Atag IS 12 Release note

8G.51.82.04 / 09.16 Changes reserved. E.& O. E.
Installation & Servicing
Instructions
These instructions are to be retained by the user.
Natural Gas Boilers
Boiler G.C No
iS 12 41-310-18
iS 15 41-310-20
iS 18 41-310-22
iS 24 41-310-24
iS 32 41-310-26
iS 40 41-310-28
Propane Gas Boilers
Boiler G.C No
iS 12 LPG 41-310-19
iS 15 LPG 41-310-21
iS 18 LPG 41-310-23
iS 24 LPG 41-310-25
iS 32 LPG 41-310-27
iS 40 LPG 41-310-29
CE PIN 0063CQ3634
iS 12
iS 15
iS 18
iS 24
iS 32
iS 40

Installation & Servicing instructions ATAG iS-Range
2
%
bar
°C
+
--
+
reset
eco (OK)
(ESC)
ECO
Explanation of the Control Panel & Buttons
DHW Visible when DHW program is active
Flashing when there is a heat demand for DHW
Error Error indication (accompanied with a code).
Alert Service-mode or blocking
Pump Visible when pump is set to continuously
Flashing when frost program is active
Flame Visible when boiler is active for heating or DHW
Heating Visible when heating program is active
Flashing when there is a heat demand for heating
Central heating program (On = +, O󰀨 = -)
Setting of boiler temperature (max. ow temperature)
+/-function (ancillary function: OK and Escape)
Press 6 seconds for Information
Reset button
DHW button
+/-function (ancillary function: Scroll and +/-function)
Commissioning function (Press both + buttons for 6 seconds)
Pump function (Press both - buttons for 6 seconds)
Information on the water pressure:
The default view of the display shows OK. Press the eco-button for
6 seconds and press the scroll-buttons until A6 is displayed.
The actual water pressure will be shown:
Water pressure too low
Code 118 and spanner symbol visible:
Water pressure is too low (<0.8 bar).
Power is reduced by 20%. The installation should be relled.
or
Code 118 and spanner symbol visible:
Water pressure is too low (<0.5 bar).
The boiler is taken out of operation. The installation should be relled.
After the installation has been relled and if the pressure was below
0.5 bar the de-aeration program will start (Code 105 and spanner
symbol visible). This will last for approx 7 mins.
Water pressure too high
Code 117 and spanner symbol visible:
Water pressure is too high (> 3.0 bar).
The boiler is taken out of operation.
The installation pressure should be reduced by draining water from the heating system.
See chapter 12 for more information about button functions and read-out.
-
+
eco
reset
+
--
+
+
-

Installation & Servicing instructions ATAG iS-Range
3
Work on the installation should only be carried out by qualied personnel with calibrated equipment
and appropriate tools.
Contents
1 Introduction ....................................................................................................................................4
2 Rules & Regulations (Symbols) .....................................................................................................5
3 Technical specications..................................................................................................................7
4 Dimensions ...................................................................................................................................8
5 Delivery package............................................................................................................................9
6 Boiler description............................................................................................................................9
7 Boiler photo components list ........................................................................................................10
8 Mounting boiler frame .................................................................................................................. 11
8.1 Wall frame .........................................................................................................................12
9 Connecting boiler .........................................................................................................................13
9.1 Central heating system .....................................................................................................13
9.2 Expansion vessel ..............................................................................................................14
9.3 Water quality .....................................................................................................................14
9.4 Heating systems with plastic pipes ...................................................................................16
9.5 Gas connection in general ................................................................................................16
9.5.1 Natural gas connection (NG) ............................................................................................16
9.5.2 Propane gas connection (LPG).........................................................................................16
9.6 External DHW cylinder......................................................................................................18
9.7 Condensation drain pipe ...................................................................................................21
9.8 Flue gas exhaust system ..................................................................................................25
9.8.1 Flue terminal locations ......................................................................................................26
9.8.2 Dimensioning of the ue gas and air intake duct ............................................................29
9.9 Fitting the boiler onto the boiler frame .............................................................................31
10 Electrical connection ....................................................................................................................33
10.1 One controller & connections............................................................................................34
10.2 Weather compensation & connections .............................................................................34
10.3 Electrical diagram .............................................................................................................35
11 Filling system ...............................................................................................................................36
12 Boiler controls ..............................................................................................................................37
12.1 Controls and explanation of the functions.........................................................................38
13 Commissioning the boiler.............................................................................................................39
13.1 Settings .............................................................................................................................41
13.2 Parameter chapter ............................................................................................................41
14 Isolating the boiler ........................................................................................................................42
15 Commissioning.............................................................................................................................43
15.1 Checking the CO2.............................................................................................................44
15.2 Checking ue integrity.......................................................................................................47
15.3 CO and combustion checks .............................................................................................48
16 Routine servicing..........................................................................................................................50
16.1 Component replacement...................................................................................................53
16.2 User's instructions.............................................................................................................54
16.3 Warranty............................................................................................................................54
17 Error codes and fault nding .......................................................................................................55
Annex A System water additives .....................................................................................................56
Annex B Declaration of conformity ..................................................................................................57
Annex C Short parts list ...................................................................................................................58

