203320-3.pmd

GENERAL

icos system -

Installation and Servicing

Boiler Size

HE15

HE24

Gas supply

2H-G20-20mbar

Gas Supply Connection

Rc1/2 (1/2" BSP Female)

Injector size

Stereomatic 5.6mm dia.

Flow Connection

Central Heating

22mm copper compression

Return Connection

Central Heating

22mm copper compression

Flue Terminal Diameter

mm (in)

100 (4)

Maximum Working Pressure (Sealed Systems)

bar (lb/in

)

2.5 (36.3)

Electrical Supply / Power consumption

230 V ~ 50 Hz. / 148 W

Fuse Rating

External : 3A Internal : T3.15A L 250V

Water content

Central Heating

litre (gal)

2.0 (0.44)

Packaged Weight

kg (lb)

50 (110)

Maximum Installation Weight

kg (lb)

40 (88)

Boiler Casing Size

Height

mm (in)

687 (27)

Width

mm (in)

390 (15 3/8)

Depth

mm (in)

278 (11)

Table 1 - General Data

Note. Gas consumption is calculated using a
calorific value of 38.7 MJ/m

(1038 Btu/ft

)

gross or 34.9 MJ/m

(935 Btu/ft

) nett

To obtain the gas consumption at a different
calorific value:

a. For l/s- divide the gross heat input (kW) by

the gross C.V. of the gas (MJ/m

)

b. For ft

/h - divide the gross heat input (Btu/

h) by the gross C.V. of the gas (Btu/ft

)

Key to symbols
GB = United Kingdom IE = Ireland (Countries of destination)

PMS = Maximum operating pressure of water

= A room sealed appliance designed for connection via ducts to a
horizontal or vertical terminal, which admits fresh air to the burner
and discharges the products of combustion to the outside through
orifices which, in this case, are concentric. The fan is up stream of
the combustion chamber.

= An appliance designed for use on 2nd Family gas, Group H only.

The value is used in the UK Government's Standard Assessment Procedure (SAP) for energy rating of dwellings. The test data from
which it has been calculated have been certified by a notified body.

CAUTION.

To avoid the possibility of injury during the installation, servicing or cleaning of

this appliance care should be taken when handling edges of sheet steel components.

Boiler Size

HE15 Max

HE24 Max

HE15, HE24 Min

Boiler input 'Q' =

Nett CV

15.1

24.4

9.1

Btu/h

51,500

83,300

31,000

Gross CV

16.8

27.1

10.1

Btu/h

57,200

92,500

34,400

Boiler output 'P' =

Gas consumption

l/s (cu.ft/h)

0.43 (54.7)

0.70 (89.0)

0.26 (33.2)

C Mean water

14.6

23.4

8.8

temperature

Btu/h

50,000

80,000

30,000

C Mean water

15.5

25.1

9.6

temperature

Btu/h

53,000

85,700

32,800

Seasonal efficiency (SEDBUK) *

Band A

[90.4]%

[90.2]%

NOx classification

Class 5

Table 2 - Performance Data

203320-3.pmd

27/03/2008, 08:51

GENERAL

icos system -

Installation and Servicing

CONTENTS

Air Supply ....................................................................... 9
Benchmark Commissioning Checklist ..................... 62
Boiler Clearances ......................................................... 8
Boiler Interlocks .......................................................... 10
Boiler Exploded Diagram ...................................... 12, 13
Condensate Drain .......................................... 10, 21, 22
Electrical Connections ............................................... 29
Electrical Supply ......................................................... 10
Extension Ducts - Fitting ............................................. 19
Fault Finding ........................................................... 51-54
Flow Wiring Diagram .................................................. 32
Flue Fitting .................................................................... 17
Flue Installation ............................................................. 9
Gas Safety Regulations ................................................ 7
Gas Supply ..................................................................... 9
Installation ............................................................. 13-35
Mandatory Requirements ....................................... 7-12
Pump .......................................................................... 48
Safe Handling ................................................................ 6
Servicing ................................................................ 36-50
Short List of Parts ....................................................... 55
Thermostatic Radiator valves ................................... 10
Water and Systems ................................................ 9-12
Water Connections ..................................................... 28
Water Treatment ......................................................... 12
Wiring Diagrams ................................................... 30-32

oiler

Page

Make and model ....................................................... 5
Appliance serial no. on data badge ...................... 13
SEDBUK No. % ......................................................... 4

