Glowworm 30sxi Operating manual

2000225013B.03.02
This is a Cat I2H Appliance
Reference in these instructions to British Standards and Statutory
Regulations/Requirements apply only to the United Kingdom.
For Ireland the rules in force must be used.
To be left with the user
10081
Instructions for Use
Installation and Servicing
30sxi
High Efficiency
Condensing System Boiler
G.C. No. 41-047-62
Hepworth Heating Ltd.,
Nottingham Road, Belper, Derbyshire. DE56 1JT
General/Sales enquiries:
Tel: [phone] Fax: [phone]
One Contact Local Service
Customer Services:
Tel: [phone]
Fax: [phone]
Guarantee Registration
The instructions consist of three parts, User, Installation and Servicing Instructions, which includes the Guarantee Registration
Card. The instructions are an integral part of the appliance and must, to comply with the current issue of the Gas Safety
(Installation and Use) Regulations, be handed to the user on completion of the installation.
REGISTER YOUR GLOW-WORM APPLIANCE
CALL 0208 247 9857
Thank you for installing a new Glow-worm appliance in your home.
Glow-worm appliances' are manufactured to the very highest standard so we are pleased to offer our customers’ a
Comprehensive Guarantee.
This product is guaranteed for 24 months from the date of installation or 30 months from the date of manufacture,
whichever is the shorter, for parts. In addition this product is guaranteed for 12 months from the date of intallation or
18 months from the date of manufacture, whichever is the shorter, for labour.
The second year of the parts guarantee, from the beginning of the 13th month onwards after installation or
manufacture, is conditional upon the boiler having been serviced by a CORGI registered gas installer, in accordance
with the manufacturer's recommendations. We strongly recommend regular servicing of your gas appliance, but where
the condition is not met, any chargeable spare parts or components issued within the applicable guarantee period still
benefit from a 12 month warranty from the date of issue by the manufacturer.
We recommend you complete and return as soon as possible your guarantee registration return literature, supplied in
the document envelope.
If your guarantee registration return literature is missing you can obtain a copy or record your registration by
telephoning the Heatcall Customer Service number 01773 828100.

2
2000225013B
Important Information
SERVICING
INSTRUCTIONS
CONTENTS DESCRIPTION SECTION PAGE No.
INSTRUCTIONS
FOR USE
INSTALLATION
INSTRUCTIONS
Important Information 2
Operating the Boiler 4
General Information 1 5
Boiler Location 2 8
Flue Location and Ventilation 3 9
Heating System 4 10
Domestic Hot Water System 5 12
Installation Preparation 6 12
Flue Preparation 7 14
Gas/Water Connections and Boiler Fixing 8 16
Safety Valve Discharge and
Condensate Connections 9 17
Electrical Connections 10 18
Commissioning 11 20
Servicing 12 22
Fault Finding 13 27
Replacement of Parts 14 29
Spare Parts 15 39
General
This condensing system boiler is able to provide central from a
sealed water system with a fully indirect cylinder. The central
heating water temperature can be adjusted on the boiler.
Once the controls are set the boiler operates automatically.
A frost protection program is also included.
Please read these instructions and follow them carefully for the
safe and economical use of your boiler.
Gas Category
This boiler is for use only on Natural Gas (G20).
Gas Safety (Installation and Use) Regulations
In your own interests and that of safety, it is the Law that ALL
gas appliances are installed by a competent person in
accordance with the current issue of the above regulations.
Gas Testing and Certification
The boiler is tested and certificated for safety and performance.
It is, therefore, important that no alteration is made to the boiler
unless approved, in writing, by Hepworth Heating Ltd.
Any alteration not approved by Hepworth Heating Ltd., could
invalidate the certification, boiler warranty and may also infringe
the current issue of the statutory requirements.
CE Mark
This boiler meets the requirements of Statutory Instrument, No.
3083 The Boiler (Efficiency) Regulations, and therefore is
deemed to meet the requirements of Directive 92/42/EEC on
the efficiency requirements for new hot water boilers fired with
liquid or gaseous fuels.
Type test for purposes of Regulation 5 certified by: Notified
body 0086.
Product/production certified by: Notified body 0086.
The CE mark on this appliance shows compliance with:
1. Directive 90/396/EEC on the approximation of the laws of the
Member States relating to appliances burning gaseous fuels.
2. Directive 73/23/EEC on the harmonisation of the Laws of the
Member States relating to electrical equipment designed for
use within certain voltage limits.
3. Directive 89/336/EEC on the approximation of the Laws of
the Member States relating to electromagnetic compatibility.
Control of Substances Hazardous to Health
Under Section 6 of The Health and Safety at Work Act 1974, we
are required to provide information on substances hazardous to
health.
The adhesives and sealants used in this appliance are cured
and give no known hazard in this state.
Insulation Pads.
These can cause irritation to skin, eyes and the respiratory tract.
If you have a history of skin complaint you may be susceptible
to irritation. High dust levels are usual only if the material is
broken.
Normal handling should not cause discomfort, but follow normal
good hygiene and wash your hands before eating, drinking or
going to the lavatory.
If you do suffer irritation to the eyes or severe irritation to the skin
seek medical attention.

