Saunier duval XEON 40FF User Manual

Instructions for Use

Installation and Servicing

T o be left with the user

40ff

Fanned Flue Boiler

221657C.02.00

7336

(S.I.T.)

This is a Cat II

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.

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.

Thank you for installing a new Saunier Duval appliance in your home.

Saunier Duval appliances' are manufactured to the very highest standard so we are pleased

In the center pages are to be found your Guarantee Registration Card, which we recommend you complete and

If this card is missing you can obtain a copy or record your registration by telephoning the Heatcall Customer

Our Guarantee gives you peace of mind plus valuable protection against breakdown by covering the cost of:

Appliance

2H3P

Guarantee Registration

to offer our customers' a Comprehensive First Year Guarantee.

return as soon as possible.

Service number 01773 828100.

✔

All replacement parts

❏

✔

All labour charges

❏

All call-out charges

✔

❏

One Contact Local Service

REGISTER YOUR SAUNIER DUVAL APPLIANCE

FOR 1ST YEAR GUARANTEE PROTECTION

CALL 0181 380 2555

Customer Services:
Tel: [phone]
Fax: [phone]

Nottingham Road, Belper, Derbyshire. DE56 1JT

Tel: [phone] Fax: [phone]

Hepworth Heating Ltd.,

General/Sales enquiries:

Important Information

Testing and Certification

This boiler is tested and certificated for safety and performance. It is therefore important that no alteration is made to the boiler, without
permission, in writing, from 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, see Section 1.4.

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 Regulatioon 5 certified by: Notified body 0086.
Product/productioncertifiedby: 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 harmonization of the Laws of the Member States relating to the 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.

INFORMATION FOR THE INSTALLER AND SERVICE ENGINEER.

Under Section 6 of The Health and Safety at Work Act 1974, we are required to provide information on substances hazardous to health.

CERAMIC FIBRE/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 of the eyes or severe irritation to the skin seek medical attention.

THERMOSTATS

These contain very small amounts of xylene in the sealed phial and capillary. If broken, under normal circumstances the fluid does not cause a
problem, but in case of skin contact, wash with cold water. If swallowed drink plenty of water and seek medical attention.

CUT-OFF DEVICES

These contain activated charcoal and a very small amount of chlorodifluormethane in the sealed phial and capillary. If broken, under normal
circumstances the fluid does not cause a problem. If there is irritation to the eyes or skin then seek medical attention.

CONTENTS DESCRIPTION SECTION PAGE No.

INSTRUCTIONS

FOR USE

INSTALLATION
INSTRUCTIONS

Introduction 3
Lighting the Boiler 4

General Data 1 5
Flue & Ventilation 2 8
Water Systems 3 9
Flue and Appliance Preparation 4 13
Boiler Installation 5 18
Commissioning 6 22
Instructions to User 7 25

SERVICING

INSTRUCTIONS

221657C

Servicing 8 25
Fault Finding 9 27
Replacement Parts 10 33
Spare Parts 11 38

2

Instructions for Use

Introduction

WARNING. It is important that the case (not the controls tray)
is not disturbed or removed other than for servicing by a
competent person.

Please read these instructions and follow them carefully for the
safe and economical use of your boiler.

The Xeon ff series are fanned flue boilers designed to provide
central heating and indirect domestic hot water.

The boiler is fully automatic in operation having only one user
control, the control thermostat.

Important Notice

If your boiler has been converted to use L.P.G. Propane the
following note applies:

Propane cylinders are under pressure and should never be
stored or used indoors residentially.

They should only be kept outside.
Under no circumstances should L.P.G. Propane cylinders be

fitted or stored in basement areas or boiler houses.

The Gas Safety (Installation and Use)
Regulations

In your interest and that of gas safety it is the law that ALL gas
appliances are installed by a competent person in accordance
with the above regulations.

To obtain service, please call your installer or Heatcall (Saunier
Duval's own Service Organisation) using the telephone number
given on the controls tray.

Please be advised that the ‘Benchmark’ logbook should be
completed by the installation engineer on completion of
commissioning and servicing.

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.

Boiler Clearances

If fixtures are positioned close to the boiler space must be left as
shown in diagram 2. At least a minimum clearance of 500mm
must be left in front of the boiler to allow for servicing.

Boilers Installed in a Compartment or
Cupboard

If the boiler is installed in a compartment or cupboard do not
obstruct any ventilation openings.

Do not use the compartment or cupboard for storage.

CONTROLS COVER

4140

Gas Leak or Fault

If a gas leak or fault exists or is suspected, the boiler must be
turned off, including the electrical supply and must not be used
until the fault has been put right.