Controls

Time and temperature control to heating ............. 30
Time and temperature control to hot water .......... 30
Heating zone valves .............................................. n/a
TRV's ...................................................................... 10
Auto bypass ........................................................... 10
Boiler interlock ....................................................... 10

For all boilers

Flushing to BS.7593 .............................................. 12
Inhibitor .................................................................. 12

Central heating mode
Heat input ................................................to be calculated

For assistance see Technical Helpline on the back page

Page

Burner operating pressure .................................... n/a
Central heating flow temp. ...... measure and record
Central heating return temp. ... measure and record

For combination boilers only

Scale reducer ......................................................... n/a

Hot water mode

Heat input ............................................................... n/a
Max. operating burner pressure .............................. n/a
Max. operating water pressure ............................. n/a
Cold water inlet temp ............................................ n/a
Hot water outlet temp. ........................................... n/a
Water flow rate at max. setting .............................. n/a

For condensing boilers only

Condensate drain .................................................. 21

For all boilers: complete, sign & hand over to customer

For GB, to comply with Building Regulations Part L1 (Part 6 in Scotland) the boiler should be fitted in accordance with the
manufacturer's instructions. Self-certification that the boiler has been installed to comply with Building Regulations can be
demonstrated by completing and signing the Benchmark Commissioning Checklist.

icos system HE15 & HE24

Natural Gas only

Boiler size

G.C. Appliance No.

PI No.

(Benchmark No.)

HE15

41 421 99

87 BP 34

HE24

41 397 82

87 BP 34

Destination Countries:

GB, IE

BENCHMARK COMMISSIONING CHECKLIST DETAILS

NOTE TO THE INSTALLER: COMPLETE

THE BENCHMARK COMMISSIONING

CHECKLIST AND LEAVE THESE

INSTRUCTIONS WITH APPLIANCE

203320-3.pmd

27/03/2008, 08:51

GENERAL

icos system -

Installation and Servicing

BOILER WATER CIRCUIT DIAGRAM

INTRODUCTION

The icos system HE range is a cast aluminium wall mounted,
full sequence, automatic spark ignition, low water content,
fanned flue, high efficiency, condensing system gas boiler.
Note. Due to the high efficiency of the boiler a plume of water

vapour will form at the terminal during operation.

The output is fully modulating with a range of:

8.8 to 23.4 kW (30,000 to 80,000 Btu/h)

The boiler is supplied fully assembled with circulating pump,
pressure gauge, safety valve and expansion vessel.
Variable temperature control is fitted on the user control.
The boiler casing is of white painted coated mild steel with
the user controls capable of being mounted remotely from the
boiler if the option is required.
The heat exchanger is of cast aluminium.
The boiler is suitable for connection to fully pumped, sealed
water systems ONLY.
Adequate arrangements for completely draining the system
by provision of drain cocks MUST be provided in the
installation pipework.
Pipework from the boiler is routed downwards as standard,
but may be routed upwards behind the boiler using the stand-
off frame (supplied in a separate kit).

OPERATION

When there is a demand for heat, the heating system is
supplied at the selected temperature of between 30

C and

Refer also to Frame 1 - 'Boiler Water Circuit Diagram'
The boiler features a comprehensive diagnostic system which
gives detailed information on the boiler status when operating,
and performance of key components to aid commissioning and
fault finding.