32000225013B
Important Information
Spare Parts
REMEMBER, When replacing a part on this appliance, use only
spare parts that you can be assured conform to the safety and
performance specification that we require. Do not use
reconditioned or copy parts that have not been clearly authorised
by Hepworth Heating Ltd.
Manual Handling Guidance
During the appliance installation and the replacement of the
heat exchanger it will be necessary to employ caution and
assistance whilst lifting as the appliance or component exceeds
the recommended weight for a one man lift.
In certain situations it may be required to use a mechanical
handling aid.
Take care to avoid trip hazards, slippery or wet surfaces.
Gas Leak or Fault
If a gas leak or fault exists or is suspected, turn the boiler
mains electrical supply off and turn off the gas supply at the
meter. Consult your local gas company or your local installation/
servicing company.
Electrical Supply Failure
The boiler must be earthed.
The boiler will not work without an electrical supply.
Normal opration of the boiler should resume when the electrical
supply is restored.
Reset any external controls, to resume normal operation of the
central heating.
If the boiler does not resume normal operation turn the mains
reset switch off and on. If the boiler does not resume normal
operation and an 'F9' fault code is indicated on the digital
display, the overheat stat may have operated. The overheat
stat would only operate under abnormal conditions and, under
these circumstances; it would be advisable to consult your
installation/servicing company.
Maintenance and Servicing
If this appliance is installed in a rented property there is a duty
of care imposed on the owner of the property by the current
issue of the Gas Safety (Installation and Use) Regulations,
Section 35.
Servicing/maintenance should be carried out by a competent
person in accordance with the rules in force in the countries of
destination.
To obtain service, please call your installer or Heatcall (Glow-
worm’s own service organisation) using the telephone number
on the front cover of this booklet.
Please be advised that the installation engineer on completion
of commissioning and servicing should complete the ‘Benchmark’
logbook.
All CORGI Registered Installers carry a CORGI ID card, and
have a registration number. Both should be recorded in your
boiler Logbook. You can check your installer is CORGI registered
by calling CORGI direct on: 01256 372300.
Boilers Installed in a Compartment or
Cupboard
If the boiler is fitted into a compartment or cupboard, it does not
require any ventilation openings. Do not use the compartment
or cupboard for storage.
Protection Against Freezing
The boiler has a built in frost protection programme as long as
the electricity and gas are left switched on.
This device operates the burner and system pump when the
temperature inside the boiler falls to 3°C.
Any other exposed areas of the system should be protected by
a separate frost thermostat.
If the mains electricity and gas are to be turned off for any long
periods during severe weather, it is recommended that the
whole system, including the boiler, should be drained to avoid
the risk of freezing. Make sure that, if fitted, the immersion
heater in the cylinder is switched off.
Contact your installation/servicing company as draining, refilling
and pressurising MUST be carried out by a competent person.
As a safety feature the boiler will stop working if the condensate
drain becomes blocked. During freezing conditions this may be
due to the forming of ice in the condense drain external to the
house. Release an ice blockage by the use of warm cloths on
the pipe. The boiler should then restart. Contact your installation/
servicing company if the fault persists.
Clearances
If fixtures are positioned close to the boiler, space must be left
as shown in diagram 2.1. Enough space must also be left in
front of the boiler to allow for servicing.
Boiler Casing
Do not remove or adjust the casing in any way, as incorrect
fitting may result in incorrect operation or failure to operate at all.
Pluming from flue terminal
Like all condensing boilers this appliance will produce a plume
of condensation from the flue terminal in cool weather. This is
due to the high efficiency and hence low flue gas temperature
of the boiler. It is normal and not a fault indication
Cleaning
This appliance contains metal parts and care should be taken
when handling and cleaning with particular regard to edges.
The boiler casing can be cleaned using a mild liquid detergent
with a damp cloth, then a dry cloth to polish.
Do not use any form of abrasive or solvent cleaner as you may
damage the paintwork.
Replacement Parts
If replacement parts are required contact Heatcall (Glow-worm’s
own service organisation) using the telephone number on the
front cover of this booklet.
Please quote the name of the appliance, this information will be
on the front of the appliance.
If in doubt seek advice from the local gas company or Heatcall.

4
2000225013B
9239
Diagram 1
FASCIA
MAINS RESET
SWITCH
DIGITAL
DISPLAY
CONTROL LIGHT
CENTAL HEATING
WATER TEMPERATURE
CONTROL KNOB
Operating the Boiler
To Operate the Boiler
Sealed Water Systems
CAUTION. A sealed pressurised system must be filled and
pressurised by a competent person.
Only operate the boiler when you are sure that the system has
been filled and pressurised.
The pressure should read at least 0.7bar, anything less than this
figure could indicate a leak and you MUST contact your
installation/servicing company.
Check that the electrical supply to the boiler is ON at the external
isolator.
Set any remote controls as required.
Turn the mains reset switch to the ON position. The control light
will illuminate (green) indicating the boiler is operating.
User Controls
Turn the mains reset switch to the ON position. The control light
will illuminate (green) indicating the boiler is lit, see diagram 1.
The temperature of the central heating water can be adjusted by
turning the water temperature control knob to desired setting,
see diagram 1.
A fault is indicated by the control light flashing RED and a
flashing fault code on the digital display.
To reset:
Turn the mains reset switch anticlockwise to 0.
Wait for 5 seconds.
Turn mains reset switch clockwise to 1.
If the fault persists contact your installer/service provider.
The digital display, see diagram 1 shows the temperature of the
appliance.
To Turn the Boiler Off
There is a mains reset switch on the right hand side of the
controls fascia, which will isolate the boiler. However, it is
preferable to leave the electrical supply on whenever possible
to permit operation of the built-in frost protection and daily pump
and valve exercise.

