Glowworm icon 23t Manual

This is a CAT II2H3+
appliance
USER, INSTALLATION
AND SERVICING
INSTRUCTIONS
Wall hung
combination boilers
SUPPORTED BY

2icon
Index
Note
The boiler serial number is marked on the data label attached to the inside of the outer
casing. Refer to the ‘Introduction’ section for a description of the basic functions of the boiler.
The ‘User’ section describes how to safely operate the boiler.
Mandatory warning for CEE countries
WARNING, these appliances were 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 Stockist.
Thank you in advance for your assistance.
Index
Introduction .......................................... 3
User
instructions ..................................3
Introduction .......................................... 4
Controls and lighting............................. 4
Technical data ..............................7
Installation
instructions ................................11
Clearances ......................................... 11
Terminal position ................................ 12
Heating system design....................... 13
Domestic hot water system design..... 13
Boiler connections .............................. 14
Gas connection .................................. 14
Boiler installation ................................ 15
Horizontal flue installation .................. 16
Vertical flue installation....................... 17
Flue configuration ............................... 18
Electrical connection .......................... 19
Commissioning................................... 20
Safety devices .................................... 22
Gas valve setting................................ 23
Adjustments ....................................... 23
Boiler schematic ................................. 25
Servicing
instructions ................................26
Routine cleaning and inspection......... 27
Replacement of parts ......................... 28
Schematic wiring diagram .................. 31

3
icon
User instructions
Introduction
The icon 23 t and icon 28 t boilers are wall mounted combination boilers providing central
heating and instantaneous domestic hot water.
The boilers are of the II2H3+ category for use with Natural gas (G20) as distributed in the United
Kingdom.
These instructions should be carefully followed for the safe and economical use of your boiler.
The boiler has a fan assisted balanced flue which both discharges the product of combustion to,
and draws the combustion air from the outside of the building.
ACCESSORIES
A range of accessories are available including vertical flue components. For further information,
contact you nearest Stockist.
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 by a competent person in accordance with 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 company or
your Installer/Service Provider.
BOILER CONTROLS
The control panel, located at the lower front of the boiler, allows the boiler to be started, shut down,
controlled and monitored during use, refer to ‘User Instructions’.
User
instructions

4icon
User instructions
Introduction
The icon 23 t and icon 28 t boilers are wall mounted combination boilers providing central
heating and instantaneous domestic hot water.
These instructions should be carefully followed for the safe and economical use of your boiler.
GAS LEAK OR FAULT
If a gas leak or fault exists or is suspected, turn the boiler off and consult the local gas company or
your Installer/Service provider.
IN CASE OF POWER SUPPLY FAILURE
The boiler no longer operates.
As soon as power supply is restored, the boiler will restart automatically.
IN CASE OF LOSS OF WATER IN THE SYSTEM
CAUTION: The boiler is installed as part of a sealed system which must only be drained and
filled by a competent person.
If the pressure shown on the pressure gauge is less than 1 bar the system must be filled up
immediately.
Important notice: Acentral heating system cannot operate satisfactorily unless it is properly filled
with water and unless the air initially contained in the piping systems has been properly bled off. If
these conditions are not satisfied, air noise will occur within the system.
AIR IN THE HEATING SYSTEM
Persistentair in the heatingsystemmay indicate leaks in thesystem or corrosion taking place.Call
your Installer/Service provider.
OVERHEATING SAFETY
In the event of problem, the overheat safety device causes
safety shutdown of the boiler. If this happens, call your In-
staller/Service provider.
Controls and lighting
The control panel, located at the lower front of the boiler
casing, see diagram, allows the boiler to be started, shut
down, controlled and monitored during use.
Make sure that:
— The boiler is connected to the electrical supply.
— The boiler gas service cock is open.
— The pressure gauge reads between 1 and 2 bar.
The boiler is now ready to start.