SAFE HANDLING

This boiler may require 2 or more operatives to move it to its
installation site, remove it from its packaging base and during
movement into its installation location. Manoeuvring the boiler
may include the use of a sack truck and involve lifting, pushing
and pulling.
Caution should be exercised during these operations.

Operatives should be knowledgeable in handling techniques
when performing these tasks and the following precautions
should be considered:
·

Grip the boiler at the base.

Be physically capable.

Use PPE as appropriate, e.g. gloves, safety footwear.

During all manoeuvres and handling actions, every attempt
should be made to ensure the following unless unavoidable
and/or the weight is light.
·

Keep back straight.

Avoid twisting at the waist.

Avoid upper body/top heavy bending.

Always grip with the palm of the hand.

Use designated hand holds.

Keep load as close to the body as possible.

Always use assistance if required.

Expansion
vessel

Automatic
air vent

Heat
exchanger

Gas valve

Pump

Safety
relief valve

Condensate
'S' trap

Water
pressure
gauge

Sump

Fan

Burner

Flow

Gas

Condensate

drain

Discharge

pipe

nm8782

Return

203320-3.pmd

27/03/2008, 08:51

GENERAL

icos system -

Installation and Servicing

OPTIONAL EXTRA KITS

Flue Extension Ducts (1000mm long, up to 6m ).
Flue Finishing Kit.
90

Elbow Kit (Maximum 4 elbows / installation).

Powered Vertical Flue Kit 5m primary and 17m secondary
is a typical maximum length. For alternative maximum
lengths refer to Powered Vertical Instructions.
Roof Flue Kit (to a maximum of 7.5m).
High Level Flue Outlet Kits
Flue Deflector Kit
Weather Collar
Twin fluing Kit (to a maximum of 60m combined total of
flue and air ducts).
Horizontal flue terminal 600mm long.
Remote User Controls Kit.
Boiler Stand-off Kit.
Siphon Kit.
Valve Cover Kit.
Condensate Pump Kit.

SAFETY

Current Gas Safety (Installation & Use) Regulations or rules
in force.
The appliance is suitable only for installation in GB and IE and
should be installed in accordance with the rules in force.
In GB, the installation must be carried out by a CORGI
Registered Installer. It must be carried out in accordance with
the relevant requirements of the:
·

Gas Safety (Installation and Use) Regulations

The appropriate Building Regulations either The Building
Regulations, The Building Regulations (Scotland), Building
Regulations (northern Ireland).

The Water Fittings Regulations or Water byelaws in
Scotland.

The Current I.E.E. Wiring Regulations.

Where no specific instructions are given, reference should be
made to the relevant British Standard Code of Practice.
In IE, the installation must be carried out by a Competent
Person and installed in accordance with the current edition of
I.S.813 "Domestic Gas Installations", the current Building
Regulations and reference should be made to the current ETCI
rules for electrical installation.
Detailed recommendations are contained in the following British
Standard Codes of Practice:
BS. 5440:1

Flues (for gas appliances of rated input not
exceeding 70 kW).

BS. 5440:2

Ventilation (for gas appliances of rated input not
exceeding 70 kW).

BS. 5449

Forced circulation hot water systems.

BS. 5546

Installation of gas hot water supplies for
domestic purposes (2nd Family Gases)

BS. 6798

Installation of gas fired hot water boilers of rated
input not exceeding 70 kW.

BS. 6891

Low pressure installation pipes.

Health & Safety Document No. 635.
The Electricity at Work Regulations, 1989.
The manufacturer's notes must NOT be taken, in any way, as
overriding statutory obligations.

IMPORTANT. These appliances are CE certificated for safety
and performance. It is, therefore, important that no external
control devices, e.g. flue dampers, economisers etc., are
directly connected to these appliances unless covered by these
Installation and Servicing Instructions or as otherwise
recommended by Ideal Stelrad Group in writing. If in doubt
please enquire.
Any direct connection of a control device not approved by Ideal
Stelrad Group could invalidate the certification and the normal
appliance warranty. It could also infringe the Gas Safety
Regulations and the above regulations.

