a fan assisted balanced flue which
bothdischargesthe products ofcombustionto and
draws the combustion air from the outside of the
room.
The boiler is suitable for top outlet flue connection
only but, can be fitted with horizontal flue, vertical
flue or twin-pipe flue. Refer to flue catalogue for
further details.
Both the central heating and domestic hot water
temperature are user adjustable from the boiler
control panel.
Domestic hot water demand always has priority
over heating demand.
The boiler is designed for use as part of a sealed
water central heating system with fully pumped
circulation. The pump, expansion vessel and asso-
ciated safety devices are all fitted within the boiler.
The boiler can be installed against either an exter-
nal wall or on an adjacent inside wall, that is, the
flue system will pass directly to the rear or to either
side to the terminal fitted on the outside wall face.
The installation must be carried out by a qualified
registered person in accordance with the relevant
requirements of The Building Regulations, The Wa-
ter Byelaws, The Building Standards (Scotland)
Regulations and any applicable local regulations.
These instructions should be carefully followed for
the safe and economical use of your boiler.
Ancillary equipment
A range of flue accessories are available includ-
ing vertical flues, twin-pipe flues, bends etc.
For further information contact your supplier.
Substances Hazardous to Health
The adhesives and sealants used in this appliance
are cured and give no known hazard in this state.
INSULATION PADS/CERAMIC FIBRE, GLASSYARN,
MINERAL WOOL
These can cause irritation to skin, eyes and the
respiratory tract. If you have a history of skin
complaintsyoumaybesusceptibletoirritation.High
dust levels are usual only if the material is broken.
Normal handing should not cause discomfort, but
follow normal good hygiene and wash your hands
before eating, drinking or going to the toilet.
Ifyoudosufferirritationtotheeyesorsevereirritation
to the skin, seek medical attention.
Hab 222
COMMISSIONING
Gas safety (Installation and use) Regulations
In your interests and that of gas safety, it is the law
that ALL gas appliances are installed and serviced
byaqualified registeredpersonin accordancewith
the above regulations.
Gas leak or fault
If a gas leak or fault exists or is suspected, turn the
boiler off and consult the local gas supply com-
pany or your installation/service company.
Air in the heating system
Persistent air in the heating system may indicate
leaks in the system or corrosion taking place. Call
your Installation/Servicing company.
1-On/Off button
2-Summer/Winter mode selector
3-Hot water temperature adjuster
4-Hot water set point display
5-Graphic display
6-Heating temperature adjuster
7-Heating set point display
8-Display backlight
IO
1.5 bar
158 7 26 34
mode
Diagram 1
Overheating safety
In the event of a problem, the overheating safety
devices cause safety shutdown of the boiler. If this
happens,callyour Installation/Servicing company.
Boiler controls
The control panel, located at the lower front of the
boiler casing, see diagram 1, allows the boiler to
be started, shut down, controlled and monitored
during use.
Flue
Do not obstruct the outside terminal of the boiler.

4
IO
1.5 bar
mode
Appuyer sur +ou -pour ajuster la température
maximale souhaitée du circuit chauffage
60°C
Visualisation de la température demandé
e
Appuyer sur +ou -pour ajuster la température
maximale de l'eau chaude sanitaire (38
° C à60 ° C)
Visualisation de la température demandée
50°C
Appuyer sur mode pour sélectionner la position été
1.5 bar
Appuyer sur mode pour sélectionner la position hiver
Température actuelle
dans le circuit chauffage
1.5 bar
10 °C
Apparaît lorsque le brûleur
est en fonctionnement Apparaît lorsque le brûleur fonctionne
mode
mode mode
mode
CONTROLS AND LIGHTING
To stop the boiler : Press button (1)
Adjusting the hot water temperature Adjusting the heating temperature
Lighting the boiler :
Make sure that:
The boiler is connected to the electrical supply.
The gas service cock is open.
Then follow the instructions below :
Press the On/Off button (1)
Hab 264
1
1
The pressure must be between 1 and 2 bar. If not, the system must be filled by a competent person.
Setting to the SUMMER position
(Hot water only) Setting to the WINTER position (Heating + hot water)
2
Press the mode button to select the summer symbol Press the mode button to select the winter symbol
The flame symbol appears
when the boiler is running The actual temperature
of the heating system Illuminates when
the boiler lights
Hab 261
Press + or - to adjust the maximum temperature
of the hot water (38 ° C to 60 ° C) Press + or - to adjust the maximum temperature
of the heating (38 ° C to 87 ° C)
3
To obtain domestic hot water, open a hot water tap. Hot water always has priority over central heating.
Visual indication of set temperature Visual indication of set temperature

