Glow-worm Flexicom hx User Manual

Flexicom

Installation and Servicing

12hx

G.C. No. 41-315-28

15hx

G.C. No. 41-315-29

18hx

G.C. No. 41-315-42

24hx

G.C. No. 41-315-61

30hx

G.C. No. 41-315-67

35hx

G.C. No. 41-315-68

12786

High Efficiency

Condensing

Boilers

www.glow-worm.co.uk

www.glow-worm.co.uk

Guarantee Registration

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 and 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 competent

person approved at the time by the Health and Safety Executive.

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 benet 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 card.

If your guarantee registration card is missing you can obtain a copy or record your registration by

telephoning the Glow-worm Customer Service number 01773 828100.

Customer Service:

01773 828100

Technical Helpline:

01773 828300

General and Sales enquiries:

Tel. [phone]

Fax: [phone]

To register your Glow-worm appliance call:

0800 0732142

Benchmark places responsibilities on both manufacturers and installers. The purpose is to ensure that customers are provided
with the correct equipment for their needs, that it is installed, commissioned and serviced in accordance with the manufacturer’s
instructions by competent persons and that it meets the requirements of the appropriate Building Regulations. The Benchmark
Checklist can be used to demonstrate compliance with Building Regulations and should be provided to the customer for future
reference.
Installers are required to carry out installation, commissioning and servicing work in accordance with the Benchmark Code of
Practice which is available from the Heating and Hotwater Industry Council who manage and promote the Scheme.
Visit www.centralheating.co.uk for more information.

2

These instructions consist of, Installation, Servicing, Fault Finding, Replacement of Parts

and Spares. 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.

CONTENTS DESCRIPTION SECTION PAGE

Warnings 4
Important Information 4
Statutory Requirements 5

INTRODUCTION

Boiler Design 6
Safety Devices 6
Servicing, Maintenance and Spare Parts 6

Boiler Specication 1 7
Boiler Dimensions and
Hydraulic Schematic 2 8
Boiler Location, Clearances and
Ventilation 3 9
Flue Options and Terminal Clearances 4 10
Water Systems 5 12

INSTALLATION

• General 5 12

• Open Vented 5 13

• Sealed Systems 5 14
Installation Preparation 6 16
Boiler Fixing 7 17
Gas/Water and Appliance Connection 8 18
Condensate Connections 9 18
Flue Length Preparation and Installation 10 20
Electrical Connection 11 37
Commissioning 12 38

MAINTENANCE

Servicing 13 41
Fault Finding 14 46
Replacement of Parts 15 52
Spare Parts 16 57
Manual Handling 17 58
Declaration of Conformity 18 59

3

WARNINGS

Gas Leak or Fault

Turn off the gas emergency control valve immediately. Eliminate all sources of ignition, i.e.smoking, blowlamps, hot

air guns etc. Do not operate electrical lights or switches either on or off. Open all doors and windows,ventilate the

area.

Sheet Metal Parts

This boiler contains metal parts (components) and care should be taken when handling and cleaning, with particular

regard to edges.

Sealed Components

Under no circumstances must the User interfere with or adjust sealed parts.

Important Information

Gas Category

This boiler is for use only on G20 natural gas.

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
approved at the time by the Health and Safety Executive in
accordance with the current issue of these regulations.

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.

Manual Handling

With regards to the “Manual Handling Operations, 1992
Regulations”, the appliance exceeds the recommended
weight for a one man lift, refer to section 17 for more
information.
The handling of the boiler may involve lifting, pushing and
pulling, the use of a sack truck may be required.
The following handling techniques and precautions should be
considered:

- Grip the boiler at its base

- Be physically capable

- Use safety clothing where appropriate, e.g. gloves, safety
footwear.
Ensure safe lifting techniques are used

- Keep back straight.

- Avoid twisting at the waist.

- Avoid upper body/top heavy bending.

- Always grip using the palm of the hand.

- Use designated hand holds.

- Keep load as close to body as possible.

- Always use assistance if required.

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.
External wiring must be correctly earthed, polarised and in
accordance with the relevant standards.

In GB, this is BS 7671.
In IE, this is the current edition of ETCI rules.