SAFE HANDLING OF SUBSTANCES

Care should be taken when handling the boiler insulation
panels, which can cause irritation to the skin. No asbestos,
mercury or CFCs are included in any part of the boiler or its
manufacture.

LOCATION OF BOILER

The boiler must be installed on a flat and vertical wall, capable
of adequately supporting the weight of the boiler and any
ancillary equipment.
The boiler may be fitted on a combustible wall and insulation
between the wall and the boiler is not necessary, unless
required by the local authority.
For electrical safety reasons there must be no access available
from the back of the boiler.
The boiler must not be fitted outside.
Timber Framed Buildings
If the boiler is to be fitted in a timber framed building it should
be fitted in accordance with the Institute of Gas Engineering
document IGE/UP/7:1998.
Bathroom Installations
This appliance is rated IP20.
The boiler may be installed in any room or internal space,
although particular attention is drawn to the requirements of the
current IEE (BS.7671) Wiring Regulations and, in Scotland, the
electrical provisions of the building regulations applicable in
Scotland, with respect to the installation of the boiler in a room
or internal space containing a bath or shower. For Ireland
reference should be made to the current ETCI rules for
electrical installations and I.S.813:2002.
If the appliance is to be installed in a room containing a bath or
shower then, providing water jets are not going to be used for
cleaning purposes (as in communal baths/showers), the
appliance can be installed in Zone 3, as detailed in BS.7671.
Compartment Installations
A compartment used to enclose the boiler should be designed
and constructed specially for this purpose.
An existing cupboard or compartment may be used, provided
that it is modified for the purpose.
In both cases, details of essential features of cupboard /
compartment design, including airing cupboard installation,
are to conform to the following:

BS. 6798 (No cupboard ventilation is required - see 'Air
Supply' for details).
The position selected for installation MUST allow adequate
space for servicing in front of the boiler.
For the minimum clearances required for safety and
subsequent service, see the wall mounting template and
Frame 2. In addition, sufficient space may be required to
allow lifting access to the wall mounting plate.

203320-3.pmd

27/03/2008, 08:51

GENERAL

icos system -

Installation and Servicing

BOILER DIMENSIONS, SERVICES & CLEARANCES

nm8583

all dimensions in mm (in)

The boiler connections are made on the boiler piping frame.
Refer to Frames 34 & 32.

The following minimum clearances must be maintained for
operation and servicing.

Additional space will be required for installation, depending
upon site conditions.

Side and Rear Flue
a. Provided that the flue hole is cut accurately, e.g. with a

core drill, the flue can be installed from inside the building

Front clearance
The minimum front clearance when built in to a cupboard is
5mm (

1/4

") from the cupboard door but 450mm (17

3/4

overall clearance is still required, with the cupboard door
open, to allow for servicing.

N.B. The boiler will not fit into a standard depth wall unit. In
order for it to do so the plastic fascia should be removed.
See Frame 43.

* Bottom clearance
After installation can be reduced to 5mm in an adequately
ventilated enclosed cupboard. However, 100mm must be
available for servicing.

REAR FLUE ONLY

MIN. Top clearance required = 145 mm (5

3/4

where wall thicknesses do not exceed 600mm (24").
Where the space into which the boiler is going to be
installed is less than the length of flue required the flue
must be fitted from the outside.

Installation from inside ONLY
b. If a core boring tool is to be used inside the building the

space in which the boiler is to be installed must be at
least wide enough to accommodate the tool.