Installation & Servicing instructions ATAG iS-Range
4
1 Introduction
These instructions describe the functioning, installation, use and primary maintenance of ATAG central heating
boilers for the United Kingdom.
These instructions are intended for the use of Gas Safe registed installers in connection with the installation
and putting into operation of ATAG boilers. It is advisable to read these instructions thoroughly, well in
advance of installation. Separate instructions for use are supplied with the boiler for users of ATAG central
heating boilers. ATAG is not liable for the consequences of mistakes or shortcomings which have found their
way into the installation instructions or user’s manual. Further, ATAG reserves the right to alter its products
without prior notication.
When delivering the boiler, give the customer clear instructions concerning its use; present the
customer with the user’s manual and warranty card.
Each boiler is tted with an identication plate. Consult the details on this plate to verify whether the boiler is
compliant with its intended location, e.g.: gas type, power source and exhaust classication.
On completion of the installation the installer or commissioning engineer must ll out and complete the
Benchmark Commissioning Checklist found on page 62 of this manual and hand this to the customer
for future record keeping. The Benchmark Service Record must also be completed by the service agent
following each service call, and return to the customer.

Installation & Servicing instructions ATAG iS-Range
5
2 Rules & Regulations (Symbols)
The following regulations apply to installation of ATAG central heating boilers:
Legislation and Regulations.
Gas Safety (Installation and Use). All gas appliances must by law, be installed by a competent person, eg.
Members of Gas Safe Register and in accordance with the current Gas Safety Regulation. Failure to install
appliance correctly could lead to prosecution.
All Gas Safe registered installers carry a Gas Safe ID card and have a registration number. You can call Gas
Safe Register directly on 0800 408 5577.
In addition to the above regulations this appliance must be installed in compliance with the current IEE
Regulations, the Building Standards (Scotland Consolidation) Regulations. Regulations and bye laws of the
Local Water Authority and the Current Health and Safety Regulation.
The Benchmark Scheme
Benchmark places responsibilities on both manufacturers and installers. The
purpose is to ensure that customers are provided with the correct equipment
for their needs, that it is installed, commissioned and serviced in accordance
with the manufacturer’s instructions by competent persons and that it meets the
requirements of the appropriate Building Regulations. The Benchmark Checklist can be used to demonstrate
compliance with Building Regulations and should be provided to the customer for future reference.
Installers are required to carry out installation, commissioning and servicing work in accordance with the
Benchmark Code of Practice which is available from the Heating and Hotwater Industry Council who manage
and promote the Scheme.
Visit www.centralheating.co.uk for more information.
The current Electricity at Work Regulation must be complied with and also be in accordance with the relevant
and current editions of the British Standards.
The ATAG iS boiler is a certied appliance and must not be modied or installed in any way contrary to
this Installation Manual. Manufacturers instructions must not be taken, in any way, as overriding statutory
obligations.
The ATAG iS boiler is a central heating boiler with an integrated hot water function. The boiler must be
connected according to these instructions and all installation norms in respect of the part of the boiler to be
connected.
The appliance is not to be used by children or persons with reduced physical, sensory or mental
capabilities, or lack of experience and knowledge, unless they have been given supervision or
instruction.
Children being supervised not to play with the appliance.
Observe the following rules of safety:
- All work on the boiler must take place in a dry environment.
- ATAG boilers may never be in operation without their housing, except in connection with maintenance or
adjustments (see Chapter 15 and 16).
- Never allow electrical or electronic components to come into contact with water.
Carry out the following tasks in connection with maintenance, etc. to an already-installed boiler:
- Shut down all programs
- Close the gas isolation valve
- Shut down the 230V power supply
See chapter 15 and 16 for further instructions.