5
SERVICING/MAINTENANCE
To ensure the continued efficient and safe opera-
tion of the boiler, it is recommended that it is
checked and serviced at regular intervals.
The frequency of servicing will depend upon the
installation conditions and usage but, in general,
once a year should be enough.
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.Ifindoubt, consult your installation/serv-
ice company.
DRAINING
Protection against freezing
If the boiler is to be out of use for any long periods
during severe weather conditions, it is recom-
mendedthatthe wholesystem,including theboiler,
be drained to avoid the risk of freezing.
If in doubt, consult your servicing company.
The
ISOMAX has a built in frost protection device
that protects the boiler from freezing. If the boiler is
to be left and there is a risk of frost, ensure that the
gas and electrical supplies are left connected. The
frost protection device will light the boiler when the
temperature of the boiler water falls below 6°C.
When the temperature reaches 16°C, the boiler
stops.
Note: This device works irrespective of any room
thermostat setting and will protect the complete
heating system.
Draining and filling
Caution: The boiler is installed as part of a sealed
system which must only be drained and filled by a
competent person.
Heating safety valve
CAUTION: A heating safety valve with a discharge
pipe is fitted to this boiler.
The valve MUST NOT BE TOUCHED except by a
qualified registered person. If the valve discharges
at any time, switch the boiler off and isolate it from
theelectricalsupply. Contact yourinstallation/serv-
ice company.
Pressure/temperature relief valve
CAUTION: A domestic hot water pressure relief
valve, with a discharge pipe is fitted to this boiler.
The valve MUST NOT BE TOUCHED except by a
qualified registered person. If the valve discharges
at any time, switch the boiler off and isolate it from
theelectricalsupply. Contact yourinstallation/serv-
ice company.
CONTROL OPTIONS
(a) Programmable room stat Part N°40010,
(b) Isocom combined boiler control &
programmable room stat part N°85915.
Diagram 2
ISOCOM

6
TECHNICAL DATA
Heating output ajustable from 10,4 kW
to 27,6 kW
from 35,484 BTU/H
to 94,170 BTU/H
Efficiency 91 %
Maximum heating temperature 87 °C
Expansion vessel effective capacity 8 l
Expansion vessel charge pressure 0,5 bar
Maximum system capacity at 75°C 180 l
Safety valve, maximum service pressure 3 bar
Products outlet diameter 60 mm
Fresh air inlet diameter 100 mm
0
10
20
30
40
50
60
120010008006004002000
12345
Pom 010 a
Flow rate through heating system (I/h)
(10 kPa = 1 m WG)
1
2
3
4
5
Bypass fully shut
Open 1/4 turn
Open 1/2 turn
Open 1 turn
Open 2 turns
Available pressure (kPa) between
heating supply and return lines
ØBurner injector 1,20 mm
Inlet pressure 20 mbar
Maxi. Burner pressure 13,8 mbar
Mini. Burner pressure 2,16 mbar
Gas rate maximum 3,20 m3/h
Gas rate minimum 1,32 m3/h
Heating
Hot water output,automatically variable from 10,4 kW
to 27,6 kW
from 35,484 BTU/H
to 94,170 BTU/H
Storage capacity 43 l
Maximum hot water temperature 60 °C
Minimum hot water temperature 37°C
Specific flow rate (for 30°C temp rise) 13,2 l/min.
Threshold flow rate 1 l/min.
Nominal water flow rate 11,3 l/min.
Temp./pressure relief valve opening pressure 7 bar
Temp./pressure relief valve opening temperature 90°C
Cylinder heat up time 7 min.
Time to reheat 70% of storage to 60°C 3 min.
Expansion valve setting 6 bar
Maximum supply pressure 8 bar
Minimum operating pressure 0,7 bar
Hot water
Electrical supply 230 V
Maximum absorbed power 235 W
Level of protection IP44
Natural Gas (G20)
ØBurner injector 0,77 mm
Inlet pressure 29 mbar
Maxi. Burner pressure 23,8 mbar
Mini. Burner pressure 3,6 mbar
Gas rate maximum 2,39 kg/h
Gas rate minimum 0,99 kg/h
Butane Gas (G30)
ØBurner injector 0,77 mm
Inlet pressure 37 mbar
Maxi. Burner pressure 30,8 mbar
Mini. Burner pressure 3,6 mbar
Gas rate maximum 2,35 kg/h
Gas rate minimum 0,97 kg/h
Propane Gas (G31)
Electrical