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 common isolator and must be fused 3 Amp
maximum.
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 identied as to its use.
Alternatively connection can be made through an unswitched
shuttered socket and 3A fused 3-pin plug both to the current
issue of BS 1363, provided they are not used in a room
containing a bath or shower.
Wiring to the boiler must be PVC 85OC insulated cable, not
less than 0.75mm2 (24/0.20mm).

Testing and Certication

This boiler is tested and certicated for safety and
performance. It is, therefore, important that no alteration is
made to the boiler, without permission, in writing, by Glow­worm.
Any alteration not approved by Glow-worm, could invalidate
the certication, boiler warranty and may also infringe the
current issue of the statutory requirements.

4

Statutory Requirements

CE Mark

This boiler meets the requirements of Statutory Instrument,
No. 3083 The Boiler (Efciency) Regulations, and therefore is
deemed to meet the requirements of Directive 92/42/EEC on
the efciency requirements for new hot water boilers red with
liquid or gaseous fuels.
Type test for purposes of Regulation 5 certied by: Notied
body 0087.
Product/production certied by: Notied 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.

IMPORTANT

Where no British Standards exists, materials and equipment
should be t for their purpose and of suitable quality and
workmanship.
The installation of this boiler must be carried out by a
competent person approved at the time by the Health and
Safety Executive in accordance the rules in force in the
countries of destination.
Manufacturer’s instructions must not be taken as overriding
statutory requirements.

Statutory Requirements

In GB, the installation of the boiler must comply with the

requirements of the current issue of BS6798 and be carried
out by a competent person, approved at the time by the
Health and Safety Executive, as described in the following
regulations:
The manufacturer’s instructions supplied.
The Gas Safety (Installation and Use) Regulations.
The appropriate Buildings Regulations either The Building
Regulations, The Building Regulations (Scotland),The
Building Regulations (Northern Ireland).

The Water Supply (water ttings) Regulations 1999 and water
byelaws 2000, Scotland.

The Health and Safety at Work Act, Control of Substances
Hazardous to Health (COSHH).
The Current I.E.E. Wiring Regulations.
Where no specic 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 approved at the time by the Health and Safety

Executive 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.
GB: the following Codes of Practice apply:
BS4814, BS6798, BS5440 Part 1 and 2, BS5546 Part 1,
BS5449, BS6891, BS6700, BS7074 Part 1 and 2, BS7593,
BS7671.

IE: I.S.813, BS5546, BS 5449, BS 7074, BS 7593.
NOTE: For further information, see the current issue of the

Building Regulations, approved document L1 ( in the UK) and
the following current issues of:

1) Central heating system specication (CheSS)
and

2) Controls for domestic central heating system and hot water.
BRECSU.

Gas Supply

The gas installation must be in accordance with the relevant
standards.

In GB, this is BS6891.
In IE, this is the current edition of I.S.813 “Domestic Gas

Installations”.
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 tightness using the
pressure drop method and suitable leak detection uid, purge
in accordance with the above standard.

Domestic Hot Water

All domestic hot water circuits, connections, ttings must be
in accordance with the relevant standards and water supply
regulations.
GB: Guidance G17 to G24 and recommendation R17 to R24
of the Water Regulations Guide.

IE: The current edition of I.S.813 “Domestic Gas Installations”.

Heating System

In GB, it is necessary to comply with the Water Supply (Water

Fittings) Regulations 1999 (for Scotland, the Water Byelaws
2000, Scotland).
To comply with the Water regulations your attention is drawn
to: The Water Regulations guide published by the Water
Regulations Advisory Service (WRAS) gives full details of the
requirements.
In IE, the requirements given in the current edition of I.S.813
“Domestic Gas Installations” and the current Building
Regulations must be followed.

5

Boiler Design

Boiler Design

These boilers are designed to provide central heating from
a fully pumped open vented or sealed water system and
domestic hot water using a fully indirect cylinder.
Once the controls are set the boiler operates automatically.

Range Rating

The boilers are fully modulating for central heating, and it is
therefore not necessary to range rate the boiler. However, if
desired, it is possible to range rate the boiler between 10 and
Max. output (according to the model), in 1kW increments,
refer to section 12.

Safety Devices

Electrical Supply Failure

The boiler will not work without an electrical supply.
Normal operation 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 press the reset
button. If the boiler does not resume normal operation after
this call your Installation/Servicing company or Glow-worm
service.