Installation & Servicing instructions ATAG iS-Range
6
Take note of the following when maintenance or adjustments are needed:
- The boiler must be able to function during these activities; for this reason, the boiler’s 230V power supply,
gas pressure and water pressure must be maintained. Ensure that there is not a source of potential
danger during these activities.
Following maintenance or other activities; always check the installation of all parts through which
gas ows (using leak detection spray).
The following (safety) symbols may be encountered in these installation instructions and on the boiler
(packaging):
Boiler must be stored away from frost.
Protect packaging and/or contents from damage as a result of insu󰀩cient care taken during
transport.
Protect the boiler from weather conditions during transport and storage whilst still in its packaging.
If and how to clamp when using transport trucks with clamp equipment.
If and how to transport when using a rolling jack.
The whole packaging is made of recycled materials and can be recycled again.
Transport and place the boiler in its packaging in this position.
Do not to step on or stand on the package.
An assembly or dismantling must be carried out.
Pay extra attention in connection with a particular operation.
Useful tip or advice

Installation & Servicing instructions ATAG iS-Range
7
3 Technical specications
Boiler type iS 12 iS 15 iS 18 iS 24 iS 32 iS 40
Type heat exchanger iCon1 iCon1 iCon1 iCon1 iCon2 iCon2
Input CH Net kW 10.8 13.5 16.2 21.6 28.8 36.0
Qn Input CH Gross kW 12.0 15.0 18.0 24.0 32.0 40.0
Modulation range CH (capacity 50/30°C) kW 5.0 - 11.8 5.0 - 14.7 5.0 - 17.5 5.0 - 23.2 6.9 - 31.2 6.9 - 38.8
Nox class EN15502-1
O2 (at full load) %
CO2 (at full load) %
Temperature class flue
Appliance type
Flue gas temp. CH (80/60°C on full load) °C
Flue gas temp. CH (50/30°C on low load) °C
Categories
Gas consumption m3/hr 1.14 1.43 1.72 2.29 3.05 3.81
Electr. power consumption max. W 62 68 77 96 74 99
Electr. power consumption part load W 47 51 58 72 56 74
Electr. power consumption stand by W
Current V/Hz
Degree of protection acc. EN 60529
Weight boiler + jig (empty) kg 39 39 39 39 42 42
Width mm 440 440 440 440 440 440
Height (excl. flue) mm 700 700 700 700 700 700
Depth mm 355 355 355 355 355 355
Overrun time pump CH sec
Content expansion vessel l 8 8
8888
Pre-charge pressure exp. Vessel bar 1 1
1111
PMS Water pressure CH min./max. bar
Flow temperature max. °C
Pump type
Available pump height CH kPa 25 25 25 25 20 20
SAP Annual Efficiency NG % 89.8 89.8 89.8 89.8 89.8 89.8
CE product identification number(PIN)
Technical specifications Propane gas
Boiler type iS 12 iS 15 iS 18 iS 24 iS 32 iS 40
Heat exchanger type iCon1 iCon1 iCon1 iCon2 iCon2 iCon2
O2 (at full load) %
CO2 (at full load) %
Pre pressure mbar
Input CH Net kW 10.8 13.5 16.2 21.6 28.8 36.0
Gas consumption m3/hr 0.45 0.56 0.68 0.90 1.20 1.50
Output (80/60°C) kW 10.7 13.3 15.9 21.2 28.4 35.4
Output (50/30°C) kW 11.8 14.7 17.5 23.2 31.2 38.8
Weight boiler + jig (empty) kg 39 39 39 42 42 42
ErP specifications according to European Guideline 2010/30/EU
Boiler type iS 12 iS 15 iS 18 iS 24 iS 32 iS 40
Seasonal space heating energy efficiency class A A
AAAA
Pn Power outpu
t
kW 11 13 16 21 28 35
QHE Annual energy consumption GJ 35 43 52 69 92 115
ηs Seasonal space heating energy efficiency %93 93 93 94 94 94
LWA Sound power level, indoors dB 37 37 43 46 48 54
4.7
9.0
System
5
Technical specifications Natural gas
ATAG iS-Series
29 30
59 59
T100
B23, B33, C13, C33, C43, C53, C63, C83, C93
60
1/3
230/50
IPX4D (B22/B33 IPX0D)
II2H3P
5
5.1
0063CQ3634
85
UMP3 15-75
10.3
see data plate LPG
A A A A AA

Installation & Servicing instructions ATAG iS-Range
8
4 Dimensions
iS 12 iS 15 iS 18 iS 24 iS 32 iS 40
Flue gas / Air intake A/B mm
Gas connection mm
CH Flow connection mm
CH Return connection mm
Condensate drain connection mm
ATAG iS-Series
System
21.5
22
22
60/100
22
CH Flow CH Return Gas
700 150
850
220225
60
220
380
440
137
343
A
B
B