7
DIMENSIONS
The ISOMAX is delivered in three separate packages:
- the boiler itself
- the fixing jig
- the flue system
Hab322
Diagram 5
Weight: 71 kg
HEATING SYSTEM DESIGN
●The ISOMAX is compatible with any type of ins-
tallation.
●Heating surfaces may consist of radiators,
convectors or fan assisted convectors.
●The ISOMAX can be piped directly to an under-
floor heating system without the need for a mixing
bottle. The maximum central heating flow
temperature can be set to 53°C on the boiler
printed circuit board during commissioning.
●Pipe sectional areas shall be determined in ac-
cordance with normal practices, using the output/
pressure curve (diagram 4). The distribution system
shall be calculated in accordance with the output
requirements of the actual system, not the
maximum output of the boiler. However, provision
shall be made to ensure sufficient flow so that the
temperature difference between the flow and re-
turn pipes be less than or equal to 20°C. The mini-
mum flow is 400 l/h.
●The piping system shall be routed so as to avoid
any air pockets and facilitate permanent venting
of the installation. Bleed fittings must be provided
at every high point of the system and on all radia-
tors.
●The total volume of water permitted for the heat-
ing system depends, amongst other things, on the
static head in the cold condition. The expansion
vessel on the boiler is pressurised at 0,5 bar (corre-
sponding to a static head of 5 m w.g.) and allows
a maximum system volume of 160 litres for an aver-
age temperature of 75°C and a maximum service
pressure of 3 bar. This pressure setting can be modi-
fied at commissioning stage if the static head dif-
fers. An additional expansion vessel can be fitted
to the system if required, see diagram 8.
●Provision shall be made for a drain valve at the
lowest point of the system.
●Wherethermostatic radiatorvalvesare fitted, not
all radiators must be fitted with this type of valve,
and in particular, where the room thermostat is in-
stalled.
●In the case of an existing installation, it is ESSEN-
TIAL that the system is thoroughly flushed prior to
installing the new boiler.
Filling the system
Afillingdevice mustbefitted tothe systemtoinitially
fill the system and replace water lost during
servicing,see diagram 8.
480
600
131
890
234

8
●Copper tubing or plastic Hep20 may be used for
the domestic hot water system. Unnecessary
pressure losses should be avoided.
●A flow restrictor limiting the flow through the boiler
to a maximum of 16 l/min is fitted to the boiler.
●The boiler will operate with a minimum supply
pressure of 0,7 bar, but under reduced flow rate.
Best operating comfort will be obtained from a sup-
ply pressure of 1 bar.
DOMESTIC HOT WATER SYSTEM DESIGN
'Hard Water Areas'
In areas where the water is 'hard', more than
200mg/litre, it is recommended that a proprietary
scale reducer is fitted in the cold water supply to
the boiler.
Shy 163cUK
Diagram 6
BOILER SCHEMATIC
1-Domestic thermistor
2-Three way valve
3-Gas valve
4-Gas valve ignition module
5-Temperatur sensor for accumulation vessel
6-Accumulation vessel
7-Burner
8-Ignition electrode
9-Combustion chamber
10 - Heating safety valve (3 bar)
11 - Main heat exchanger
12 - Air pressure switch
13 - Flow detector
14 - DHW pump
15 - Non return valve
16 - Bypass
17 - Domestic heat exchanger
18 - Heating pump
19 - Heating expansion vessel
20 - Heating thermistor
21 - Overheat safety thermostat
22 - Flame sensor electrode
23 - Fan
24 - Domestic safety valve (6 bar)
25 - Loss of water sensor
26 - Domestic expansion vessel
27 - Pressure/temperature relief (7 bar)
28 - Domestic safety valve (10 bar)
A-Heating return
B-Cold water inlet
C-Heating flow
D-Domestic hot water outlet
E-Gas
D1 - Discharge from HTG safety valves
D2 - Discharge from DHW safety valves
D3 - Discharge from temp/press (to tundish)
AB C DE
D1
D1 D1 D2 D1 D3
2
3
6
426
75
8
9
1
12
13
10 28
15 14
16
18
17
19 20
22
21
23
11
25
24
27
D1 D3
Discharge from HTG+
domestic prv on jig
D2
Discharge from DHW
safety valves
Tundish
Gully
Diagram 6a
Valve
outlet size Maximum
resistance
allowed
expressed as a
length of
straight pipe
i.e. no elbows
or bends
Resistance
created by
each elbow or
bend
Minimum
size of
discharge
pipe D2
from
tundish
Minimum
size of
discharge
to tundish
G 1/2 15 mm 22mm up to 9 m 0.8 m
28 mm up to 18 m 1.0 m
35 mm up to 27 m 1.4 m
G 3/4 22 mm 28 mm up to 9 m 1.0 m
35 mm up to 18 m 1.4 m
42 mm up to 27 m 1.7 m
G 1 28 mm 35 mm up to 9 m 1.4 m
42 mm up to 18 m 1.7 m
54 mm up to 27 m 2.3 m

9
FIXING JIG
C- Heating flow fitting with isolating valve (q),
drain knob (r) and safety valve (10).
D- Domestic hot water outlet fitting with safety
valve (28).
E- Gas fitting.
The fixing jig is made up, from left to right, as fol-
lows:
A- Heatingreturnfittingwith isolatingvalve(v) and
drain knob (u).
B- Cold water inlet fitting with isolating valve
(m)and factory fitted flow regulator and filter (not
shown).
Diagram 7
Pla 213
➜
u
➜
m
v
qr
10
28
AB C D E
PIPING SYSTEM INSTALLATION
●Heating system connections - Pipe diam. 22mm
●Hot water system connections - Pipe diam. 15mm
●Gas connection - Pipe diam. 22mm
●Domestic safety valve connection - Pipe
diam.15mm
●Heating safety valve connection - Pipe diam.
15mm
Water connection
Connect the copper connections supplied, to the
fixing jig fittings, see diagram 7. Connect the sys-
Sch 173a
Diagram 8
tem pipework to the boiler observing the correct
flow and return format as shown in diagram 8.
There are two sets of two safety valves fitted to this
appliance. Two are located on the jig diagram 7,
(10) heating safety valve 3 bar, and (28) DHW
safetyvalve10 bar. Theothertwo arelocatedinside
the boiler (diagram 6,) (27) pressure/temperature
relief safety valve 7 bar/90°C, and (24) DHW safety
valve 6 bar.
Flow
control valve Drain point
Filling device
Bypass
valve
Domestic
water
Heating
circuit
Return
Additional
expansion
vessel
(if required)
Boiler
Pressure
reducing
valve
(supplied)
Thermostatic
mixing valve
Thermostaticaly
controlled
hot water
Boiler
"set temperature"
hot water
Temperature
adjustment
Hot
Cold supply
MIX
HC