Overheating Safety

The boiler software is designed to recognise the potential for
an overheat lockout and will shutdown before this happens.
To restart the boiler, press the reset button on the controls
fascia.

If the boiler fails to resume normal operation and all external
controls are calling for heat, then call your Installation/
Servicing company or Glow-worm service.

Condensate Drain

A plastic drain pipe must be tted 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 8 for more details.

Pluming from ue terminal

Like all condensing boilers this appliance will produce a plume
of condensation from the ue terminal in cool weather. This is
due to the high efciency and hence low ue gas temperature
of the boiler. This is normal and not an indication of a fault.

Frost protection

The appliance has a built in frost protection device that
protects the boiler from freezing. With the gas and electric
supplies ON and irrespective of any room thermostat setting,
the frost protection device will operate the pump when the
temperature of the boiler water falls below 8oC.
A timer is used so that the temperature can be checked
periodically. After 10 minutes the pump will be stopped if the
temperature is higher than 10oC or has already reached 35oC.
The burner will activate if the boiler temperature does not
reach 10oC after 30 minutes or at any time if the temperature
drops to 5oC.
The burner will switch off when the temperature reaches 35oC.

Condensate Drain Blockage

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.

Servicing, Maintenance and Spare Parts

Servicing and Maintenance

To ensure the continued efcient and safe operation of the
boiler it is recommended that it is checked and serviced as
necessary at regular intervals. The frequency of servicing will
depend upon the particular installation conditions and usage.
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 approved at the time by the Health and Safety
Executive in accordance with the rules in force in the
countries of destination.
To obtain service, please call your installer or Glow-worm’s
own service organisation using the telephone number on the
inside front cover of this literature.

6

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 specication that we require. Do not
use reconditioned or copy parts that have not been clearly
authorised by Glow-worm.
If a part is required contact Glow-worm’s own service
organisation using the telephone number on the inside front
cover of this booklet.
Please quote the name of the appliance, this infomation will
be on the name badge on the front of the appliance.
If in doubt seek advice from the local gas company or Glow­worm’s own service organisation using the telephone number
on the inside front cover of this booklet.

1 Boiler Specication

BOILER SPECIFICATION

Lift weight 12hx to
Total weight (installed) 12hx to 30hx 28kg (62Ib) 35hx 29.5kg (65Ib)

Gas connection Ø O.D. 15mm. copper

Heating Flow and Return connection Ø O.D. 22mm. copper

Condensate connection Ø I.D. 21.5mm. plastic

Electrical supply 230V~50Hz

Electrical rating 60W fused 3A

IP clasification IPX4D

Internal fuse rating on main PCB 2A

Gas supply (governed meter only) and cat. G20 natural gas

30hx

25kg (55Ib) 35hx 26.5kg (58.4Ib)

14730

Gas Category I

Inlet gas working pressure 20mbar

Burner % CO2 case on 9.3 nominal

Burner % CO2 case off 9.3 nominal

12hx 15hx 18hx 24hx 30hx 35hx

3

/h 1.28 1.60 1.93 2.58 3.26 3.8

Approximate max. gas rate
after 10 mins. from cold

Approximate min. gas rate
after 10 mins. from cold

Approximate gas rate
at part load.

Heat input NETT Q = kW

Heat output P = kW

SEDBUK rating

Flue type (all models) C

m

3

/h 45 56.5 68.1 90.9 115 134

ft

3

/h 0.99 0.99 0.99 0.99 0.99 0.99

m

3

/h 35.1 35.1 35.1 35.1 35.1 35.1

ft

PLEASE REFER TO THE COMMISSIONING SECTION

max. 12.1 15.1 18.2 24.4 30.8 35.8

min. 9.4 9.4 9.4 9.4 9.4 9.4

max. 12 15 18 24 30 35.0

min. 9.3 9.3 9.3 9.3 9.3 9.3

Band A

90.7 90.5 90.4 90.3 90.3 90.0

natural gas

2H

13, C33, C43, C53

NOx (all models) Class 5

Diagram 1.2

7

2 Boiler Dimensions and Hydraulic Schematic

13937

13938

Diagram 2.2

2.1 Boiler Dimensions and Hydraulic Schematic

All dimensions are given in millimetres (except as noted).

The general arrangment of the boiler is shown in diagram 2.1.
and the hydraulic and gas schematic, diagram 2.2.