Installation & Servicing instructions ATAG iS-Range
9
5 Delivery package
The delivery package of the boiler is composed as follows:
- Boiler frame;
- Boiler with cover;
- Automatic air vent (in boiler);
- Safety valve 3 bar (in boiler);
- Automatic by-pass (in boiler);
- Expansion vessel 8 litre / 1 bar (in boiler frame);
- Isolation valves with drainpoint (CH 2x,)
- Gas isolating valve;
- Fittings consisting of plugs and screws;
- Drawing template;
- Installation instructions;
- User manual;
- Warranty Card.
The following components are not present in the boiler packaging as a standard and should be included in
the installation according to the requirements:
- Flue system;
- External controls.
6 Boiler description
The ATAG iS is a room sealed, condensing and modulating CH boiler.
The boiler is equipped with a compact stainless steel heat exchanger with smooth pipes. It is a well thought-
out principle using sustainable materials.
The boiler burns gas to supply heat (natural gas and LPG versions available). This heat is transferred
in the heat exchanger to the water in the CH installation. The rapid cooling o󰀨 of the ue gases causes
condensation. This results in a very high e󰀩ciency. The condensate that is formed, has no negative impact
on the heat exchanger and it's operation, and is removed through the internal siphon. This feature requires a
condensate drain pipe connected to the drain of the building.
The boiler is equipped with an intelligent control system. The boiler anticipates on the heat demand of the
heating installation or hot water demand. This will cause the boiler to tune its capacity to the installation. This
means that the boiler will function longer and at a low level.
The boiler has been tested according to valid CE standards and has a CE certicate and >88% E󰀩cient
SEDBUK 2009.
Statement: No banned materials including asbestos, mercury, CFC's have or will not be included in
the product.

Installation & Servicing instructions ATAG iS-Range
10
7 Boiler photo components list
1 Heat exchanger
2 Ignition unit
3 Fan unit
4 Air supply damper
5 Gas valve
6 Automatic de-aerator
7 Control unit
8 Control panel
9 Circulation pump
10 Flue gas exhaust
11 Combustion air supply
12 Boiler data plate
13 Expansion vessel
14 Safety valve
15 Siphon
16 Isolation valve ow CH
T1 Flow sensor
T2 Return sensor
P1 Water pressure sensor
ATAG iS Figure 7.a
G Gas pipe
A Flow pipe CH
R Return pipe CH
C Condensation pipe
17 Isolation valve gas
18 Isolation valve return CH
T2
4
21
5
7
9
CG R
12
3
11
10
6
8
A
14
13
16 17 18
T1
P1
15

Installation & Servicing instructions ATAG iS-Range
11
8 Mounting boiler frame
Install the boiler in a boiler room in accordance to the actual local regulations BS5440-2:2000.
The installation location of the boiler has to be, and remain, frost-free. The boiler casing is splash water tight
(IPX4D) and is suitable to be installed in e.g. a bathroom.
It is NOT necessary to have a purpose provided air vent in the room or internal space in which the boiler is
installed. Neither is it necessary to ventilate a cupboard or compartment in which the boiler is installed, due
to the extremely low surface temperature of the boiler casing during operation. Therefore the requirements of
BS 6798, Clause 12, and BS5440:2 may be disregarded.
The boiler can be mounted practically to any wall with the wall frame and the enclosed xing equipment. The
wall must be at and of su󰀩cient strength in order to be able to carry the boiler weight with its water content.
Above the boiler there must be at least 175 mm working space in order to be able to t a horizontal
concentric ue system to the rear (See chapter 9.8 for more ue options). Make sure there is su󰀩cient
service space arround the boiler according gure 8.a. The location of the boiler can be determined by using
the template.
The wall frame allows the possibity to pre-t the complete heating system before tting the boiler. Also the
ue system can be prepared. Finally tting of the ue system is done after tting the boiler. See next page for
all options for connection the heating, condensate, ue and gas installation.
Before hanging the boiler to the boiler frame remove the front panel of the boiler rst. The front panel is also
the air cabinet and is attached to the boiler case with 2 fasteners (A and B) (see gure 8.a).
Note that there is an earth cable to disconnect when removing the boiler front panel. Free space for
removing the connector is about 400 mm. Remember to connect this earth cable when placing back
the boiler front panel and take care the wire does not get stuck between front panel and boiler.
See chapter 9.8 for further procedure to t the boiler onto the boiler frame.
Service dimensions (in mm) Figure 8.a
100
2.5 2.5
400
Service space
Service space
175
Bayonet catch
A
B