10
PIPING SYSTEM INSTALLATION
Step. 1
Theinternalsafetyvalves havebeentee'd together
and the discharge pipe run so that it exits at the
right hand bottom of the boiler (diagram 6) (D2).
The tundish (supplied) must be used with this outlet
within the normal guidelines and code of practice
(diagram 6a).
Step 2
Tee the domestic safety valve (diagram 7) (28)
outlet to the heating safety valve (10) outlet
together. You can either extend this pipe
horizontally to the outside wall. WARNING, It must
not discharge above an entrance or window or
anytypeof public accessarea,the discharge must
be extend using no less than 15 mm o.d. pipe to
discharge in a visible position outside the building,
facing downard preferably over a drain. The pipe
must have a continuous fall and be routed to a
position so that any discharge of water, possibly
steam, cannot create any danger to persons,
damage to property or external electrical
components and wiring.
alternatively : The dischargepipecan be tee'dinto
theotherdischarge pipeafterthe tundish(diagram
6) provided that it has a continuous fall and that
provisions are made for the size of discharge pipe
immediately after the tundish (see diagram 6a) .
Safety valve discharge
Domestic hot water supply options
Under normal circumstances, the domestic hot
water storage temperature inside the boiler can
be stored between 37 and 60°C. It is
recommendedthatthe boilerstoragetemperature
is set by the user to the maximum of 60°C - this will
ensure a more plentiful supply of hot water.
It may be desirable to provide hot water to
separate outlets at different temperatures (for
example, to provide a limited temperature to
prevent the risk of scalding). To be able to do this,
a thermostatic mixing valve is supplied with the
Isomaxboiler(factory setto43°C)andcan befitted
during the installation procedure.
There are 2 options for the domestic hot water
supply :
1 - Piping the hot water supply without the use of
the mixing valve to provide hot water to all taps at
the same temperature.
2 - Piping the hot water supply using the mixing
valve (supplied) to provide hot water at boiler hot
water “set temperature”to one tap and
thermostatically controlled hot water to another
tap(s).
To pipe thehotwater supply usingthemixingvalve,
refer to diagram 8. This shows one outlet supplying
hot water at the boiler hot water "set temperature"
and one hot water outlet at a temperature pre-set
at the mixing valve. The mixing valve can be set
between 35 and 60°C. It is recommended that the
valve is adjusted (and locked) by the installer to
the desired temperature.
The connections to the mixing valve are :
H - Hot water supply from boiler
C - Reduced cold water supply
MIX - Thermostatically controlled outlet
Warning : It is strongly recommended that the cold
water supply to the mixing valve is taken from the
reduced side of the pressure reducing valve
(supplied)
Note 1 : The mixing valve is fitted with two in-line
strainer, one on the hot inlet and one on the cold
inlet. For servicing details of these, refer to the
separateinstructionssupplied withthemixing valve.
Note 2 : The mixing valve incorporates a "rapid
failsafe" device which will automatically close the
valve to safety in the event of supply failure on
either hot or cold water.
Thedischargemust be extendedusingnot lessthan
22 m o.d. pipe, to discharge in a visible position
outside the building, facing downward preferably
over a drain.
Thepipemust have acontinuousfall andberouted
to a position so that any discharge of water, possi-
bly boiling or steam, cannot create any danger to
persons, damage to property or external electri-
cal components and wiring. Tighten all pipe con-
nection joints.
Gas connection
●The supply from the governed gas meter must be
of adequate size to provide a constant inlet work-
ing pressure of 20 mbar (8 in w.g.).
To avoid low gas pressure problems, it is recom-
mended that the gas supply is connected using 22
mm pipe.
●On completion, the gas installation must be
testedusingthepressure dropmethod and purged
in accordance with the current issue of BS6891.
Gas Safety (Installation and use) Regulations
In your interests and that of gas safety, it is the law
that ALL gas appliances are installed and serviced
byaqualified registeredperson inaccordancewith
the above regulations.