52000225013B
C
L
FLUE
C
L
BOILER
1 General Information
Diagram 1.1
INSIDE WALL
FIXING FACE
10156
15
140
18
22
122
156 134
SAFETY
DISCHARGE
DRAIN
GAS
450
176
715
145
IMPORTANT NOTICE
The boiler is supplied in one pack, the flue and fixing jig are
supplied seperately.
This boiler is for use only on G20 natural gas.
Where no British Standards exists, materials and equipment
should be fit for their purpase and of suitable quality and
workmanship.
Refer to Manual Handling Operations, 1992 Regulations.
The installation of this boiler must be carried out by a competent
person in accordance with the rules in force in the countries of
destination.
Manufacturer’s instructions must not be taken as overriding
statutory requirements.
1.1 Sheet Metal Parts
WARNING: When installing the appliance, care should be
taken to avoid any possibility of personal injury when handling
sheet metal parts.
1.2 Statutory Requirements
The installation of the boiler MUST be carried out by a competent
person in accordance with the relevant requirements of the
current issue of:
Manufacturer’s instructions, supplied.
The Gas Safety (Installation and Use) Regulations, The Building
Regulations, The Building Standards (Scotland) Regulations
(applicable in Scotland), local Water Company Bylaws, The
Health and Safety at Work Act, Control of Substances Hazardous
to Health, The Electricity at Work Regulations and any applicable
local regulations.
Detailed recommendations are contained in the current issue of
the following British Standards and Codes of Practice, BS4814,
BS5440 Part 1 and 2, BS5449, BS5546, BS6700, BS6798,
BS6891 and BS7074 Part 1 and 2, BS7478, BS7593, BS7671.
We also suggest that you have to hand a copy of the British Gas
publication, “Guidance Notes for the Installation of Domestic
Condensing Boilers”.
Manufacturer’s notes must not be taken as overriding statutory
obligations.
BSI Certification
This boiler certificated to the current issue of EN 483 for
performance and safety.
It is important that no alteration is made to the boiler, without
permission, in writing, from Hepworth Heating Ltd.
Any alteration that is not approved by Hepworth Heating Ltd.,
could invalidate the warranty and could also infringe the current
issue of the Statutory Requirements.
77

6
2000225013B
FAN
AUTOMATIC
AIR VENT
EXPANSION
VESSEL
BURNER
HEAT EXCHANGER
PUMP
GAS
CONTROL
VALVE
DISCHARGE
OVERHEAT
CUT-OFF
RETURN
THERMISTOR
FLOW
THERMISTOR
BYPASS
C.H. INLET
FILTER
C.H.
FLOW
C.H.
RETURN
GAS
SAFETY
VALVE
DRAIN
TA P
1 General Information
Diagram 1.3
10155
Diagram 1.2
10130
SCHEMATIC LAYOUT OF BOILER
1.3 Gas Supply
The gas installation must be in accordance with the current
issue of BS6891.
The supply from the governed meter must be of adequate size
to provide a steady inlet working pressure of 20mbar (8in wg) at
the boiler.
On completion, test the gas installation for soundness using the
pressure drop method and suitable leak detection fluid, purge
in accordance with the above standard.
1.4 Technical Data
All dimensions are given in millimetres (except as noted).
See diagram 1.1 and Tables 1 and 2.
The data label is positioned on the inner door, refer to
diagram 1.2.
The Seasonal Efficiency Domestic Boilers UK (SEDBUK) is:
30 sxi: Class ‘A’.
The value is used in the UK Government's Standard Assessment
Procedure (SAP) for energy rating of dwellings. The test data
from which it has been calculated has been certified by B.S.I.
1.5 Electrical Supply
The boiler must be earthed.
All system components shall be of an approved type and all
wiring to current I.E.E. wiring regulations.
The boiler must be connected to a permanent 230V ac, 50Hz
supply.
Connection of the whole electrical system of the boiler, including
any heating controls, to the electrical supply must be through
one isolator.
Isolation should be by a double pole switched fused spur box,
with a minimum gap of 3mm for both poles. The fused spur box
should be readily accessible and preferably adjacent to the
appliance. It should be identified as to its use.

72000225013B
1 General Information
Alternatively connection can be made through an unswitched
shuttered socket and 3A fused 3 pin plug both to the current
issue of BS1363 may be used, provided they are not used in a
room containing a bath or shower.
The mains supply cable and other cables connected to the
boiler must be the PVC flexible type of at least 0.75mm2(24/
0.20mm).
The colours of three core flexible cable are, blue - neutral, brown
- live, green and yellow - earth.
The wire coloured blue must be connected to the terminal
marked ‘N’ or ‘Black’.
The wire coloured brown must be connected to the terminal
marked ‘L’ or ‘Red’.
The wire coloured green and yellow must be connected to the
terminal marked ‘E’ or ‘Green’ or the earth symbol.
1.6 Condensation Drain
A plastic drain pipe must be fitted to allow discharge of
condensate to a drain.
Condensate should, if possible, be discharged into the internal
household draining system. If this is not practical, discharge
can be made externally into the household drainage system or
a purpose designed soak away, see section 9.2 for more
details.
1.7 Heating System Controls
All heating system controls must be low voltage or potential
free.
It is recommended that a programmer and room thermostat
control the boiler.
Thermostatic radiator valves may be installed, however they
must not be fitted in a room where the room thermostat is
located.
Note: For further information, see the current issue of the
Building Regulations, approved document L1, and the
references:
1) GIL 59, 2000: Central heating system specification (CheSS)
and
2) GPG 302, 2001: Controls for domestic central heating
system and hot water. BRECSU.
1.8 Vertical Plumbing Kits
Where the heating flow and return pipes come from above the
boiler, vertical plumbing kits are available to facilitate this.
Contact Hepworth Heating for further details.
Do not route any pipes behind the boiler, unless a vertical
plumbing kit is used.
TOTAL WEIGHT
GAS CONNECTION Rc1/2(1/2in BSPT)
WATER CONNECTION 22mm. copper
ELECTRICITY SUPPLY 230V~50Hz fused 3A
ELECTRICAL RATING 60W
INTERNAL FUSE RATE Fan supply PCB 3.15AT
Main PCB 125mAT
TABLE 1
TABLE 2
BURNER
%CO2
APPROXIMATE
GAS
RATE
(after 10 mins.
from cold)
MIN MAX
9.0 ±0.2 9.0 ±0.2
0.55 3.4
15.7 95
APPLIANCE
m3/h
ft3/h
30sxi
RANGE RATING
30sxi = 33kg