5
icon
User instructions
Controls
1 Safety lockout light
2 Summer/Winter switch
3 Heating temperature control
4 Hot water temperature control
5 Pressure gauge
6 Timeclock
7 Plastic toggles
TO START THE BOILER
Turn selector (2) to the desired Summer or Winter position.
The green lamp will light.
TO STOP THE BOILER
Turn selector (2) to the OFF position (0).
If the boiler is to be out of operation for a long period, turn off the gas service cock.
SETTING TO ‘SUMMER’MODE (HOT WATER ONLY)
Turn selector (2) to the Summer position .
Adjust the domestic hot water control (4) to the desired hot water temperature. The boiler will
operate according to the system requirements.
SETTING TO ‘WINTER’MODE (HEATINGAND HOT WATER)
Turn selector (2) to the Winter position .
Adjust the heating temperature control (3) to the desired temperature.
Adjust the domestic hot water control (4) to the desired hot water temperature. The heating
will operate according to the requirements of the timeclock and room thermostat if fitted or, will
operate according to the system requirements.
Domestic hot water always has priority over central heating.
TO PROGRAM DAILY TIMECLOCK (6) (WINTER MODE ONLY)
Set the current time, by turning the dial clockwise until the current time is shown against the
indicator “ ”.
Push in plastic toggles (7) against the time you wish the heating to come on.
The timeclock can operate in three positions: automatic “ ”, heating off “0”, and heating on “1”.
To select, move the lever to the desired position.
NOTE: In case of failure of electrical supply, timeclock does not operate, having no back-up bat-
tery. Therefore it will be necessary to adjust the current time, once electrical supply is restored.

6icon
User instructions
SAFETY LOCKOUT
If, for any reason, the boiler does not operate, check if lockout lamp (1) is lit. If so, turn
selector (2) to the reset position . The selector is spring loaded and automatically returns to
its’ previous position when released.
Note: This lamp will only light if the boiler has locked out and there is a hot water or central heating
demand at that particular time.
IMPORTANT: If the safety lockout lamp lights frequently, contact your Installer/Service Pro-
vider.
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.
Note: If there is persistent loss of system pressure, you must consult your Installer/Service Pro-
vider.
HEATING SAFETY VALVE
CAUTION: A safety valve with a discharge pipe is fitted to this boiler.
Thevalve MUST NOT BE TOUCHED exceptbyacompetent person. If the valve dischargesatany
time, switch the boiler off and isolate it from the electrical supply. Contact your Installer/Service
Provider.
SERVICING/MAINTENANCE
To ensure the continued efficient and safe operation of the boiler, it is recommended that it is
checked and serviced at regular intervals. The frequency of servicing will depend upon the instal-
lation 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.
If in doubt, contact your Installer/Service Provider.

7
icon
Technical data
Technical
data

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Technical data
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Technical data
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DIMENSIONS CONNECTIONS FOR FLUE

10 icon
Technical data
HEATING DOMESTIC
WATER
GAS
BOILER SCHEMATIC
1 By-pass
2 Pump
3 Drainvalve
4 Expansion vessel
5 Gas valve
6 Burner
7 Primary heat exchanger
8 Flue hood
9 Air pressure switch
10 Automatic air vent
11 Fan
12 Loss of water switch
13 Heating system safety valve 3 bar
14 Hydraulic 3-way valve
15 Domestic heat exchanger
16 Water valve
RETURN
FLOW
OUTLET
INLET
AVAILABLE PUMP CAPACITY
1–icon 23 t (Automatic By-Pass)
2–icon 28 t (Automatic By-Pass)
Water flow l/h
Pressure m. H2O

11
icon
Installation instructions
Installation
instructions
Clearances
The boiler can be installed with the following clearances:
5 mm either side if the boiler
600 mm to the front of the boiler
150 mm below the boiler
200 mm above the boiler
The above clearances are minimum clearances, consideration must be given to allow adequate
space for servicing.
The recommended servicing clearances are:
50 mm either side if the boiler
600 mm to the front of the boiler
150 mm below the boiler
200 mm above the boiler
CUPBOARD OR COMPARTMENT VENTILATION
The boiler can be installed in a cupboard or compartment without the need for high or low level
ventilation