Installation & Servicing instructions ATAG iS-Range
12
8.1 Wall frame
- Position the boiler frame against the wall using the template and a level.
- Use the level for horizontal positioning and checking the vertical position.
- Drill 4x ø10mm holes, 60mm deep
- Press the nylon wall plug (ø10x55mm) in the holes
- Mount the boiler frame to wall with the 4 coach screws (ø8x60mm) using a 13mm wrench
The boiler frame allows pipe work to be installed behind the boiler.
Note that there are free spaces on the left and right of the expansion vessel. Do not guide pipe work
in front of the expansion vessel. The pipe work must be installed at least 10mm inside the front of the
frame.
ATAG i-Serie template and boiler frame Figure 8.1.a
= free space for piping

Installation & Servicing instructions ATAG iS-Range
13
9 Connecting boiler
The boiler has the following connection pipes;
- The central heating pipes.
The boiler is provided with isolation valves on the ow and return pipe to which the installation can be
connected by means of 22mm compression ttings;
- The gas pipe.
The boiler is provided with an isolation gas valve to which the gas line can be tted with 22mm
compression tting;
- The condensation drain pipe.
It consists of a 25mm exible plastic pipe. The drain pipe can be connected to this by means of an open
connection;
- The ue gas exhaust system and air supply system.
It consists of a concentric connection 60/100 mm.
See following chapters for detailed information regarding each connection.
It is advisable to clean all of the boiler’s connecting pipes and/or to power ush the installation
before connecting it to the boiler.
9.1 Central heating system
Connect the central heating system according to the current regulations.
The boiler pipes can be connected to the installation by means of 22mm compression ttings. For connecting
to thick-walled pipe (welded or tted), adapters should be used.
The boiler has a self-adjusting and self-protecting control system for the load. This involves checking the
temperature di󰀨erence between the ow and return water. Table 9.1.a shows the water displacement the
circulation pump can deliver for a particular installation resistance.
If the installation resistance is higher than the value stated, the control system will adjust the load until a
temperature di󰀨erence between ow and return water is reached that is acceptable for the control system.
When the temperature di󰀨erence still remains too high the boiler will switch itself o󰀨 and wait until the high
temperature di󰀨erential between the ow and return water has decreased again.
The control system will, if an unacceptable temperature di󰀨erence is detected, repeatedly try to establish a
water ow. If this does not succeed, the boiler will block itself (code 154).
Pump type
Boile
r
type l/min l/h kPa mba
r
Grundfos
iS 12 UPM3 15-75 7.6 460 25 250
iS 15 UPM3 15-75 9.5 570 25 250
iS 18 UPM3 15-75 11.4 680 25 250
iS 24 UPM3 15-75 15.2 910 25 250
iS 32 UPM3 15-75 20.3 1220 20 200
iS 40 UPM3 15-75 25.3 1520 20 200
Water flow rate at T 20°C Permissible installation resistance
Installation resistance table 9.1.a

Installation & Servicing instructions ATAG iS-Range
14
The boiler is NOT equipped with a built-in internal lter.
Advice: ATAG Heating Technology Ltd recommend the installation of an in-line lter installed into the
heating return as close to the boiler as possible. ATAG Heating Technology Ltd recommend the use
of the:
ATAG iGuard Magnetic lter 22mm (Plastic) FC000100, (Brass) FC000200, 28mm (Brass) FC000250.
The boiler is not suitable for installations that are equiped with “open” expansion tanks.
Additives in the installation water are only permitted in consultation with the country distributor. See
chapter 9.3 for detailed information.
9.2 Expansion vessel
The iS boilers are featured with a built-in expansion vessel with a capacity of 8 litres and a pre-pressure
charge 1 bar. If the expansion vessel size is insu󰀩cient for the CH system, an additional expansion must be
installed. The additional expansion vessel should, together with the built-in expansion vessel, be sized to the
water content of the installation. The pre-pressure charge depends on the height of the installation above the
installed expansion vessel. See Table 9.2.a.
The (additional) expansion vessel should be connected as closely as possible in the return pipe near
the boiler.
Installation height above the expansion vessel pre-charge pressure of the expansion vessel
5m 0,5 bar
10m 1,0 bar
15m 1,5 bar
table 9.2.a
The pressure relief valve outlet is combined with the condensate outlet (see gure 9.8.e on page 29).
9.3 Water quality
Fill the installation with mains cold water.
In most cases, a heating system can be lled with water according to national standards for water and
treatment of this water is not necessary.
In order to avoid problems with the CH-installations, the quality of the lling water has to meet the
specications mentioned in table 9.3.a:
If the lling water does not meet the required specications, you are advised to treat the water to such an
extent that it does meet the required specications.
The warranty becomes invalid, if the installation is not being ushed and/or the quality of the lling
water does not meet the specications recommended by ATAG Heating Technology Ltd. Always
contact ATAG Heating Technology Ltd in advance, if things are not clear or you wish to discuss any
deviations. Without approval, the warranty becomes invalid.
Installation:
- The use of groundwater, demi-water and distilled water is prohibited. (on the next page you will nd an
explanation of these denitions)
- If the mains water quality meets the specications mentioned in table 9.3.a, you can start ushing the
installation before installing the device.
- Whilst ushing, corrosion products (magnetite), tting products, cutting oil and other undesirable products
have to be removed.
- Another possibility is to remove the pollution by installing a lter. The lter type has to t the type and
grain size of the pollution. ATAG Heating Technology Ltd recommends lter usage.
- In this case, the whole piping system should be taken into consideration.
- The CH-installation has to be properly vented before using the system. For that purpose, we refer to the
commissioning chapter.