8
2000225013B
2 Boiler Location
*
**
*Increase to 25mm clearance from
combustible material.
Dimensions in millimetres
Diagram 2.1
9166
†
MINIMUM CLEARANCE FROM
PERMANENT SURFACES
† A removable compartment door can be
placed at least 5mm in front of the appliance.
55
600
200 5
20 20
200
2.1 Location
The boiler is not suitable for fitting outdoors.
Any electrical switch or boiler control using mains electricity
must be positioned so that a person using a bath or shower
cannot touch it.
The boiler must be mounted on a flat wall, which is sufficiently
robust to take its weight, refer to Table 1.
2.2 Clearances
The boiler should be positioned so that at least the minimum
operational and servicing clearances are provided, see diagram
2.1.
Additional clearances may be beneficial around the boiler for
installation and servicing.
For flue installations where external access is not practicable,
consideration should be given for the space required to insert
the flue internally, which may necessitate clearance larger than
those specified in diagram 2.1.
2.4 Timber Frame Buildings
If the boiler is to be installed in a timber building it should be fitted
in accordance with the Institute of Gas Engineers document
IGE/UP/7/1998. If in doubt seek advice from the local gas
undertaking or Hepworth Heating Ltd.
2.5 Room Ventilation
The boiler is room sealed, so when it is installed in a room or
space, a permanent air vent is not required.
2.6 Cupboard or Compartment Ventilation
Due to the high efficiency and hence low casing temperature of
this boiler, cupboard or compartment ventilation is not necessary.
Leave existing air vents.

92000225013B
3 Flue Location and Ventilation
A
A
F
GE
A
G
G
G
B,C B,C
FF
K
K
K
C
G
LL
UNDER CAR PORT etc.
H,I
JD
F
K
2816
Diagram 3.3
MINIMUM SITING DIMENSIONS FOR
FANNED FLUE TERMINALS POSITION
ADIRECTLY BELOW, ABOVE OR
HORIZONTALLY TO AN OPENING,
AIR BRICK, OPENING WINDOWS,
AIR VENT OR ANY OTHER
VENTILATION OPENING. 300
BBELOW GUTTER, DRAIN/SOIL PIPE 75
CBELOW EAVES 75
DBELOW A BALCONY OR CAR PORT 200
EFROM VERTICAL DRAIN PIPES AND
SOIL PIPES 75
FFROM INTERNAL CORNERS 75*
GABOVE ADJACENT GROUND OR
BALCONY LEVEL 300
HFROM SURFACE FACING THE
TERMINAL 600*
IFACING TERMINALS 1200
JFROM OPENING (DOOR/WINDOW)
IN CAR PORT INTO DWELLING 1200
KVERTICAL FROM A TERMINAL 1500
L HORIZONTALLY FROM A TERMINAL 300
MFROM EXTERNAL CORNERS 300
M
WALL THICKNESS 'X' = 75 TO 554mm
9928
REAR FLUE - STANDARD Diagram 3.1
Diagram 3.2
SIDE FLUE - STANDARD
DISTANCE 'Y' = 335 TO 730mm - LEFT
9935
DISTANCE 'Y' = 315 TO 730mm - RIGHT
"X"
"Y"
3.1 Flue Position and Length
The standard horizontal flue is fitted onto the top of the boiler.
See diagram 3.1 and 3.2 to determine whether a standard flue
can be used.
An elevated flue system can be installed with the addition of
extension kits, see section below, Flue Options.
When extension pipes are used the flue system must be
designed to have a continuous fall to the boiler of at least 2.5o
to allow condensate to run out via the drain.
3.2 Internal Flue Installation
The flue can be installed from inside the building when access
to the outside wall face is not practicable.
3.3 Flue Options
There are various flue systems to choose from, as follows:
Standard horizontal flue pack - Pt. No. 2000460360
Vertical flue terminal Kit - Pt. No. 2000460480
2 Metre Extension Kit - Pt. No. 2000460483
1 Metre Extension Kit - Pt. No. 2000460482
0.5 Metre Extension Kit - Pt. No. 2000460481
Adjustable Flue Pipe 0-50 mm Kit - Pt. No. 2000460487
45oFlue Bend Pack - Pt. No. 2000460485
90oFlue Bend Pack - Pt. No. 2000460484
Additional accessories are available.
See Hepworth Heating “Flue Options Guide” for configurations
available.
*It may be necessary to increase this dimension to prevent
staining of adjacent walls depending on weather conditions.