Advice/help should be obtained from your installation/servicing
company or the local gas undertaking.

Electrical Supply Failure

Failure of the electrical supply will cause the burner to go out.
Should this occur, operation of the appliance will normally
resume after the electrical supply is restored.

If the boiler does not relight after an electrical supply failure the
overheat safety cutoff device may need resetting, remove the
controls cover and press the reset button, refer to diagram 1.

Overheat Safety Cutoff

If the overheat safety cutoff device operates on any other
occasion than an electrical supply failure, press the reset button
as in “Electrical Supply Failure”. If the overheat operates again,
turn the appliance off and contact your installation/servicing
company.

Maintenance

To ensure the continued efficient 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,
but in general once a year should be enough.

If this appliance is installed in a rented property there is a duty
or care imposed on the owner of the property by the current
issue of The Gas Safety (Installation and Use) Regulations,
Section 35.

It is the law that any servicing is carried out by a competent
person.

VIEWING WINDOW

4625

SETTING POINT

RESET
BUTTON

CONTROL
THERMOSTAT
KNOB

DATA &
SERIAL
NUMBER
LABEL

GAS SERVICE
COCK (Shown
Off)

Diagram 1

3

221657C

Instructions for Use

Cleaning

WARNING. This appliance contains metal parts (components)
and care should be taken when handling and cleaning, with
particular regard to edges.

Clean the casing occasionally by wiping it over with a damp
cloth or dry polishing duster.

Do not use an abrasive cleaner.

Boiler Electrical Supply

WARNING. This boiler must be earthed.
The boiler must only be connected to a 230V~50Hz supply

protected by a 3A fuse.
All wiring must be in accordance with the current issue of

BS7671.
Wiring to the boiler must be PVC insulated type to the current

issue of BS6500 Table 16, not less than 0.75mm
The colours of three core flexible cable are:
Brown - live, Blue - neutral,
Green/yellow - earth.
As the markings on your plug may not correspond with these

colours continue as follows:
The cable coloured blue must be connected to the terminal

marked “N” or black.
The cable coloured brown must be connected to the terminal

marked “L” or red.
The cable coloured green/yellow must be connected to the

terminal marked “E”, or green or the earth symbol

500mm

2

(24/0.20mm).

.

0081N

To Light the Boiler

WARNING. Sealed Systems
A sealed water system must be filled and pressurised by a

competent person.
Only light the boiler when you are sure that the system has been

filled and pressurised.
The pressure gauge should show at least 0.7bar, anything less

than this figure could indicate a leak and you MUST contact your
installation/servicing company.

If there is any doubt about the boiler being full of water consult
your installation/servicing company.

ALL SYSTEMS.
Turn the electrical supply on to the boiler and check that all

remote controls are calling for heat.

To Turn the Boiler On

Remove the controls cover, by withdrawing it forward and off,
see diagram 1.

Turn the control thermostat knob clockwise to any position
between MIN and MAX. The maximum temperature setting is
about 82oC (180oF), see diagram 1.

The boiler lighting operation is now automatic as follows.
The fan operates, followed by an ignition spark until the pilot is

lit. When the pilot is alight the ignition system switches off and
the main burner lights. The flames can be seen through the
viewing window, see diagram 1.

The main burner will remain alight until switched off by the
control thermostat or any remote control.

If the boiler is switched OFF, by hand, wait at least 30 seconds
before switching on again.

When the boiler switches off, both the pilot and main burner go
out.

The automatic lighting sequence will operate again when heat
is required.

Refit the controls cover.

221657C

Additional clearances may be
required for installation

100mm

65mm

FRONT

VIEW

SIDE OR
REAR FLUE
5mm

5mm

6mm6mm

Diagram 2

To Turn the Boiler Off

For short periods, turn the control thermostat knob anti-clockwise
to “O” Off. To relight, turn the control thermostat knob to any
position between “MIN” and “MAX”.

For longer periods, turn the control thermostat knob fully anti­clockwise to “O” Off and switch off the electrical supply to the
boiler.

To relight follow the lighting sequence given above.

Protection Against Freezing.

If the boiler is to be out of use for any long period of time during
severe weather conditions we recommend that the whole of the
system, including the boiler, be drained off to avoid the risk of
freezing up. Make sure that, if fitted, the immersion heater in the
cylinder is switched off.

For the position of the serial number, see diagram 1.