The data label is positioned on the front of the inner casing
panel.

Diagram 2.1

8

3.1 Location

3 Boiler Location, Clearances and Ventilation

This boiler is not suitable for outdoor installation.
This boiler may be installed in any room, although particular
attention is drawn to the installation of a boiler in a room
containing a bath or shower where reference must be made to
the relevant requirements.
This boiler is suitable for installation in bathroom zones 2 and

3.
In GB this is the current I.E.E. WIRING REGULATIONS and
BUILDING REGULATIONS.
In IE reference should be made to the current edition of I.S.813
“Domestic Gas Installations” and the current ETCI rules.

3.2 Clearances

The boiler should be positioned so that at least the minimum
operational and servicing clearances are provided, see diagram

3.1.
Increased clearances would be benecial for the installation.
Where external access is not practicable, for ue installations
consideration should be given for the space required to insert
the ue internally, which may necessitate the clearance to be
greater than those specied in diagram 3.1.

3.3 Timber Frame Buildings

If the boiler is to be installed in a timber frame building it should
be tted in accordance with the Institute of Gas Engineers
document IGE/UP/7/1998. If in doubt seek advice from the
local gas undertaking or Glow-worm.

12792

3.4 Combustible Material

The boiler and ue are suitable for installation onto and
through combustible materials provided that:-

1) Minimum 5mm clearance is maintained around the
circumference of the ue (air intake).

2) The combustible surface and xings are suitable for
supporting the load.

3) The minimum clearances from the boiler case are
maintained.

3.5 Room Ventilation

The boiler is room sealed so a permanent air vent is not
required.

3.6 Cupboard or Compartment Ventilation

Due to the high efciency and hence low casing temperature
of this boiler, cupboard or compartment ventilation is not
necessary.
Leave existing air vents.

Diagram 3.1

9

4 Flue Options and Terminal Clearances

Ridge Tile Terminal

Part No. A2043800

- Section 10, page 31

Plume Management
Kit basic set, white,

concentric ue
(Ø60/100) - Part No.
A2044100 for use with
Part No. A2043400
and Part No.
A2043600 - Section
10, page 36

Top horizontal telescopic ue (Ø60/100)
Part No. A2043600 - Section 10, page 20

Twin Flue
Twin Flue Adapter, concentric
ue (Ø80) Part No. A2011000

- Section 10, page 32

Top horizontal standard ue (Ø60/100)
Part No. A2043400 - Section 10, page 24

Vertical Flue
Vertical Flue Adapter, concentric
ue (Ø60/100) Part. No. A2024600
Section 10, page 30

Vertical ue terminal kit, concentric
ue (Ø60/100) Part. No.
2000460480 - Section 10, page 30

Direct rear telescopic ue (Ø60/100)
Part No. A2043500 - Section 10,
page 28

10

Multiple Boiler Chimney Flue
Vertical concentric stack ue
suitable for use with:-

Top horizontal telescopic ue,
Top standard horizontal ue,
Twin Flue, as specied by the
manufacturer.

Diagram 4.1

4 Flue Options and Terminal Clearances

HORIZONTAL FLUES

A DIRECTLY BELOW AN OPENING, AIR BRICK,
OPENING WINDOWS 300
B ABOVE AN OPENING, AIR BRICK,
OPENING WINDOWS 300
C HORIZONTALLY TO AN OPENING,
AIR BRICK, OPENING WINDOWS 300
D BELOW GUTTER, DRAIN/SOIL PIPE 25
E BELOW EAVES 25
F BELOW A BALCONY OR CAR PORT 25
G FROM VERTICAL DRAIN PIPES AND
SOIL PIPES 25
H FROM INTERNAL/EXTERNAL CORNERS 25

H* TO A BOUNDARY ALONGSIDE THE
TERMINAL 300
I ABOVE ADJACENT GROUND OR
BALCONY LEVEL 300

J* FROM SURFACE OR A BOUNDARY
FACING THE TERMINAL 600
K FACING TERMINALS 1200
L FROM OPENING (DOOR/WINDOW)
IN CAR PORT INTO DWELLING 1200
M VERTICAL FROM A TERMINAL 1500
N HORIZONTALLY FROM A TERMINAL 300

4.1 Flue Options

There are various ue options to choose from as illustrated in
diagram 4.1. The ue lengths and installation are described in
section 10.