10
2000225013B
3 Flue Location and Ventilation
Diagram 3.4
TERMINAL GUARD
4 Heating System
Table 4. Flow Rate
MODEL MINIMUM FLOW RATE
30sxi 12.90 litres/min.
This is equal to 20oC differential at maximum heat input.
3.4 Terminal Position
The minimum acceptable siting dimensions for the terminal
from obstructions, other terminals and ventilation openings are
shown in diagram 3.3.
The terminal must be exposed to the external air, allowing free
passage of air across it at all times.
Being a condensing boiler some pluming may occur from the
flue outlet. This should be taken into consideration when
selecting the position for the terminal.
Carports or similar extensions of a roof only, or a roof and one
wall, require special consideration with respect to any openings,
doors, vents or windows under the roof. Care is required to
protect the roof if made of plastic sheeting. If the carport
comprises of a roof and two of more walls, seek advice from the
local gas supply company before installing the boiler.
4.1 General
The boiler is for use only with sealed central heating systems.
The safety valve is an integral part of the boiler and it cannot be
adjusted.
The digital read-out on the controls fascia indicates the system
pressure when there is no demand.
The circulation pump is integral with the boiler.
4.2 Expansion Vessel
The boiler has an integral expansion vessel with a capacity of
8 litres (1.76 gallons), with a change pressure of 0.5bar.
Note: The expansion vessel volume depends on the total water
system volume and the initial system design pressure. To check
if an additional expansion vessel is required, an accurate
calculation of vessel size is given in the current issue of BS5449
and BS7074 Part 1.
4.3 Flow Rate
The flow rate through the boiler must not be allowed to fall below
that given in table 4.
The system can be fitted with a lockable balancing valve if
necessary in the main flow or return pipes shown as valve “A”
in diagram 4.1.
4.4 Bypass
The boiler is fitted with an adjustable automatic bypass. Ensure
that under no circumstances does the flow rate drop below the
figure specified, refer to table 4.
If the central heating circuit is fitted with thermostatic radiator
valves to all radiators then an additional bypass should be fitted
not less than 1.5 metres from the appliance. Refer to section
11.6
4.5 Filling the Sealed System
Provision for filling the system at low level must be made. Three
methods are shown in diagram 4.2. There must be no permanent
connection to the mains water supply, even through a non-
return valve.
NOTE: It is important that fittings used for connection to potable
water comply with the water undertakings requirements.
3.5 Terminal Guard
A terminal guard is required if persons could come into contact
with the terminal or the terminal could be subject to damage.
In a terminal guard is required, it must be positioned to provide
minimum of 50mm clearance from any part of the terminal and
be central over the terminal.
The guard should be similar to that shown in diagram 3.4.
A suitable guard is manufactured by:
Tower Flue Components
Morley Rd.
Tonbridge
Kent
TN9 1RA
Size: 280 x 280 x 270mm.

11 2000225013B
BOILER
DRAIN
POINT
'A'
FLOW CONTROL
VALVE
HEATING
CIRCUIT
RETURN
ADDITIONAL
EXPANSION
VESSEL
(if required)
* BYPASS
(if required)
METHOD 1
METHOD 2
METHOD 3
SUPPLY STOP
VALVE
SUPPLY
PIPE
HOSE
UNIONS
SERVICING
VALVE
TEMPORARY
HOSE
HEATING
SYSTEM
HEATING
SYSTEM
TEMPORARY
HOSE
HOSE
UNIONS
SERVICING
VALVE
SUPPLY
PIPE
SUPPLY STOP
VALVE
DOUBLE CHECK
VALVE ASSEMBLY
HEATING
SYSTEM
SERVICING
VALVE
SUPPLY
STOP VALVE
SUPPLY
PIPE
HOSE
UNIONS DOUBLE CHECK
VALVE ASSEMBLY
OVERFLOW
CISTERN
COMBINED
CHECK VALVE
AND VACUUM
BREAKER
PRESSURE
REDUCING
VALVE
4 Heating System
Diagram 4.1
9168
Diagram 4.2
4.6 Water Treatment
For optimum performance after installation, the boiler and its
associated central heating system should be flushed in
accordance with BS7593: 1992 using a cleanser such as
Sentinel X300 or X400, or Fernox Superfloc.
For long-term corrosion protection, after flushing, an inhibitor
suitable for stainless steel exchangers should be used. Examples
are Sentinel X100 and Fernox.
4.7 Draining Tap
A draining tap must be provided at the lowest points of the
system, which will allow the entire system to be drained.
3132
10157
* Refer to section 11.6

12
2000225013B
Diagram 6.1
9169
WALL
TEMPLATE
EXTENDED SIDE FLUE
Ø 125
900
6 Installation Preparation
5 Domestic Hot Water System
176
5.1 General
The domestic water hot service must be in accordance with the
current issue of BS5546, refer also to the current issue of
BS6700.
5.2 Domestic Hot Water Cylinder
SINGLE FEED INDIRECT CYLINDERS ARE NOT SUITABLE
AND SHOULD NOT BE USED.
The domestic hot water cylinder must be of the double feed
indirect coil type. It must be suitable for working at a gauge
pressure of 0.35bar above the safety valve setting.
6.1 Unpacking of Boiler
IMPORTANT: With regards to the Manual Handling Operations,
1992 Regulations, the following lift operation exceeds the
recommended weight for a one man lift.
Stand the boiler carton upright.
Cut and remove the securing straps and lift off the carton
sleeve. Place aside any loose components until required.
Carefully lay the boiler on its back, remove the two front casing
panel securing screws and lift off the panel from two retaining
lugs, see diagram 6.3.
Remove the two inner casing panel securing screws at the
bottom front of the panel, then lift off the two retaining lugs, see
diagram 6.3.
6.2 Wall Template
Remove the wall template from the wall mounting pack and
place in the desired position on a flat wall, giving due consideration
to boiler clearances, see section 2.2.
6.3 Flue Hole Cutting
The standard horizontal flue is designed with an internal fall
of 35mm/metre towards the boiler for disposal of condensate.
If the standard flue length alone is being used then the flue hole
of diameter 105mm can be cut in the position marked on the wall
template.
For standard side flues the horizontal flue centre line on the
wall template should be extended to the side wall, and the
vertical centre of the flue hole marked at 181mm from the back
wall.
For installations with external access, a 105mm diameter core
drill can be used.
For installations with internal access only, a 125mm diameter
core should be used.
When using extension pipes with the horizontal rear flue, a core
drill size of 125mm should be used to allow the extension pieces
to slope at 35mm/metre (2.5o) towards the boiler.
For extended side flues, the flue hole centre should be
determined by extending the dashed inclined line on the template
to the side wall. This dashed line is drawn at 35mm/metre (2.5o)
rise from the boiler. Where this line reaches the side wall, a
horizontal line should be marked. The vertical centre line of the
flue should then be marked at 181mm from the back wall, see
deagram 6.1.
To allow for the flue passing through the wall at this angle a
125mm hole should be drilled irrespective of internal or external
installation.
If necessary remove the wall template whilst drilling the flue
hole.