SIDE FLUE ONLY

Horizontal length of flue

Top clearance

from centre line of boiler

required (MIN.)

to outside wall

Dim. A

0.5 m

160 mm (6

5/16

1.0 m

170 mm (6

11/16

)

1.5 m

185 mm (7 1

2.0 m

200 mm (

7 7/8

2.5 m

210 mm (8 1

3.0 m

225 mm (8

7/8

3.5 m

250 mm (9

7/8

4.0 m

260 mm (10

1/4

4.5 m

265 mm (10

7/16

5.0 m

275 mm (10

13/16

5.5 m

290 mm (11

3/8

6.0 m

300 mm (11

13/16

203320-3.pmd

27/03/2008, 08:51

GENERAL

icos system -

Installation and Servicing

TERMINAL

The terminal assembly can be adapted to accommodate
various wall thicknesses. Refer to Frame 12.

AIR SUPPLY

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 low surface temperatures of
the boiler casing during operation; therefore the requirements
of BS.6798, Clause 12, and BS 5440:2 may be disregarded. In
IE the requirements of I.S.813:2002 may be disregarded.

WATER CIRCULATION SYSTEM

IMPORTANT.

A minimum length of 1metre of copper pipe MUST be fitted to
both flow and return connections from the boiler before
connection to any plastic piping.
The central heating system should be in accordance with
BS.6798 and, in addition, for smallbore and microbore
systems, BS.5449.
The hot water storage cylinder MUST be of the indirect type and
should preferably be made of copper.
Single feed, indirect cylinders MUST NOT be used. The
appliances are NOT suitable for gravity central heating nor are
they suitable for the provision of gravity domestic hot water.
The hot water cylinder and ancillary pipework, not forming part
of the useful heating surface, should be lagged to prevent heat
loss and any possible freezing - particularly where pipes run
through roof spaces and ventilated underfloor spaces.

WATER TREATMENT - see Frame 6

GAS SUPPLY

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.
The boiler MUST be installed on a gas supply with a governed

meter only.
A gas meter can only be connected by the local gas supplier or

by a CORGI registered engineer. In IE by a Competent Person.
An existing meter should be checked, preferably by the gas

supplier, to ensure that the meter is adequate to deal with the

rate of gas supply required.

N.B. The principle of the 1:1 gas valve ensures that the icos

system HE range is able to deliver it's full output at inlet

pressures down to 14mb. However if dynamic pressures

below 20mb are experienced ensure this is adequate for

ALL other gas appliances in the property.

IMPORTANT.

Installation pipes MUST be fitted in accordance with BS.6891.

In IE refer to I.S.813:2002. Pipework from the meter to the

boiler MUST be of an adequate size, i.e. no longer than 20m

and not less than 15mm O.D.
The complete installation MUST be tested for gas soundness

and purged as described in the above code.

FLUE INSTALLATION

Pluming will occur at the terminal, so where possible, terminal

positions where this could cause a nuisance should be

avoided.
The flue must be installed in accordance with the

recommendations of BS.5440-1:2000. In IE refer to

I.S.813:2002.
The following notes are intended for general guidance:
1. The boiler MUST be installed so that the terminal is

exposed to external air.

2. It is important that the position of the terminal allows the

free passage of air across it at all times.

3. Minimum acceptable spacing from the terminal to

obstructions and ventilation openings are specified in

Table 3.

4. Where the lowest part of the terminal is fitted less than 2m

(6'6") above a balcony, above ground or above a flat roof to

which people have access then the terminal MUST be

protected by a purpose designed guard.

Terminal guards are available from boiler suppliers.

(ask for TFC flue guard model no. K6 - round, plastic

coated). In case of difficulty contact:
Grasslin (UK) Ltd., Tower House, Vale Rise, Tonbridge,

Kent TN9 1TB

Tel: +44 (0) 1732 359 888. Fax: +44 (0) 1732 354 445

www.tfc-group.co.uk
Ensure that the guard is fitted centrally.

5. The flue assembly shall be so placed or shielded as to

prevent ignition or damage to any art of any building.

6. The air inlet/products outlet duct and the terminal of the

boiler MUST NOT be closer than 25mm (1") to combustible

material. Detailed recommendations on the protection of

combustible material are given in BS.5440-1:2000. In IE

refer to I.S.813:2002.