4.2 Flue Terminal Position

In GB the minimum acceptable siting dimensions for the

terminal from obstructions, other terminals and ventilation
openings are shown in diagram 4.2.

In IE the minimum distances for ue terminal positioning must
be those detailed in I.S.813 “Domestic Gas Installations”.

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 ue 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 or more walls, seek
advice from the local gas supply company before installing the
boiler.
NOTE: If the ue terminal is positioned near a light source
insects may enter the ue system. Where safe and practical to
do so advise the homeowner to check the ue outlet and clear
visible insects from the terminal end.

4.3 Terminal Guard

A terminal guard is required if persons could come into contact
with the terminal or the terminal could be subject to damage.
If 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 4.3.
A suitable guard is manufactured by: ­Tower Flue Components
Morley Rd.
Tonbridge
Kent
TN9 1RA.
Size: 280mm x 165mm. Part No. CGDK3

15583

VERTICAL FLUES

P FROM ANOTHER TERMINAL 600
Q ABOVE ROOF LEVEL 300
R FROM ADJACENT OPENING WINDOW 1000
S FROM ADJACENT WALL TO FLUE 300

H* and J* These dimensions comply with the building
regulations, but they may need to be increased to avoid
wall staining and nuisance from pluming depending on site
conditions.

Diagram 4.2

Diagram 4.3

11

Pressure Loss (metres)

5 Water Systems - General

5.1 General

This boiler is designed to provide central heating from a fully
pumped open vented or sealed water system and domestic
hot water using a fully indirect cylinder.

5.2 Draining Points

Draining taps must be provided at all low points of the system,
which will allow the entire system to be drained.
Draining taps shall be to the current issue of BS2879.

5.3 Pump

The pump should be tted on the ow pipe from the boiler and
have isolating valves each side.
A variable duty pump should be set to give a temperature
difference of no greater than 20oC between the ow and
return, with the thermostat set at “MAX”, which is about 80oC,
to give a ow rate as given in the table.
See chart for pressure loss of the boiler, diagram 5.1.
High resistance microbore systems may require a higher duty
pump.

5.4 Flow Rate

If it is necessary to alter the ow rate, the system can be tted
with a lockable balancing valve in the main ow or return
pipes shown in diagram 5.2. The ow rate through the boiler
must not be allowed to fall below that given in diagram 5.1.

5.7 Water Treatment

Existing system- It is ESSENTIAL that prior to installing the

new boiler the system is thoroughly ushed.

New system- For optimum performance after installation, the
boiler and its associated central heating system should also
be ushed.

Flushing should be carried out in accordance with BS7593:
2006 using a cleanser such as Sentinel X300 or X400, Fernox
Restorer or Salamander corrosion guard cleaner.

IMPORTANT: Ensure all cleanser is removed from the whole
system before adding an inhibitor.
For long-term corrosion protection, after ushing, an inhibitor
should be used, refer to the current issue of BS 5449 and
BS 7593 on the use of inhibitors in central heating systems.
Examples are Sentinel X100 Fernox Protector or Salamander
corrosion guard inhibitor.

14401

5.5 Bypass

A system bypass is required and should be tted at least 1.5
metres away from the boiler, refer to the current issue of the
central heating system specications (CHeSS).

5.6 Unvented DHW System

Where a storage system will not have a vent to atmosphere
the installation must comply with the building regulations and

the Water Supply (water ttings) Regulations 1999 and water
byelaws 2000, Scotland, see also the current issue of BS5546

and BS6700.

If tting to an existing system the local authority should be

informed.

General - All domestic hot water circuits, connections, ttings
must be in accordance with the relevant standards and water
supply regulations.

For GB: Guidance G17 to G24 and recommendation R17 to
R24 of the Water Regulations Guide.

For IE: The current edition of I.S.813 “Domestic Gas
Installations”.

35kW

30kW

24kW

15kW

0

5

10

15 20

25

30

Flow Rate (litres/min)

Diagram 5.1

12

5 Water Systems - Open Vented

5.8 Vented (Open) Water System

The boiler must be supplied from an unrestricted water
supply taken from a feed and expansion cistern situated at a
maximum height of 27 metres (90ft) above the boiler.

The cold feed must be 15mm minimum size.