13 2000225013B
Diagram 6.2
10159
WALL
PLUG
SCREW
WALL
TEMPLATE
HANGING
BRACKET
FIXING JIG
PLATE
6 Installation Preparation
Diagram 6.3
10158
SECURING
SCREW (2 OFF)
FRONT
CASING
PANEL
RETAINING
LUG (2 OFF)
FIXING JIG WALL BRACKETS
(2 OFF) (Handed as shown)
SCREW
(2 OFF)
SCREW
WALL
PLUG
INNER
CASING
PANEL
LOCATING
HOLES
10068
SECURING
SCREW
(2 OFF)
6.4 Fixing Jig and Hanging Bracket Fixing
If previously removed, reposition the wall template over the flue
hole and mark the position of the fixing holes for the jig and the
hanging bracket, see diagram 6.2.
Drill the four holes and insert suitable wall plugs.
If gas and/or water pipes are to be plumbed through the rear wall
directly into the fixing jig holes, the holes must be drilled as
marked on the wall template prior to fixing of the fixing jig.
Fix the wall products to the wall using suitable screws. Locate
the jig plate between the wall brackets and secure with the
screws supplied.
6.5 Pre-Plumbing
The fixing jig can now be pre-plumbed without the boiler being
mounted if necessary. All water and gas connections are on the
fixing jig with the exception of the condense drain, the position
of which is shown on the wall template for pre-plumbing purposes.
See sections 8, 9 and 10 for details of gas, water, condensate
and electrical connections.
Do not route any pipes behind the boiler, unless a vertical piping
kit is used.

14
2000225013B
7 Flue Preparation
Diagram 7.1
Y
70
OUTSIDE
WALL
FACE
Diagram 7.2
STANDARD SIDE FLUE
9304 9313
REAR FLUE
DRILL AND
SCREW
BOILER MOUNTING
WALL
Diagram 7.3
SIDE FLUE EXTENSION
9305
DRILL AND
SCREW
7.1 Flue Length
All dimensions are in mm.
To determine flue length temporarily fit flue elbow to top of
boiler.
For rear or side flue, measure the distance from the outside wall
to the butt joint of the flue elbow fitted on top of the boiler. A
standard flue system will be suitable if the length measured ‘Y’
is less than 633mm, see diagrams 7.1 and 7.2.
If the measurement ‘Y’ exceeds 633mm then one or more
extension pipes are required.
When cutting the flue duct should be cut flush with the air duct.
7.2 Extension pipes
Refer to diagrams 7.3 and 7.4.
Note maximum permitted lengths
When extension pipes are required it should be noted that the
length of the air ducts which butt together are 960mm long and
this should be taken into account when calculating the length
that requires cutting.
For example:
Distance from outside wall to butt joint on the flue elbow ‘Y’ =
2700 mm.
Standard flue length = 633 mm.
Extension pipe length = 960 mm.
Length required of final extension pipe =
2700 - (633 + 960 + 960) = 147mm.
The length of the extension pipe in the above example to be cut
would be 147mm and would be measured from the end of the
air duct where the flue duct contains the ‘o-ring’ seal.
When cutting, the flue duct should be cut flush with the air duct
at the opposite end to where the flue duct contains the ‘o-ring’
seal.
The system is made up from a standard horizontal flue kit and
accessories. The accessories include flue extensions, bends
450and 900and fixing brackets.
The maximum permitted straight flue length is 10 metres plus
the standard horizontal flue. For each 900or 450x 2 bends fitted,
the maximum length must be reduced by 1 metre.
Note: 450x 2 bends can replace 1 x 900if necessary. When
using 900bends any horizontal extension pipe should be
inclined by a minimum of 2.50fall towards the boiler to facilitate
condense removal.
7.3 Flue Assembly
The flue assembly is a push fit design with securing collars.
Remove all burrs from cut pipes.
Diagram 7.5 shows the components supplied in the standard kit
and the flue adapter.
Having cut the air and flue ducts as described in sections 7.1-
7.2 assemble the flue as follows, the flue can be fitted externally
or entirely from inside.
Fit the rubber sealing collar behind the locating lugs on the flue
terminal, see diagram 7.5.
Push the flue assembly into the wall, externally or internally,
initially until the end of the assembly protrudes a short way from
the inside face of the wall. This will enable the inner rubber
sealing collar to be positioned and allow the flue duct to be
drawn back into the flue elbow after the boiler has been
mounted.
OUTER
RUBBER
COLLAR