Installation & Servicing instructions ATAG iS-Range
15
- If a regular water top up is required (>5% on an annual basis), then there is a structural problem and
an installer has to solve the problem. Regularly adding fresh water to the system also adds additional
calcium and oxygen implying that magnetite and calcium residues can continue. The result may be
blockages and/or leakages.
- The use of anti-freeze and other additives requires periodical quality checks of the lling water in
accordance with the period laid down by the additives supplier.
- Chemical additions are to be avoided and should only be used after ATAG Heating Technology Ltd has
approved their corresponding use.
- Should you wish to achieve the required water quality by using chemical additives, then this is your own
responsibility. The warranty on the product delivered by ATAG Heating Technology Ltd expires, if the
water quality does not meet ATAG Heating Technology's specications or the chemical additives have not
been approved by ATAG Heating Technology Ltd.
- On installation and during additions or changes at a later stage, ATAG Heating Technology Ltd
recommends to keep a record of the type of water used, its quality at the time, and if applicable, which
additives and quantities were added.
Parameter Value
Water type Potable water
Softened water
pH 6.0-8.5
Conductivity (at 20°C in µS/cm) Max. 2500
Iron (ppm) Max. 0.2
Hardness (°dH / ppm):
Installation volume/capacity
<20 l/kW
1-12 °dH / 17-214 ppm
Installation volume/capacity
>=20 l/kW
1-7 °dH / 17-125 ppm
Oxygen No oxygen di󰀨usion allowed during operation.
Max. 5% lling water addition annually
Corrosion inhibitors Refer to Additives Attachment
pH increasing or lowering agents Refer to Additives Attachment
Anti-freeze additives Refer to Additives Attachment
Other chemical additives Refer to Additives Attachment
Solid substances Not allowed
Residues of processing water not forming part of the
drinking water
Not allowed
table 9.3.a
Water type denition:
Potable water: Tap water compliant with the European drinking water guideline:
98/83/EG dated 3 November 1998.
Softened water: Water with partly de-ionised calcium and magnesium.
Demi-water: Virtually completely demineralised water (very low conductivity)
Distilled water: Water no longer containing minerals.