12 icon
Installation instructions
AB
P
ONC
M
F
E
DIHL
G
Terminal position
The minimum acceptable spacings from the terminal to obstructions and ventilation openings are
shown in the diagram below:
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 drain pipes or soil pipes 75
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 300

13
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Installation instructions
Heating system design
The icon 23 t and icon 28 t are compatible with any type of installation.
The heating surfaces may consist of radiators, convectors or fan assisted convectors.
Pipe sectional areas shall be determined in accordance with normal practices, using the pump
curve, refer to ‘Technical Data’. The distribution system shall be calculated in accordance with the
output requirements of the actual system, not the maximum output of the boiler. However, provi-
sion shall be made to ensure sufficient flow so that the temperature difference between the flow
and return pipes is less than or equal to 20oC. The minimum flow is 420 l/h.
The piping system shall be routed so as to avoid any air pockets and facilitate permanent venting
of the installation. Bleed fittings shall be provided at every high point of the system and on all
radiators.
The total volume of water permitted for the heating system depends, amongst other things, on the
static head in the cold condition. The expansion vessel on the boiler is pressurised at 1 bar (corre-
sponding to a static head of 5m wg.) and allows a maximum system volume of 190 litres for an
average temperature of 75oC and a maximum service pressure of 3 bar. This pressure setting can
be modified at commissioning stage if the static head differs.
Provision shall be made for a drain valve at the lowest point of the system.
Where thermostatic radiator valves are fitted, not all radiators must be fitted with this type of valve
and particularly where the room thermostat is fitted.
A suitable WRC approved filling loop must be fitted to enable correct filling of the system.
In all cases, it is ESSENTIAL that the system be thoroughly flushed prior to installing the new
boiler.
Domestic hot water system design
Copper tubing or plastic HeP2O may be used for the domestic hot water system. Unnecessary
pressure losses should be avoided.
The domestic hot water supply pressure must be between 1 and 6 bar. If the pressure exceeds 6
bar, a pressure reducing valve must be fitted.
HARD WATER AREAS
In areas where the water hardness exceeds 200mg/litre, it is recommended that a suitable scale
reducing device is fitted.

14 icon
Installation instructions
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Boiler connections
Heating system connections Pipe diameter 22 mm.
Hot water system connections Pipe diameter 15 mm.
Gas connection Pipe diameter 15 mm.
AHeating return
BHeating flow
CHot water outlet
DCold water mains inlet
ESafety valve discharge connection
FGas connection
SAFETY VALVE DISCHARGE
WARNING: Itmustnotdischargeabove an
entrance or window or any type of public
access area.
Connect the safety valve discharge pipe to the valve, the discharge must be extended using not
less than 15 mm o.d. pipe, to discharge in a visible position outside the building, facing downward,
preferablyoveradrain.Thepipemusthavea continuous fall and be routedtoapositionso that any
discharge of water, possibly boiling or steam, cannot create any danger to persons, damage to
property or external electrical components and wiring. Tighten all pipe connection joints.
Gas connection
The supply from the governed meter must be of adequate size to provide a constant inlet working
pressure of 20 mbar (8 in wg).
To avoid low pressure problems, it is recommended that the supply is taken to the boiler using 22
mm pipe as far as possible.
On completion, the gas installation must be tested using the pressure drop method and purged in
accordance with the current issue of BS6891.
WARNING: Whileconnectinggasinletpipe of the boiler to thepipecomingfromgas network,
it is MANDATORY to insert a TIGHT GASKET, whose dimensions and material must be
adequate. Connection is NOT suitable for hemp, teflon strip or similar materials.
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 by a competent person in accordance with the above regulations.