15 2000225013B
7 Flue Preparation
Diagram 7.5
9931
AIR DUCT
FLUE
ELBOW
GROOVE
SEALING
COLLAR
FLUE
TERMINAL
SEALING
COLLAR
FLUE DUCT
SECURING
COLLAR (70mm)
SECURING
COLLAR
(40mm)
FLUE
ADAPTER
Diagram 7.4
EXTENDED HORIZONTAL FLUE
ELEVATED HORIZONTAL FLUE
X
Y
10083
X + Y must not exceed
10 metres plus standard
horizontal flue kit.
Reduce flue length by
1 metre for every
additional 900or 2 x 450
bends.
Total flue length must not exceed 10
metres plus standard horizontal flue kit.
Reduce flue length by 1 metre for every
additional 900or 2 x 450 bends.
7.4 Flue Attachment To Boiler
Refer to section 8 and fix the boiler in position prior to completing
the flue installation.
Refer to diagram 7.5. Secure the flue adapter in position on top
of the boiler with four torque headed screws supplied, making
sure the nib fits into the locating slot in the boiler casing to
ensure correct orientation.
Fit the flue elbow with the securing collar (length 40mm) on to
the flue adaptor.
Secure the flue elbow by tightening up the two screws on the
securing collar.
Draw flue assembly from wall, fit securing collar (length 70mm),
slide flue duct into flue elbow.
Note: If the air and flue ducts has been correctly cut to the
instructions given in sections 7.1-7.2 the rubber sealing collar
should fit flush with the outside wall, check this.
Position securing collar centrally over joint, tighten securing
screws. Drill and insert four self-tapping screws, supplied, in the
holes provided in the securing collar, see diagram 7.5.

16
2000225013B
WALL
MOUNTING JIG
GAS SERVICE
COCK
Diagram 8.1
CENTRAL
HEATING
RETURN
CENTRAL
HEATING
FLOW
GAS
SUPPLY
PIPE IN
8 Gas/Water Connections and Boiler Fixing
ON/OFF LEVER
(SHOWN CLOSED)
SAFETY
VALVE
DISCHARGE
PIPE
8.1 Gas Connection
The gas supply can be connected from below or through the
wall at the rear of the boiler, the position is shown on the wall
template.
Refer also to section 1.2.
Fit the sealing washer into the securing nut and make good the
final connection to the gas service cock on the wall mounting jig,
see diagram 8.1.
Do not subject the gas service cock to heat.
Make sure the on/off lever is accessible.
8.2 Water Connections
Provision is made for the water connections to be made from
below or through an internal wall at the rear of the boiler, the
position is shown on the wall template. Copper tailpieces are
supplied in the wall mounting pack.
Flush out the heating system before connecting to the boiler.
Make the connections to the heating system by fitting the
sealing washers into the securing nuts and make good the final
connection to the isolating valves on the wall mounting jig, see
diagram 8.1.
Do not subject the isolation valves to heat.
Make sure the drain points are accessible.
IMPORTANT: With regards to the Manual Handling Operations,
1992 Regulations, the following lift operation exceeds the
recommended weight for a one man lift.
DRAIN
POINT
(SHOWN
CLOSED)
DRAIN
POINT
(SHOWN
CLOSED)
8.3 Boiler Fixing
Having previously secured the wall mounting jig and hanging
bracket to the wall, lift the boiler into position in the following
manner.
Lean the top of the boiler slightly to the wall and position just
above the hanging bracket. Allow the boiler to slowly move
downwards until engaged in the hanging bracket.
Slowly swing the base of the boiler to the wall mounting jig
ensuring that the connections on the boiler line up with gas and
water isolation valves on the jig, see diagram 8.1. Fit sealing
washers into the securing nuts and make good the final
connections.
Please refer to condensate connection before proceeding, see
section 9.2.
Attach the flue as described in section 7.4.

17 2000225013B
Diagram 9.1
CAP
CONDENSATE
DRAIN
SPIGOT
9 Safety Valve Discharge and Condensate Connections
9.1 Safety Valve Discharge
The pipe from the safety valve must not discharge above an
entrance, window or any type of public access area.
A short discharge pipe is supplied loose in the wall mounting
pack. This must be extended, using not less than 15mm o.d.
pipe, to discharge, in a visible position, outside the building,
facing downwards, preferably over a drain, see diagram 8.1.
The pipe must have a continuous fall and be routed to a position
so that any discharge of water, possibly boiling, or steam,
cannot create any danger to persons, damage to property or
external electrical components and wiring.
To ease future servicing it is advisable to use a compression
type fitting to extend the discharge pipe.
9.2 Condensate Drain Connection
The condensate drain connection is behind the pump at the rear
of the boiler, see diagram 9.1. 21.5mm plastic overflow pipe
should be used to fit into the drain connection on the condensate
siphon and discharge condensate to a drain. The drain pipe
should have a fall of at least 2.5oaway from the boiler.
Condensate should, if possible be discharged into the household
internal drainage system. If this is not practicable, discharge
can be allowed into the external household drains or a purpose
designed soak-away.
It is recommended that any external condensate drain pipe is
insulated and also preferably of 32mm diameter, to prevent
freezing in adverse weather conditions.
The condensate is discharged periodically in ‘slugs’ by siphonic
action.
It is not necessary to provide air breaks or extra traps in the
discharge pipe as there is already a trap inside the boiler. Fitting
an extra trap may cause the boiler siphon to work incorrectly.
Refer to British Gas publication ‘Guidance notes for the
Installation to Domestic Condensing Boilers’ for advice on the
disposal of boiler condensate.