IMPORTANT. It is absolutely essential to ensure, in practice,

that products of combustion discharging from the terminal

cannot re-enter the building or any other adjacent building

through ventilators, windows, doors, other sources of natural

air infiltration, or forced ventilation / air conditioning.
If this should occur the appliance MUST be turned OFF,
labelled as 'unsafe' until corrective action can be taken.

Flue Terminal Positions

Min. Spacing*

1. Directly below, above or alongside an opening

window, air vent or other ventilation opening.

300mm (12")

2. Below guttering, drain pipes or soil pipes.

25mm ( 1")*

BS5440-1 2000

75mm (3")

3. Below eaves.

25mm (1")*

BS5440-1 2000

200mm (8")

4. Below balconies or a car port roof.

25mm (1")*

BS5440-1 2000

200mm (8")

5. From vertical drain pipes or soil pipes.

25mm (1")*

BS5440-1 2000

150mm (6")

6. From an internal or external corner or to a

25mm (1")*

boundary along side the terminal.

BS5440-1 2000

300mm (12")

7. Above adjacent ground, roof or balcony level.

300mm (12")

8. From a surface or a boundary facing the terminal.

600mm (24")

9. From a terminal facing a terminal.

1,200mm (48")

10. From an opening in a car port

(e.g. door or window) into dwelling.

1,200mm (48")

11. Vertically from a terminal on the same wall.

1,500mm (60")

12. Horizontally from a terminal on the wall.

300mm (12")

Vertical Terminals

13. Above the roof pitch with roof slope of all angles. 300mm (12")

Above flat roof.

300mm (12")

14. From a single wall face.

300mm (12")

From corner walls.

300mm (12")

Table 3 - Balanced Flue Terminal Position

* Only one reduction down to 25mm is allowable per installation
otherwise BS5440-1 2000 dimensions must be followed.

203320-3.pmd

27/03/2008, 08:51

GENERAL

icos system -

Installation and Servicing

The hydraulic resistance of the boilers, at MAXIMUM OUTPUT,
with an 11

C (20

F) temperature differential, is shown in

Graph 1.

Graph 1 - Water flow rate and pressure loss

SYSTEM REQUIREMENTS

Notes

a. The method of filling, refilling, topping up or flushing

sealed primary hot water circuits from the mains via
a temporary hose connection is only allowed if
acceptable to the local water authority.

b. Antifreeze fluid, corrosion and scale inhibitor fluids

suitable for use with boilers having aluminium heat
exchangers may be used in the central heating
system.

Advice should be sought from a local water
treatment company.

BOILER CONTROL INTERLOCKS

Ideal Stelrad Group recommend that heating systems utilising
full thermostatic radiator valve control of temperature in
individual rooms should also be fitted with a room thermostat
controlling the temperature in a space served by radiators not
fitted with such a valve as stated in BS. 5449.

When thermostatic radiator valves are used, the space heating
temperature control over a living area having a heating
requirement of at least 0.9kW (3000Btu/h) of the boiler heat
output should be achieved using a room thermostat whilst other
rooms are individually controlled by thermostatic radiator
valves. A higher proportion of TRVs may be used, provided that

a bypass between the boiler flow and return is fitted, to ensure
adequate flow when all TRVs are closed.

For further information refer to the 'Good Practice Guide 143', a
publication of the Energy Efficiency Office, available from the
Building Research Establishment, Garston, Watford WD2 7JR.
Tel: +44 (0) 1923 664258.

ELECTRICAL SUPPLY

WARNING. The appliance MUST be efficiently earthed.

Wiring external to the appliance MUST be in accordance with the
current I.E.E. (BS.7671) Wiring Regulations and any local
regualtions which apply. For Ireland reference should be made
to the current ETCI rules for electrical installations.

The point of connection to the mains should be readily
accessible and adjacent to the boiler.