The vent must rise continuously and be unrestricted.

It is important that the relative positions of the pump, cold feed
and open vent are as shown in diagram 5.2.

5.9 Combined Feed and Vent

For combined feed and vent, a 22mm pipe must be tted in
accordance with BS 5449.

5.10 Domestic Hot Water Cylinder

SINGLE FEED INDIRECT CYLINDERS ARE NOT SUITABLE
The domestic hot water cylinder must be of the double feed
fully indirect coil type.

5.11 Draining Points

Draining taps must be provided at the lowest points of the
system, which will allow the entire system to be drained.
A draining point for the appliance is provided at the position
shown in diagram 5.3.

13147

DRAIN
POINT

Diagram 5.2

14506

Diagram 5.3

13

5 Water Systems - Sealed

5.12 Sealed Water Systems

The installation must comply with the appropriate
requirements of the current issue of BS4814, BS5449,
BS6759, BS6798 and BS7074 Part 1 and 2.
See diagram 5.4 for a suggested layout.

5.13 Safety Valve

A safety valve must be tted to a sealed system.
It shall be preset, non-adjustable with a lift pressure of 3 bar,
incorporating seating of a resilient material, a test device and
a connection for drain.
The drain from the safety valve must be routed outside the
building, must not discharge above an entrance or window
or any type of public access area, be clear of any electrical
ttings and positioned so that any discharge can be seen.

5.14 Expansion Vessel

A diaphragm type expansion vessel, conforming to the current
issue of BS4814 (see also BS7074 Part 1 and 2) must be
connected at a point close to the inlet side of the circulating
pump, see the diagrammatic layout, diagram 5.4.
The expansion vessel volume depends on the total water
system volume and the initial system design pressure. For
any system an accurate calculation of vessel size is given in
the current issue of BS5449 and BS7074 Part 1.
Example: For an initial design pressure of 0.7 bar, the mini­mum total vessel volume required is 0.063 x Total System
Volume.
NOTE: A higher initial design pressure requires a larger vol­ume expansion vessel.
Guidance on vessel sizing is also given in the current issue of
BS5449 and BS7074 Part 1, for IE refer to the current edition
of I.S.813 “Domestic Gas Installations”.
The charge pressure must not be less than the static head
of the system, that is, the height of the highest point of the
system above the expansion vessel.

5.15 Pressure Gauge

A pressure gauge with a set pointer and covering at least 0 to
4 bar (0 to 60 lb/in2) shall be tted permanently to the system
in a position where it can be seen when lling the system.

5.16 Domestic Hot Water Cylinder

SINGLE FEED INDIRECT CYLINDERS ARE NOT SUITABLE
The domestic hot water cylinder must be of the double feed
fully indirect coil type. It must be suitable for working at a
gauge pressure of 0.35 bar above the safety valve setting.

Diagram 5.4

14017

14

SUPPLY

5 Water Systems - Sealed

5.17 Water Makeup

Provision should be made for replacing water loss from the
system using a make up bottle mounted in a position higher
than the top point of the system, connected through a non-re­turn valve to the return side of either the heating circuit or the
hot water cylinder.
Alternatively, provision for make up can be made using a
lling loop.

5.18 Filling a Sealed Water System

Provision for lling the system at low level must be made, see
diagram 5.5. There must be no permanent connection to the
mains water supply, even through a non-return valve.

HEATING
CIRCUIT

Method 1

BOILER

RETURNFLOW

CONTROL

VALVE

DRAIN
POINT

HOSE

UNION

11680

PIPE

CONTROL
VALVE

DOUBLE
CHECK
VALVE

HOSE
UNION

TEMPORARY
CONNECTION

HEATING
CIRCUIT

Method 2

BOILER

RETURNFLOW

CONTROL

VALVE

DRAIN
POINT

TYPE CA BACKFLOW

PREVENTION DEVICE

CONTROL

VALVE

AIR GAP

TUNDISH

SUPPLY

PIPE

Diagram 5.5

15

6 Installation Preparation

6.1 Appliance Pack

Please check the contents of packs as shown in diagram 6.1.

The packs are located in the top polystyrene packing.

Remove the carton sleeve and top pack then lift the boiler and
its polystyrene base support out of the lower pack.