11
20 mm
mini
600
120
169
Ø105 pour sortie ventouse (type F)
==
900
2,10 m au sol (pour les modèles type C)
20
65
234
Ins 090a
Clearances
The position of the boiler must be such that there is
adequate space for servicing.
The recommended clearances are:
20 mm either side of the boiler.
600 mm at the front of the boiler.
300 mm below the boiler.
●Place template on wall in required position, mak-
ing allowances for the necessary clearances etc.
Note: It is permissible to install the boiler with smaller
clearances than those quoted above PROVIDING
that adequate consideration is given for Servicing/
Repairs at a later date. If any doubt exists, contact
the Saunier Duval Technical Helpline 01773 828400.
●Mark the position of the holes for the hanging
bracket and jig.
●Drill, plug and fix the hanging bracket to the wall
using suitable screws.
●Check that the hanging bracket is level.
●Drill plug and fix the fixing jig to the wall.
●For horizontal flue system, mark the position for
the flue hole as follows:
Flue to rear of boiler
●Mark correct position of hole from template.
Flue to side of boiler
●Mark the horizontal centre line for the hole on the
rear wall. Extend the horizontal centre line to the
side wall and mark the vertical centre line of flue
hole as shown in diagram 9.
Cutting the flue hole
●Making allowance for the slope of the flue, cut
hole in external wall, preferably using a core drill.
For installations with internal and external access
use a 10 5 mm diameter core drill.
For installations with internal access only use a 125
mm diameter core drill.
Important
When cutting the flue hole and when extending
the flue centre line to a side wall, remember that
the flue system must have a fall of about 35 mm
BOILER LOCATION
Diagram 9
per metre of flue DOWNWARD towards the termi-
nal. There must NEVER be a downward incline to-
wards the boiler.
Terminal position
The minimum acceptable spacings from the ter-
minal to obstructions and ventilation openings are
shown in diagram 10.
The boiler must be installed so that the terminal is
exposed to the external air.
Should any doubt exist as to the permissible posi-
tion of the terminal, contact the Saunier Duval
Technical Helpline 01773 828400.
Terminal guard
Ifaterminal guardisrequired,asuitableguard can
be obtained from your supplier, Saunier Duval part
number 85373.
Cupboard or compartment ventilation
The boiler can be fitted in a cupboard or compart-
ment without the need for permanent ventilation.
Minimum dimensions (in mm) for the positioning of flue terminals
A-Under a window .................................................... 300
B-Under an air vent .................................................. 300
C-Under a gutter ......................................................... 75
D-Under a balcony ................................................... 300
E-From an adjacent window .................................. 300
F-From an adjacent air vent ................................... 300
G-From vertical or horizontal air pipes.................... 300
H-From an external corner of the building............ 300
I-From an internal corner of the building ............. 300
L-From the ground or from another floor .............. 300
M-Between two terminals vertically...................... 1500
N-Between two terminals horizontally.................... 600
Ven 060b
NC
D
M
A
B
EF
G
IH
L
Diagram 10
Ø105 or 125 core drill

12
ee a
a
X
X
BOILER INSTALLATION
Statutory requirements
The installation of this boiler must be carried out by
a qualified registered person in accordance with
the relevant requirements of the current issue of:
The Gas Safety (Installation and Use) Regulations
The Building Regulations
The local water company Byelaws
The Building Standards Regulations (Scotland)
The Health and Safety at Work Act
Sheet metal parts
WARNING. When installing or servicing this boiler,
care should be taken when handling the edges of
sheetmetalparts to avoidthepossibility ofpersonal
injury.
Installing the boiler
Priortostarting work, thesystemmust be thoroughly
flushed using a propriety cleanser such as Sentinel
X300 to eliminate any foreign matter and contami-
nation e.g. metal filings, solder particles, oil, grease
etc.
Note.Solventproducts couldcausedamage tothe
system.
●Engage boiler upper part onto the hanging
bracket.
●Fit the washers between the boiler pipes and the
inlet and outlet fittings on the fixing jig and con-
nect the various couplings between the boiler and
jig.
FLUE INSTALLATION
Top outlet flue - kit 85090
The boiler is only suitable for top outlet flue
connection.
Rear flue systems
The calculate the lenght when flueing to the rear
measure e (diagram 11) plus 25 mm outer flue pipe
and eplus 125 mm to inner pipe measurement.
Calculation of cutting lengths when flueing to the
right or left
●Measure wall thickness e (mm), see diagram 11.
For right hand applications
●Measure distance from inside face of wall to side
of the boiler a (diagram 11) add 350 mm to outer
pipe measurement and 445 mm to inner pipe
mesurement.
For left hand applications
●Measure distance from inside face of wall to side
of the boiler a (diagram 11) subtract 25 mm for
outer pipe length and add 75 mm to inner pipe
length measurement.
●Refer to table 2 for cutting lengths of both inner
and outer flue pipes for each of the various flue
options available.
Important: All flue cutting lengths must be meas-
ured from the terminal end of the flue pipes, see
diagram 12.
When the dimension X measured on site is greater
thanthatgiven intable 2.Extensions willberequired
as necessary.
Important: All cutting lengths should be measured
from the push fit joint end of the extension pipe.
Do not leave any burrs or sharp edges on the cut
ends of the pipes.
Note : maximum horizontal flue lenght without
bends is 3 m.
Table 2
Flue cutting lengths (mm)
Rear flue
Outer pipe : e + 25, inner pipe : e + 120
Comment : maximum distance 'x' without extension 770 mm
Right side flue
Outer pipe : e + a + 350, inner pipe : e + a + 450
Comment : maximum distance 'x' without extension 515 mm
Left side flue
Outer pipe : e - 25, inner pipe : e + 125
Comment : maximum distance 'x' without extension 1087 mm
Hab 210a
Diagram 11
Ven 089
Diagram 12
Cutting length
Outer pipe
Inner pipe
Cutting length