CONDENSATE DRAIN -

Refer to Frames 22, 23 & 24

A condensate drain is provided on the boiler. This drain must be
connected to a drainage point on site. All pipework and fittings in
the condensate drainage system MUST be made of plastic - no
other materials may be used.

IMPORTANT.

Any external runs must be insulated

The drain outlet on the boiler is standard 21.5mm (3/4") overflow
pipe.

Safety valve setting

bar

3.0

Vessel charge pressure

bar

0.5 to 0.75

System pre-charge pressure bar

None

1.0

System volume

Expansion vessel

(litres)

volume (litres)

1.6

1.8

3.1

3.7

4.7

5.5

100

6.3

7.4

125

7.8

9.2

150

9.4

11.0

175

10.9

12.9

190

11.9

14.0

200

12.5

14.7

250

15.6

18.4

300

18.8

22.1

For other system volumes
multiply by the factor across

0.063

0.074

Pressure Drop Across Boiler

(metres w

ater)

0.5

1.0

Boiler Output (kW)

8.8

11.7

14.7

17.6

20.5

23.4

Ecl 1603

203320-3.pmd

27/03/2008, 08:51

GENERAL

icos system -

Installation and Servicing

CH Return

Ecl 6053

Hose unions

Mains

water supply

Temporary hose

(disconnect after filling)

Additional

stop valve

Double check valve

assembly

(

note direction of flow

)

General
1. The installation must comply with all relevant national and

local regulations.

2. The installation should be designed to work with flow

temperatures of up to 82

3. All components of the system must be suitable for a

working pressure of 3 bar and temperature of 110

Extra care should be taken in making all connections so

that the risk of leakage is minimised.
The following components are incorporated within the

appliance:
a. Circulating pump.
b. Safety valve, with a non-adjustable preset lift pressure

of 3 bar.

c. Pressure gauge, covering a range of 0 to 6 bar.
d. An 8-litre expansion vessel, with an initial charge

pressure of 0.75 bar.

4. 'Make-up' Water. Provision must be made for replacing

water loss from the system, either :
a. From a manually filled 'make-up' vessel with a readily

visible water level. The vessel should be mounted at

least 150mm above the highest point of the system

and be connected through a non-return valve to the

system, fitted at least 150mm below the 'make-up'

vessel on the return side of the radiators.
or

b. Where access to a 'make-up' vessel would be difficult,

by pre-pressurisation of the system.

SYSTEM REQUIREMENTS - continued

The maximum cold water capacity of the system should

not exceed 143 litres, if not pressurized. However, if the

system is to be pressurized, the efficiency of the

expansion vessel will be reduced and a larger vessel (or

smaller system volume) may be necessary. If the

capacity of the vessel is not considered sufficient for

this, or for any other reason, an additional vessel MUST

be installed on the return to the boiler.
Guidance on vessel sizing is given in Frame 3.

5. Filling. The system may be filled by the following method:

Through a temporary hose connection from a 'draw-off' tap,

supplied from a service pipe under mains pressure.

Where the mains pressure is excessive, a pressure

reducing valve must be used to facilitate filling.
When installing the filling device, it must be connected as

below to fully comply with the water regulations.
This may involve the fitting of an additional WRAS approved

isolator valve to the mains supply.

i. Thoroughly flush out the whole system with

cold water.

ii. Fill and vent the system until the pressure gauge

registers 1.5 bar, and examine for leaks.

iii. Check the operation of the safety valve by raising the

water pressure until the valve lifts. This should occur

within 0.3 bar of the preset lift pressure.

iv. Release water from the system until the

minimum system design pressure is reached;

1.0 bar if the system is to be pre-pressurised.

The boiler does not normally need a bypass but at least
some radiators on the heating circuit, of load at least 10% of
the minimum boiler output, must be provided with twin
lockshield valves so that this minimum heating load is
always available. See note regarding thermostatic radiator
valves on page 10.
Note.
Systems incorporating zone valves which could completely cut
off the flow through the system, must also include a bypass.