Installation & Servicing instructions ATAG iS-Range
16
9.4 Heating systems with plastic pipes
When connecting or using an underoor heating system, designed with plastic pipes, or plastic pipes are
used elsewhere in the installation, one should ensure that the plastic pipes used comply with the DIN
4726/4729 standard. It is set out in this standard that the pipes may not have oxygen permeability higher
than 0.1 g/m³.d at 40°C. If the system does not comply with this DIN standard, the underoor heating
component will have to be separated from the central heating appliance by means of a plate exchanger.
No recourse can be made to the terms of the warranty in the event of failure to observe the
regulations pertaining to plastic underoor heating pipes.
9.5 Gas connection in general
The local gas supplier should be consulted, at the installation planning stage, in order to establish the
availability of an adequate supply of gas. An existing service pipe must NOT be used without prior
consultation with the local gas supplier.
ATAG supplies boilers suitable for natural gas only and boilers for LPG only. Verify the identication
plate on the boiler if the boiler is suitable for the gas kind on site. The boilers cannot be converted to
another kind of gas.
Make sure that the gas pipe work does not contain dirt, particularly with new pipes.
The complete installation MUST be tested for gas tightness and purged as described in the above
code.
The boiler connection is provided with an isolation valve with 22mm compression tting, into which the gas
line can be tted.
9.5.1 Natural gas connection (NG)
The gas supply must comply to the current Gas Safety, Installation & Use Regulations, in accordance with
BS.6891.
The nominal inlet working gas pressure measured at the appliance should be 21 mbar +/- 2 mbar for Nat
gas (G20). Allowing for the acceptable pressure loss of 1 mbar across the installation pipework, it can
be assumed that a minimum permitted operating pressure of 18 mbar will be delivered to the inlet of the
appliance. (Reference BS 6400-1 Clause 6.2 Pressure Absorption). When tested at the gas valve, the
pressure drop from the meter to the gas valve must not be more than 3.8 mbar.
9.5.2 Propane gas connection (LPG)
The LPG installation has to comply with British Standard 813 and Domestic Gas Installations
Installing of a LPG installation should only be done by a registered LPG installer.
The tank must be provided with a high pressure regulator with a minimum capacity of 24 kg/h to reduce
the tank pressure from 5 to 1,5 bar. The 1,5 bar high pressure gas line should have a minimum diameter of
15mm. In the high pressure gas line a house pressure regulator must be installed. When tested at the gas
valve, the pressure drop from the pressure regulator to the gas valve must not be more than 3.7 mbar.

Installation & Servicing instructions ATAG iS-Range
17
9.5.3 House pressure regulator
Each gas appliance which is connected to the propane installation must be provided with its own
house pressure regulator. The house pressure regulator is a third party delivery.
The house pressure regulator must have a minimum capacity of 10 kg/h / 30 mbar and a CE certication.
ATAG advices to install the house pressure regulator as close as possible to the boiler. When placing the
regulator inside, a discharge drain of ø6mm must be installed. The discharge drain must be directed outdoor.
In case of a discharge the gasses will go outside.
If tting the regulator outside the regulator should be protected against inuences of the weather. The (de-)
aeration must be positioned downwards (see gure 9.5.3.a).
ATAG advices to install measure points on all gas line parts to have the possibility to check for pressure loss.
Pre-pressure must be adjusted to 30 mbar by means of the house pressure regulator. The maximum
permitted closing pressure may be 5 mbar higher than the maximum pre-pressure.
A too high closing pressure in the low pressure gas line can be caused by a high resistance or jam in this gas
line. When the closing pressure keeps increasing the valve in the regulator is not closing correctly. In this
case the regulator should be replaced.
9.5.4 Dimensioning of the low pressure gas line
The gas line from the house pressure regulator to the boiler must have the dimensions according the table
below.
9.5.5 De-aerating the LPG tank
When placing a new or revised LPG tank the tank must alway be de-aerated.
ATAG advices to inform the gas supplier that a central heating boiler is connected to the LPG tank. For the
boiler it is absolutly necessary that the tank is free of air. When not the boiler will give ignition problems and
will not function.
ATAG advices to measure the content of O2. This value should be lower than 1,3%. Contact the gas
supplier in case of doubt.
Boiler type iC 24 iC 28 iC 36 iC 40 iC Economiser 27 iC Economiser 35 iC Economiser 39
Diameter gas line mmmm m m m
ø15mm 3 - - - - - -
ø22mm 30 18 18 18 18 18 18
ø28mm - 30 30 30 30 30 30
example propane installation gure 9.5.3.a

Installation & Servicing instructions ATAG iS-Range
18
9.6 External DHW cylinder
ATAG 3-port external diverter valve kit including the ONE controller (CT500111) used with a vented
hot water cylinder.
The ATAG 3-port diverter valve is to be tted external to the boiler on the system pipework with the electrical
wiring routed back to the wiring loom diverter valve connection within the iS boiler with a connection plug and
wire included with in the 3-port diverter valve kit.
The installation will use the cylinder sensor supplied within the 3-port diverter valve kit to control the hot
water temperature. Therefore no other cylinder thermostat is required.
The ONE controller will control the heating and hot water time and temperature requirements.
The weather compensation for heating will be controlled by the boiler and ONE controller via the internet
connection and postal code weather data. An optional outside sensor (ARZ0055U) can be added to the
3-port diverter valve kit to sense the outside temperature specically for the individual property.
Fitting the cylinder temperature sensor
The cylinder sensor may be tted into a sensor pocket if available, please refer to the cylinder manufactures
instructions. If there is no sensor pocket, as found with foam covered cylinders then the following steps
should be followed.
1. Mark a rectangular section of approximately 50mm (w) x 100mm (h) about one third of the cylinder height
up from the bottom of the cylinder.
Caution: Cut carefully. Do not pierce the wall of the cylinder or cut away any metal insulation outer
casing.
2. Using a sharp knife, carefully cut through the insulation, remove and retain the piece of insulation.
3. Clear o󰀨 any excess material from the surface of the cylinder to ensure the best contact.
4. Place the sensor in position on the cylinder body and hold in place with aluminium tape and where
available apply heat conductive paste.
5. Replace the previously removed insulation material
6. Secure the insulation in place with suitable tape or strapping.
Wiring of components
Connect the 3-port diverter valve to the spare 3-port valve connector on the wiring loom.
Connect the cylinder sensor with the yellow connector to the yellow DHW volt free position and the ONE
control wires with the blue connector to the blue BUS volt free position on the back of the control panel.
Figure 9.6.a