18
2000225013B
10 Electrical Connections
WARNING: This boiler must be earthed.
All system components must be of an approved type.
Electrical components have been tested to meet the equivalent
requirements of the BEAB.
Connection of the whole electrical system and any heating
system controls to the electrical supply must be through a
common isolator.
Isolation should preferably be by a double pole switched fused
spur box having a minimum contact separation of 3mm on each
pole. The fused spur box should be readily accessible and
preferably adjacent to the boiler. It should be identified as to its
use.
A fused three pin plug and shuttered socket outlet may be used
instead of a fused spur box provided that:
a) They are not used in a room containing a fixed bath or
shower.
b) Both the plug and socket comply with the 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 with a time switch or
programmer.
WARNING: UNDER NO CIRCUMSTANCES MUST ANY
MAINS VOLTAGE BE APPLIED TO ANY OF THE TERMINALS
ON THE VOLTAGE FREE HEATING CONTROLS
CONNECTION PLUG.
WARNING: This appliance must be wired in accordance with
these instructions. Any fault arising from incorrect wiring cannot
be put right under the terms of the Glow-worm guarantee.
Important: If a replacement supply cable is required it must be
purchased. Part No. S1008600.
10.1 Mains Cable
Route fitted mains cable through the cable clip as shown in
diagram 10.1.
10.2 External controls (Mains Voltage)
Gain access to the 230V interface by unclipping the fascia panel
and hinging forward, see diagram 10.2.
Remove the red link from the mains voltage heating controls
connection plug and connect and route the external control
cable as shown on diagram 10.3.
Close the fascia panel and open the rear cover of control panel,
see diagram 10.4.
Secure the external control cable in the strain relief, see
diagram 10.4.
Thread the external control cable through rear of the control
panel where the other cables exit, see diagram 10.4.
Close rear cover of control panel.
Route external control cable through the cable clip as shown in
diagram 10.1.
External control should be fitted in accordance with the rules in
force.
Refer to wiring diagram in section 13.
Diagram 10.3
PLUG
EXTERNAL
CONTROLS CABLE
Diagram 10.2
Diagram 10.1
EXTERNAL
CONTROLS
CABLE
MAINS
CABLE
CABLE
CLIP
RETAINING
LATCHES

19 2000225013B
10 Electrical Connections
10.4 Electrical Connections - Testing
Carry out preliminary electrical system checks as below:
1. Test insulation resistance to earth of mains cables.
2. Test the earth continuity and short circuit of cables.
3. Test the polarity of the mains.
Please ensure the “Benchmark” logbook is completed and left
with the user and the magnetic lighting instructions label is
placed on the surface of the boiler casing.
Diagram 10.4
CONTROL
PANEL REAR
COVER
STRAIN
RELIEF
EXTERNAL
CONTROL
CABLE
MAINS
CABLE
SECURING
SCREW (2)
9808
CABLE
EXIT

20
2000225013B
11 Commissioning
Diagram 11.2Diagram 11.1
CAP AUTOMATIC
AIR VENT PUMP
ELECTRICAL
PLUG
GAS
CONTROL
VALVE
PRESSURE TEST
POINT
11.1 Preliminaries
A competent person in accordance with the current issue of
BS6798 should carry out commissioning.
Make sure that the system has been thoroughly flushed out with
cold water without the pump in place.
Refit the pump, fill the system with water, making sure that all
the air is properly vented from the system and pump, diagram
11.1 shows drain point.
Before operating the boiler check that all external controls are
calling for heat.
11.2 System Commissioning
Fill the system until the pressure gauge registers the
recommended pressure. Clear any air locks and check for
leaks.
Check the operation of the safety valve, preferably by allowing
the water pressure to rise until the valve lifts. This should be
within +/- 0.14bar, of the preset pressure. Where this is not
possible a manual check should be carried out.
Release the cold water to the initial design pressure.
11.3 Preparation for Lighting
Isolate the boiler from the mains electrical supply.
Test for gas soundness and purge air from the gas supply. Turn
on the gas isolation valve, slot in line with the length of the valve,
see diagram 8.1.
11.4 Initial Lighting
The lighting procedure of the boiler is fully automated. Check
that all external controls are calling for heat.
With the front casing panel and inner casing panel off turn on the
mains electrical supply. Turn mains/reset button to 1 (ON). The
LCD within the digital display will flash for a moment before
displaying temperature.
The fan should start and after a few seconds the ignition will
commence.
If the burner fails to light the fan will stop. Initially this may be
due to air in the gas supply line. The boiler will have three
attempts at ignition.
Turn the mains / reset button OFF then ON and the boiler will
restart, see diagram 1 in Instructions for Use.
If the problem persists contact Heatcall Customer Services
01773 828100 (Glow-worm’s own organisation) and please
quote the name of the appliance this information will be on the
front of the appliance.
After 1st power up, the ignition sequence changes. After 1
minute stabilisation time, the boiler ‘ramps’ to maximum rate
rather than going immediately to full rate . This is an adaptive
feature to cope with small system requirements.
11.5 Gas Pressure
The gas valve is factory set and should need no adjustment. It
should be checked that the supply pressure is 20mb when the
boiler is firing at full rate. This can be achieved by checking the
inlet pressure at the tapping on the gas valve shown in diagram
11.2.
Disconnect pressure gauge.
Note that the burner pressure cannot be measured at the gas
valve as it is altered by the suction of the fan and modulated
according to demand.
Replace inner casing panel and front casing panel.
11.6 Testing - Heating System
Check that all remote controls are calling for heat. The boiler will
fire automatically. Fully open all radiator valves and flow control
valve ‘A’ if fitted, see diagram 4.1.
Balance the radiators as required and if fitted adjust valve ‘A’ to
give the required system differential. Turn off all radiators that
can be shut off by the user and check to see if less than the
maximum differential allowed of 20oC can be achieved across
flow and return.
This boiler has a built in bypass, see diagram 11.3 and 14.17.
The boiler is supplied with the bypass open half a turn. It should
not be necessary to adjust the bypass, but if required turn the
adjustment screw clockwise to close the valve, see diagram
11.3.
If the central heating circuit is fitted with thermostatic radiator
valves to all radiators then an additional bypass should be fitted
not less than 1.5 metres from the appliance.