15
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Installation instructions
STATUTORYREQUIREMENTS
The installation of this boiler must be carried out by a competent 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 Bylaws
— 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 sheet metal parts to avoid the possibility of personal injury.
INSTALLING THE BOILER
Prior to starting work, the system must be thoroughly flushed to eliminate any foreign bodies and
contaminents such as filings, solder, particles, oil, grease etc.
Note: Solvent products could cause damage to the system.
Boiler installation
To install the boiler, proceed as follows:
— Allowing sufficient clearances for servicing/repair,
place the template on the wall (see diagram be-
low).
— Determine the position of the flue hole and drill
hole for flue, preferably using a 120 mm core drill.
— Drill two 8mm holes for the wallplugs (supplied).
— Screwfixingscrews (supplied)intowallplugs,leave
proud by approx. 10 mm.
Note: Boiler fixing holes are keyhole type slots to al-
low easy hanging of boiler.
— Remove template.
— Hangthe boiler on thescrewsand tighten screws.
— Connect system pipework and gas connection.
Note:
1. The template is only used as a guide, it can be
removed prior to fitting the boiler.
2. Remove the plastic caps from the boiler connec-
tions prior to connecting boiler to the pipework.
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BOILER TEMPLATE

16 icon
Installation instructions
$
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3
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4
5
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Horizontal flue installation
AGasket
B90°bend
D‘O’ ring
ECollar
FClamp
HScrews
IAir inlet pipe
MExternal sealing collar
NTerminal
OScrews
PInner elbow
QInner pipe
RClip
— Fit gasket (A) onto underside of flue elbow (B).
— Fit elbow onto top of boiler ensuring it locates correctly onto fan outlet.
— Carefully insert ‘O’ ring (D) into inner elbow (P).
— Fit external sealing collar (M) onto air inlet pipe (I).
— Fit flue through hole in wall and pull up so that external collar (M) is flush against outside wall.
— Fitcollar (E) and clamp(F)to flue and assembleintoelbow (B) making surethat both inner and
outer pipes are sealed properly.
NOTE: Maximum horizontal length with no additional bends is 3m.
— Tighten up clamp using screws and nuts provided (H & G).
Note: Should it be necessary to cut the flue, always cut equal amounts from both inner and outer
pipes. Always cut the end furthest from the terminal.
For each 90oflue bend fitted, reduce overall flue length by 1 m.
For each 45oflue bend fitted, reduce overall flue length by 1/2 m.
Flue accessory Cat No.
C Flue extension kit 885117
D90
obend kit 885118
E45
obend kit 885119

17
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Installation instructions
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Vertical flue installation
AGasket
BVertical adaptor
D‘O’ ring
ECollar
LTerminal
MScrews
— Fit gasket (A) onto underside of vertical adaptor (B).
— Fit vertical adaptor onto top of boiler ensuring it locates correctly onto fan
outlet.
— Carefully insert ‘O’ ring (D) into vertical adaptor inner spigot.
—For flat roof installation, fit flat roof flashing collar (part no. 885121)
— Fit flue terminal (L) onto roof ensuring flashing makes a watertight joint.
—For pitch roof installation, fit pitch roof flashing collar (part no. 885120)
— Fit flue terminal (L) onto roof ensuring flashing makes a watertight joint.
— Fit collar (E) to vertical flue pipes and assemble between terminal (L)
and vertical adaptor (B) making sure that both inner and outer pipes
are sealed properly.
NOTE: Maximum vertical height with no bends is 4m.
— Tighten up clamp using screws provided (H).
Note: Should it be necessary to cut the flue, always cut equal amounts
from both inner and outer pipes.
For each 90oflue bend fitted, reduce overall flue height by 1 m.
For each 45oflue bend fitted, reduce overall flue height by 1/2 m.
Vertical flue kit 885116
Flue accessory Cat. No.
A Pitched roof flashing 885120
B Flat roof flashing 885121
C Flue extension kit 885117
D90
obend kit 885118
E45
obend kit 885119