13
FLUE INSTALLATION
Installation of flue assembly
●Fit rubber sealing collar (F), see diagram 13, into
groove at the outer end of pipe (A).
●Fit outer pipe (A) into wall with groove to the out-
side.
●Pull pipe inwards to bring rubber sealing collar
hard up against external wall, see diagram 14.
●Fit internal plastic flange (G) ontoouter pipe.Push
along the pipe until engaged against internal wall.
●From inside, insert inner pipe (B) into outer pipe.
●Fit both ‘O’rings (J) into the flue elbow (C), one
at the inlet, one at the outlet. By necessity, they
are a loose fit, apply a small amount of silicone
grease to each ‘O’ring when fitting.
●Wrap sleeve (D) over outer pipe (A) and elbow
(C) ensuring it is the correct way round.
●Take hold of the inner flue and push gently onto
the elbow outlet taking care not to tear the ‘O’
ring.
●Open fixing collard (D) and locate between
elbow and outer pipe (A). Close fixing jig.
●Engage the two fixing clips (E) onto the colar
onto (D) and press down to lock into position.
Secure clips with screws provided.
Important:Ifthe fluehasbeen cut,ensurethat there
are no burrs that could damage the ‘O’ring.
●For flue systems less than 1,5 m long, leave the
restrictor (a) fitted in the fan outlet, see diagram
15.
●Remove the backing from the self adhesive gas-
ket (H) and carefully fit gasket to base of flue el-
bow.
●Fit elbow onto boiler and secure with the four
screws (I).
Concentric flue system
The maximum permissible length (L) for the concentric flue system is 3 m. For flue systems up to 1,5 m
length, the restrictor (a) supplied fitted to the boiler, inside the fan outlet, must be left in place. For longer
flue systems, the restrictor must be removed.
For each 90°flue elbow used, (or two 45°elbows) the maximum permissible length (L) must be reduced
by 1 metre.
Pho 087
Diagram 14
Hab 249a
Diagram 15
234
65
L
a
Gasket
Pho 451
B
C
J
I
H
FG
A
D
The flue kit 86285 is 1000 mm long and comprises:
- Outer pipe .............................................................. A
- Inner pipe ................................................................B
- Flue elbow ..............................................................C
- Fixing collar............................................................. D
- Locking clips............................................................E
- External rubber sealing collar............................... F
- Internal flange .......................................................G
- Gasket..................................................................... H
- Screws .......................................................................I
- 'O' rings.....................................................................J
Diagram 13
E

14
Ins 060
Diagram 16
The boiler is supplied with a mains lead at-
tached. Connect this to the electrical supply.
Sch 171
E
Sch 172
¡C
E E
Without room
thermostat
With voltage free room
thermostat
Diagram 17
ELECTRICAL CONNECTION
Warning. This boiler must be earthed
All system components must be of an approved
type.
Connectionofthewhole electrical systemandany
heatingsystemcontrolstothe electricalsupplymust
be through a common isolator.
Isolation should preferably be by a double pole
switched fused spur box having a minimum con-
tact separation of 3 mm on each pole. The fused
spur box should be readily accessible and prefer-
ably adjacent to the boiler. It should be identified
as to its use.
A fused three pin plug and shuttered socket outlet
may be used instead of a fused spur box provided
that:
a) They are not used in a room containing a fixed
bath or shower.
b) Both the plug and socket comply with the cur-
rent issue of BS1363.
The mains electrical supply must be maintained at
all times in order to provide domestic hot water.
Donotinterruptthe mains supply withatime switch
or programmer.
WARNING: ON NO ACCOUNT MUST ANY EXTERNAL
VOLTAGE BE APPLIED TO ANY OF THE TERMINALS ON
THE HEATING CONTROLS CONNECTION PLUG.
Warning: This appliance must be wired in accord-
ance with these instructions. Any fault arising from
incorrectwiringcannot beputright undertheterms
of the Saunier Duval guarantee.
External controls
The ISOMAX boiler is designed to operate at maxi-
mum efficiency at all times, but will be most effi-
cient and economical when connected to a room
thermostat.
A suitable room thermostat is available as an ac-
cessory, Saunier Duval part number 40011. Please
contact your supplier.
Also available :
For extra control or if the boiler is to be sited in a
garage or utility room an optional remote control
unitwithprogrammable roomstatcanbe obtained
part number 85915 (Isocom), diagram 2. This is a
dual function unit (a) boiler control (same as boiler
facia) (b) programmable room stat. Full fitting
instructions supplied with the unit.
The boiler will work for heating without a room ther-
mostat being connected provided that the wire
link fitted between the two terminals of the con-
nector (E) is left in place, see diagram 17.
Alternatively, a 230Vroomthermostatcanbeused
but do not make any connection to the compen-
sating resistor, see diagram 17.
ON NO ACCOUNT must any electrical voltage be
applied to any of the terminals of the external con-
trols plug.
Note: For further information, see the building
regulations 1991 - Conservation of Fuel and Power
- 1995 edition - appendix G, Table 4b.
Isocom only
Leave link in place for no external controls.
IMPORTANT
F
F