Installation & Servicing instructions ATAG iS-Range
19
3-port diverter valve
Install the 3-port diverter valve on the system pipework with the valve ports is the following orientation, AB
port iS System boiler, A port hot water cylinder & B port heating system.
ATAG 3-port external diverter valve kit including the ONE controller (CT500111) used with an
unvented hot water cylinder.
The ATAG 3-port diverter valve is to be tted external to the boiler on the system pipework with the electrical
wiring routed back to the wiring loom diverter valve connection within the iS boiler with a connection plug and
wire included with in the 3-port diverter valve kit.
The installation will use the cylinder sensor supplied within the 3-port diverter valve kit to control the hot
water temperature. Therefore no other cylinder thermostat is required.
The ONE controller will control the heating and hot water time and temperature requirements.
The weather compensation for heating will be controlled by the boiler and ONE controller via the internet
connection and postal code weather data. An optional outside sensor (ARZ0055U) can be added to the
3-port diverter valve kit to sense the outside temperature specically for the individual property.
The installation may require altered wiring of the dual thermostat (depending on the cylinder the
manufacturer) to only use the high limit thermal cut-out of the dual thermostat.
The high limit thermal cut-out of the dual thermostat MUST be wired to interrupt the power to the 2-port valve
supplied with the unvented cylinder.
Fitting the cylinder temperature sensor
The cylinder sensor is to be tted into a sensor pocket of the unvented cylinder along with the dual
thermostat supplied with the unvented cylinder.
Wiring of components
Connect the 3-port diverter valve to the spare 3-port valve connector on the wiring loom.
Connect the cylinder sensor with the yellow connector to the yellow DHW volt free position and the ONE
control wires with the blue connector to the blue BUS volt free position on the back of the control panel.
a.
d.
c.
a.
b.
c.
BA
AB
AB
B
AB
A B
A
a. brown
b. blue
c. black
d. grey
Junction box (not included)
3-port valve
230V
AB: iS System boiler
A: DHW Cylinder
B: Heating system
ATAG outside sensor (optional)
Cylinder sensor
ATAG One controller
1
2
3
4
5
6
7
8
9
10
11
12
Volt free
terminals
DO NOT CONNECT 230 VOLT
Figure 9.6.b

Installation & Servicing instructions ATAG iS-Range
20
2 port zone valve & dual thermostat (supplied with unvented cylinder)
The 2-port zone valve must be installed in the primary ow pipework between the 3-port valve and the
cylinder connection as per the following diagram and G3 unvented hot water requirements.
The 230v mains power supply MUST be wired only to the high limit thermal cut-out of the dual thermostat
and be wired to interrupt the power to the motor of the 2-port valve as per electrical diagram below.
3-port diverter valve
Install the 3-port diverter valve on the system pipework with the valve ports is the following orientation, AB
port iS System boiler, A port hot water cylinder & B port heating system.
a.
d.
c.
a.
b.
c.
BA
AB
AB
B
AB
A B
A
a. brown
b. blue
c. black
d. grey
Junction box (not included)
3-port valve
230V
AB: iS System boiler
A: DHW Cylinder
B: Heating system
ATAG outside sensor (optional)
Cylinder sensor
ATAG One controller
1
2
3
4
5
6
7
8
9
10
11
12
Volt free
terminals
DO NOT CONNECT 230 VOLT
Figure 9.6.d
Figure 9.6.c
M
N L
N
L
NL E
Safety limit
thermostat
Dual thermostat
Cylinder
thermostat
NOT REQUIRED
USE CYLINDER
SENSOR SUPPLIED
Remove any links between
safety limit thermostat and
cylinder thermostat within the
dual thermostat
Boiler
mains in
230 V Mains
supply