6.2 Site Requirements

The boiler mounting wall should be suitable for the weight of
the appliance and be true and at.

NOTE: Due to the varied site conditions we do not supply
xings and advise that the installer should supply those which
are suitable.

6.3 Wall Template

Take the wall template from the document pack located within
the top polystyrene packing and place in the desired position

on the wall, giving due consideration to the required boiler
clearances, see section 3, and the ue you are tting.

Mark the position of the ue centre, if tting a side ue, extend
the ue centre line into the corner then 149mm along the
adjacent wall, see diagram 6.2.

For extended side ues, the ue hole centre should be
determined by extending the dashed inclined line on the
template to the side wall, then 149mm along the adjacent
wall, see diagram 6.2. This dashed line is drawn at 44mm/
metre (2.5°) rise from the boiler.

To allow for the ue passing through the wall at this angle
a 125mm hole should be drilled irrespective of internal or
external installation.

Remove the wall template whilst drilling the ue hole.

BOILER
SECURING
SCREW

Documentation Pack (not illustrated)
Wall Template, User Instructions,
Installation and Servicing Instructions.

Diagram 6.1

14805

14020

6.4 Flue Hole Cutting

External access ue installation can use a 105mm diameter
core drill.

Internal access only ue installation will need a 125mm
diameter core drill.

NOTE: The ue is designed with an internal fall of 44mm/
metre (2.5°), therefore the hole can be drilled horizontally.

If ue extension pipes are to be used then a core drill size of
125mm is required. This will allow the extension pieces to
slope at 44mm/metre (2.5°) towards the boiler.

Diagram 6.2

16

7 Boiler Fixing

7.1 Wall Hanging Bracket

The Wall Hanging Bracket is supplied in the main boiler
packaging.

Reposition the wall template over the ue hole and mark
the position of the xing holes for the hanging bracket, see
diagram 7.1.

NOTE: Due to the varied site conditions we do not supply
xings and advise that the installer should supply those which
are suitable.

Drill xing holes and insert suitable wall plugs.

Direct Rear Flue only - If external access is not available the
ue to be used should be assembled as described in sections

10.11 to 10.13 and inserted through the hole in the wall before
tting the wall hanging bracket.

7.2 Boiler Hanging

IMPORTANT: With regards to the Manual Handling

Operations, 1992 Regulations, the following lift operation
is deemed to be a one man lift, refer to section 17 Manual
Handling.

IMPORTANT: Direct Rear Flue only - The direct rear ue
must be tted before hanging the boiler, refer to sections

10.11 to 10.13, and the rear outlet cover plate should be
removed.

Lifting the boiler into position, lean the top of the boiler slightly
to the wall and position just above the hanging bracket. Lower
the boiler slowly, push back and engage onto the hanging
bracket making sure the boiler is located over the retaining
bosses, secure with screw provided, see diagram 7.2.

14806

Diagram 7.1

14807

SECURING
SCREW

Diagram 7.2

17

8 Gas / Water and Appliance Connection

RETURN

FLOW

22mm compression
is the recommended
fixing for servicing
(not supplied)

VALVE

8.1 Gas Connection

Before connection check the supply of local gas.
The gas supply connection is below the boiler, see diagram

8.1.
The whole of the gas installation, including the meter, should
be inspected, tested for tghtness and purged in accordance
with the current issue of BS6891 and in IE the current edition
of I.S.813 “Domestic Gas Installations”.

PRESSURE
TEST POINT

14507

8.2 Water Connections

Provision is made for the water connections to be made from
above the boiler, see diagram 8.1. The position is shown on
the wall template.
Flush out the domestic hot water and the heating systems
before connecting to the boiler.

12799

GAS SERVICE
ISOLATION

GAS SUPPLY
PIPE IN

Gas Connection

9 Condensate Connections

9.1 Condensate Drain Connection

The condensate drain connection, is positioned below the
boiler as shown in diagram 9.1. To discharge condensate to a
drain, the drain pipe should have a fall of a least 44mm/metre
(2.5°) away 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, refer to diagram 9.2.
It is recommended that any external condensate drain pipe is
protected 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 BS5546 or BS6798 for advice on disposal of boiler
condensate.

WARNING: This appliance must be earthed.

Water Connections

Diagram 8.1

14508

CONDENSATE DRAIN
CONNECTION

Diagram 9.1

18