15
3
Undo cap
on auto-
matic air
vent on
top of
pump and
leave un-
done.
Open the boiler isolating valves (v
and q), the slot of the screw corre-
sponds to flow direction.
Fully open valve mby turning anti-
clockwise.
COMMISSIONING
Reg 018
Diagram 18
The commissioning and first firing of the boiler must
only be done by a qualifed registered person.
Gas installation
It is recommended that any air is purged from the
supply at the gas inlet test point on the gas valve,
see diagram 18.
Filling the system
4
IO
0.0 bar
1
L'afficheur indique 0 bar de pression et clignote
Le témoin lumineux clignote
mode
Hab 260
1Press the mains 'On/Off' button
1.5 bar
mo
d
The pressure must be between 1 and 2 bar
Hab 265
Open filling device fitted previously, fill the system
untilthepressureindicated on thedisplayis between
1 and 2 bar. Close filling device.
Reg 008
The warning light will illuminate The display will indicate 0 bar pressure in the system
Pla 213
➜
v
➜
mq
2

16
COMMISSIONING
Make sure the display indicates a system pressure of between 1 and 2 bar. Re-fill system as
necessary.
IO
1.5 bar
mode
Hab 265
8
5 76
➜
➜
Bleed each radiator to re-
move the air, re-tighten
bleed screws.
Open various hot
water taps to bleed
system.
Leave the cap on the
pump auto air vent open.
Reg 008
Ins 061
Ins 062
The pressure must be between 1 and 2 bar

17
IO
1.5 bar
mode
COMMISSIONING
To stop the boiler : Press button (1)
Make sure that:
The boiler is connected to the electrical supply.
The gas service cock is open.
Then follow the instructions below :
Press the On/Off button (1)
Hab 264
1
The pressure must be between 1 and 2 bar. If not, the system must be filled by a competent person.
Appuyer sur +ou -pour ajuster la température
maximale souhaitée du circuit chauffage
60
°C
Visualisation de la température demandé
e
Appuyer sur mode pour sélectionner la position hiver
Température actuelle
dans le circuit chauffage
1.5 bar
10
°C
Apparaît lorsque le
brûleur fonctionne
mode
mode
Adjusting the heating temperature
Setting to the WINTER position
(Heating + hot water)
The actual temperature
of the heating system Illuminates when
the boiler lights
Hab 261
Press + or - to adjust the maximum temperature
of the heating (38 ° C to 87 ° C)
Visual indication of set temperature
Lighting the boiler :
Press the mode button to select the winter symbol
1
3
2
●Adjust heating temperature to maximum .
●Check that any external controls, if fitted, are
calling for heat (set room thermostat to maximum).
●Allow the temperature to rise to the maximum
value, with all radiator valves open. The tempera-
ture rise will cause release of the gases contained
in the water of the central heating system.
●Gases driven towards the boiler will be automati-
cally released through the automatic air vent.
●The gases trapped at the highest point of the sys-
tem must be released by bleeding the radiators.
On reaching maximum temperature, the boiler
should be turned off and the system drained as
rapidly as possible whilst still hot.
●Refill system to a pressure of between 1 and 2
bar and vent as before.
●Restart boiler and operate until a maximum tem-
perature is reached. Shut down boiler and vent
heating system. If necessary, top up heating sys-
tem and make sure that a pressure of at least 1 bar
is indicated when system is COLD.