18 icon
Installation instructions
Flue configuration
ATTENTION
If coaxial system would have a total length lower than 2 lin-
ear meters (n°1 additional bend = 0.5 linear meters), it will
be necessary to install the diaphragm supplied with the
gas boiler, as indicated in the figure besides
'LDSKUDJP

19
icon
Installation instructions
Electrical connection
It is important that the mains supply is wired with correct polarity: brown to LIVE, blue to
NEUTRAL.
Warning: This boiler must be earthed.
All system components must be of an approved type.
Connection of the whole electrical system and any heating system controls to the electrical supply
must be through a common isolator.
Isolation should preferably be by a double pole switched fuse spur box having a minimum contact
separation of 3 mm on each pole. The fused spur box should be readily accessible and preferably
adjacent to the boiler. It should be identified as to its use.
A fused three pin plug and shuttered socket outlet may be used instead of the fused spur box,
provided that:
a) They are not used in a room containing a bath or shower.
b) Both the plug and socket comply with the current issue of BS1363.
The mains electrical supply must be maintained at all times in order to provide domestic hot water.
DO NOT INTERRUPT THE MAINS SUPPLY TO THE BOILER WITHA TIME SWITCH OR PRO-
GRAMMER.
The icon 23 t and icon 28 t are delivered with an integral mains supply lead AND an integral
external controls lead.
EXTERNAL CONTROLS
The boiler will work for heating AS
DELIVERED without a room ther-
mostatfittedprovidedthetwowires
on the integral external controls
lead REMAIN LINKED TO-
GETHER (as supplied).
If a room thermostat is required, it
must be connected to the external
controls lead as shown below, us-
ingasuitable electrical connection.
ANYROOMTHERMOSTAT MUST
BE OF THE VOLTAGE FREE TYPE.
Note: For further information, see The Building Regulations 1991 – Conservation of fuel and power –
1995 edition – Appendix G, table 4b.
ON NO ACCOUNT MUST ANY ELECTRICAL VOLTAGE BE APPLIED TO EITHER OF THE
TERMINALS OF THE WHITE EXTERNAL CONTROLS LEAD
WARNING: This boiler must be wired in accordance with these instructions. Any fault aris-
ing from incorrect wiring may invalidate the terms of the guarantee.
BOILER
BLACK MAINS LEAD WHITE EXTERNAL CONTROL LEAD
FUSED MAINS
SPUR OR
FUSED 3 PIN
PLUG
VOLTAGE FREE
ROOMTHERMOSTAT
617
icon 23 t

icon 28 t

20 icon
Installation instructions
Commissioning
The commissioning and first firing of the boiler must only be carried out
by a competent person.
ACCESS FOR ADJUSTMENT
1. Remove the lower grille, remove two screws securing outer casing. Re-
move casing by lifting up and forwards.
2. Unscrew 6 screws securing inner casing and remove casing.
3. After commissioning, replace all items in reverse order to removal.
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 below.
FILLING THE SYSTEM
— Open isolating valves (see “Boiler connections”, items A,
BandD)and cap onautomaticairventinsidesealedcham-
ber.
— Fill system by opening system filling loop until a pressure
of between 1 and 2 bar is shown on the boiler pressure
gauge.
— Bleed each radiator until a continuous jet of water is ob-
tained.
— Do not close automatic air vent cap.
— Open various hot water taps to bleed system.
— Make sure that pressure gauge reads between 1 and 2
bar. Re-pressure as necessary.
Important: When venting air from boiler, do not touch the
schrader valve on the expansion vessel, it is NOT a vent.
STARTING THE BOILER
Before starting the boiler check that:
— The gas meter tap is open.
— The boiler gas service cock is open.
— The water isolating cocks are open.
— The boiler is connected to the electrical supply.
1 Outlet test point
2 Inlet test point
3 Vent
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