BALANCING

1. Set the programmer to ON, for both CH and DHW. Turn

the cylinder thermostat down.
Close the manual or thermostatic valves on all radiators,
leaving the twin lockshield valves (on the radiators
referred to above) in the OPEN position.

SYSTEM BALANCING

Turn up the room thermostat and adjust these lockshield
valves to give boiler flow and return temperatures not more
than 20

C apart.

These valves should now be left as set.

2. Open all manual or thermostatic radiator valves and adjust

the lockshield valves on the remaining radiators, to give
around 15

C temperature drop at each radiator.

3. Turn up the cylinder thermostat and adjust the cylinder

balancing valve so that the cylinder achieves a maximum
flow consistent with adequate flow to the radiators. Check
that with only the domestic hot water loop in circuit a
differential temperature of 20

C across the boiler is not

exceeded.

4. Adjust the room and cylinder thermostat and programmer

to NORMAL settings.

203320-3.pmd

27/03/2008, 08:51

GENERAL

icos system -

Installation and Servicing

WATER TREATMENT

The icos system HE range has an ALUMINIUM alloy heat exchanger.

IMPORTANT. The application of any other treatment to this product may render the guarantee of Ideal Stelrad Group INVALID.

Ideal Stelrad Group recommend Water Treatment in accordance with the Benchmark Guidance Notes on Water Treatment in
Central Heating Systems.

Ideal Stelrad Group recommend the use of Fernox Copal or MB1, GE Betz Sentinel X100 or Salamander Corrosion Guard
inhibitors and associated water treatment products, which must be used in accordance with the manufacturers instructions.

For further information contact:

17. Automatic air vent.

18. Gas service cock.

19. Gas control valve.

20. Fan bracket.

21. Orifice plate.

23. Control thermistor.

24. Overheat thermostat.

25. Ignition electrode.

26. Flame detection electrode.

32. Condensate 'S' trap.

35. User control.

36. Primary controls (PCB).

39. Mains switch.

40. Spark generator.

Front casing panel.

Sealing panel.

Sump cover.

Bottom casing panel.

Flue sensing nipple.

Return pipe.

Flue manifold.

10. Interpanel.

11. Burner.

12. Combustion chamber insulation.

13. Heat exchanger

14. Injector & housing.

15. Venturi assembly.

16. Fan assembly.

BOILER ASSEMBLY - Exploded View Legend

44. Piping frame.

51. Mains connector.

53. Turret gasket kit.

57. CH return stub.

58. CH flow stub.

61. Pressure relief valve.

62. Expansion vessel.

63. Expansion vessel pipe assy.

64. Pressure gauge.

69. Pump.

70. Pump manifold.

75. Control box clamp.

94. Ignition lead.

103. Dry fire thermistor.

Fernox Manufacturing Co. Ltd,
Cookson Electronics,
Forsyth Road, Sheerwater,
Woking, Surrey.
GU21 5RZ.
Tel. +44 (0) 1799 521133 or

Sentinel Performance Solutions
The Heath Business & Technical Park
Runcorn
Cheshire WA7 4QX
Tel: 0800 389 4670
www.sentinel-solutions.net or

Salamander Engineering Ltd,
Unit 24, Reddicap Trading Estate,
Sutton Coldfield,
West Midlands
B75 7BU.
Tel. +44 (0) 121 378 0952

Notes.

1. It is most important that the correct concentration of the water treatment products is maintained in accordance with the

manufacturers' instructions.

2. If the boiler is installed in an existing system any unsuitable additives MUST be removed by thorough cleansing.

BS7593:1992 details the steps necessary to clean a domestic heating system.

3. In hard water areas, treatment to prevent limescale may be necessary - however the use of artificially softened water is

NOT permitted.

4. Under no circumstances should the boiler be fired before the system has been thoroughly flushed.

203320-3.pmd

27/03/2008, 08:51