18
COMMISSIONING
Setting the heating output
The heating output can be set without the use of a
pressure gauge; proceed as follows:
●Press the display light button
and keep pressed for 5 seconds, see diagram 20.
Note:The boiler has now been put into 'Service
Mode', allowing certain adjustments to be made
and diagnostic fault codes to be displayed. Refer
to the 'Servicing Instructions' for further details.
The heating output, in kW, is shown on the left hand
side of the display, see diagram 21.
●Remove the blanking plug from the front of the
control panel to gain access to the heating ad-
justing screw.
●Adjust the heating output by turning the screw
clockwise to increase, anti-clockwise to decrease.
●Refit blanking plug.
Note: Adjustment of the heating output does not
affect the domestic hot water output.
For kW to Btu/hr conversion refer to table 5.
Setting the heating output
20 01
5 s
1
2
mode
Reg 051/UK
Setting the heating output
Reg 052
Adjustment screw
Theheatingoutput,in kW,
is shown on the display.
Diagram 21
Diagram 22
Diagram 20
Table 5
kW to Btu/hr conversion
kW Btu/hr
10 34,120
12 40,940
14 47,770
16 54,590
18 61,420
kW Btu/hr
20 68,240
22 75,060
24 81,890
26 88,710
28 95,540
Setting the maximum heating temperature
The maximum heating temperature can be preset
at commissioning stage to suit the type of heating
system.
For example, for use with underfloor heating, the
maximumheatingtemperature can besetto 53°C.
To adjust the maximum temperature, proceed as
follows:
Remove the blanking plug (b) from the rear of
the control panel to gain acess to selector switch
SW1 (see diagram 22).
Adjust toggles 1and 2 to give the desired maxi-
mum heating temperature, see diagram
Note: To adjust the maximum heating temperature
it is only necessary to change toggles 1 and 2. Do
NOT touch any other toggles.
Refit blanking plug.
b
➦
Reg 053
SAFETY DEVICES
The ISOMAX incorporates a visual display that indi-
cates fault conditions, should they occur.
In the event of a fault, the display will indicate, by
means of pictograms and/or letters and numbers,
exactly in which area the fault lies.
Should the boiler fail to operate during Commis-
sioning, the most likely fault is that the gas supply
to the boiler has not been turned on or purged suf-
ficiently or that there is no pressure in the heating
system. These are indicated as follows :
1234567
O
N
SW1
1=ON, 2=ON ➜53°C. Maximum.
1=OFF, 2=OFF ➜73°C. Maximum.
1=OFF, 2=ON ➜87°C. Maximum.
Factory setting ➜ 73°C.
kW Btu/hr
30 102,360
32 109,180
34 116,000
35 119,420

19
SAFETY DEVICES
No gas supply This will be indicated
on the display as a
pictogramofa spark.
To rectify this, pro-
ceed as follows:
Switch off the boiler at the On/
Off push button.
Rectify the gas supply problem.
Restart the boiler by pressing the
On/Off button.
--------------------------
Insufficient system pressure This will be indicated
on the display as a
flashing warning indi-
cating the system
pressure is low.
To rectify this the system must be re-filled, refer to
'Commissioning'.
--------------------------
Other faults
These are indicated on the display by a fault code
andatelephone symbol.Furtherinformation onthe
fault codes can be found in the 'Servicing Instruc-
tions'.
General safety devices
Air flow rate safety device
If an obstruction, even partial, of the flue occurs,
for any reason whatsoever, the built in safety sys-
tem of the boiler will turn the boiler OFF and the
fan will continue to run.
The boiler will be ready to operate when the fault
has been cleared.
Overheat safety
In case of boiler overheating, the overheat ther-
mostat will turn the boiler off. The thermostat, lo-
cated on the heat exchanger flow pipe, will need
to be manually reset.
In case of power supply failure
The boiler no longer operates.
As soon as power supply is restored, the boiler will
be automatically restarted.
Frost protection
The ISOMAX has a built in frost protection device
that protects the boiler from freezing. If the boiler is
to be left and there is a risk of frost, ensure that the
gas and electrical supplies are left connected. The
frost protection device will light the boiler when the
temperature of the boiler water falls below 6°C.
When the temperature reaches 16°C, the boiler
stops.
Note : This device works irrespective of any room
thermostat setting and will protect the complete
heating system.
➜
IO
1
0.3 bar
Should it become necessary to change the gas
type, a modification kit will be required.
This modification must only be carried out by a
suitably qualified engineer.
Conversion natural Gas (G20) to G30/G31 Part No.
86216.
CHANGING GAS TYPE

20
SETTINGS
Gas valve setting
All boilers are tested and factory set during manu-
facture.Shouldit be necessarytoreset a gasvalve,
for example, after replacement, proceed as fol-
lows:
Shut down boiler.
Minimum setting
Remove one electrical connector from the
modulating gas valve coil, see diagram 23.
Connect a suitable pressure gauge.
Set the OFF/Summer/Winter switch to the ‘Sum-
mer’position.
Adjust the domestic hot water temperature ad-
juster to maximum setting.
Remove the protective cover from the gas valve
adjuster.
Turn nut ‘A’, see diagram 23:
CLOCKWISE: To increase the pressure.
ANTICLOCKWISE: To decrease the pressure.
Maximum setting
Reconnect the electrical connector removed
from the modulating gas valve coil.
Remove the protective cover from the gas valve
adjuster.
Turn nut ‘B’, see diagram 23:
CLOCKWISE: To increase the pressure.
ANTICLOCKWISE: To decrease the pressure.
After adjustment, refit the cover to the gas valve
adjuster.
Bypass
The ISOMAX has a built-in bypass. This must be ad-
justedaccordingto the requirementsof thesystem,
refer to the flow rate pressure curve (diagram 4).
The boiler is supplied with the built-in bypass open
a half a turn. It is adjusted by turning the bypass
screw (a), see diagram 24. Turn the screw clock-
wise 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, see diagram 8.
Any bypass must be fitted before system controls.
MODULATING COIL
Diagram 23
Reg 020
a
Diagram 24
Reg 054
Electrical
connection