4

1 General Data

B

AP

D

SIDE ELEVATION FRONT ELEVATION

A

70

B

300

6758

FLOW

GRAVITY

RETURN

PUMPED

C

E

WATER CONNECTIONS
22mm COPPER PIPE

GAS CONNECTIONS

1

RC

/2 (1/2 in. BSPT)

GRAVITY

RETURN

PUMPED

FLOW

J

All dimensions are given in millimetres

F

GG

HH

C

L

L

N

D

K

M

(except as noted)

C

63

D

146

E

78

F

360G139

H

87

J

700K574

14

L

M

60

N

130

P

38

Important Notice

This boiler is for use only on natural gas (G20), but may be
converted for use on L.P.G. Propane (G31) with the use of a
conversion kit.

For the 40ff, kit no. 459256
This boiler can be used on open vented or sealed water

systems.
When used on an open vented system domestic hot water can

be provided by gravity or pumped circulation.
Wherever possible, all materials, appliances and components

used shall comply with the requirements of applicable British
Standards.

Where no British Standard exists, materials and equipment
should be fit for their purpose and of suitable quality and
workmanship.

Sheet Metal Parts

WARNING. When installing or servicing this boiler care should
be taken when handling sheet metal parts, to avoid any possibility
of personal injury.

1.1 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:-

The 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 Bye-laws,
The Health and Safety at Work Act, Control of Substances
Hazardous to Health, The Electricity at Work Regulations and
any local regulations which may apply.

Diagram 1.1

Detailed recommendations are contained in the current issue of
the following British Standards and Codes of Practice:-

BS4814, BS6798, BS5440 Part 1 and 2, BS5546 Part 1, BS5449,
BS6891, BS6700, BS7074 Part 1 and 2, BS7593, BS7671.

Manufacturer’s instructions must not be taken as overriding
statutory requirements.

1.2 Data

See Table 1 and diagram 1.1
All dimensions are given in millimetres (except as noted).
The Seasonal Efficiency Domestic Boilers UK (SEDBUK)

is 75.4%.
The value is used in the UK Government’s Standard Assessment

Procedure (SAP) for energy rating of dwellings. The test data
from which it has been calculated have been certified by B.S.I.

1.3 Range Rating

This boiler is range rated and may be adjusted to suit individual
system requirements.

Table 2 gives the ratings and settings.

1.4 Testing and Certification

This boiler is tested and certificated for safety and performance.
It is, therefore, important that no alteration is made to this boiler
unless approved, in writing, by Hepworth Heating Ltd.

Any alteration not approved by Hepworth Heating Ltd., could
invalidate certification, boiler warranty and could also infringe
the statutory requirements.

5

221657C

1 General Data

1.5 Gas Supply

The gas installation shall 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.

DATA TABLE 1.

TOTAL DRY
WEIGHT
(Including

Terminal)
LIFT WEIGHT
WATER

CONTENT

GAS
CONNECTION

ELECTRICITY
RATING

WATER
CONNECTION

ELECTRICITY
SUPPLY

DATA LABEL

Internal fuse Type F1A

4x22mm copper pipes from

230V~50Hz, fused 3A

Bottom right hand side of case

43.4kg
(96lb)

37.7kg
(83lb)

2.35L

0.52gal

1

Rc

/2 in.

56W

top of case

1.6 Electrical Supply

WARNING. This boiler must be earthed.
All system components shall be of an approved type and shall

be connected in accordance with the current issue of BS7671
and any applicable local regulations.

Connection of the boiler and system controls to the mains
supply must be through a common isolator and must be fused
3A, maximum. This method of connection must be by a fused
double pole isolating switch, with a minimum contact separation
of 3mm on both poles. The switch should be readily accessible
and preferably adjacent to the appliance. It should supply the
appliance only and be easily identifiable as so doing.

Alternatively, an unswitched shuttered socket outlet and 3A
fused 3 pin plug, both to the current issue of BS1363 may be
used provided that they are not used in a room containing a bath
or shower.

Wiring to the boiler must be to the current issue of BS6500 Table
16, not less than 0.75mm

6807

2

(24/0.20mm).

1.7 Contents of Packaging

The boiler is delivered in one pack, refer to Section 4.1 for
contents.

1.8 Water System

This boiler may be fitted to an open vented or a sealed water
system.

1.9 Drain

System
A drain tap must be provided at the lowest points of the system

which will allow the entire system, boiler and hot water cylinder
to be drained.

Draining taps should be to the current issue of BS2879.
Boiler
A draining point is fitted at the bottom right hand side of the heat

exchanger.
Cover the controls to avoid water damage.
If required remove the combustion chamber front cover to

improve access.

TABLE 2. 40ff
RANGE RATING
NOMINAL

Min. Medium Max.

kW

11.20

12.93

14.65
HEAT
INPUT(GROSS)

NOMINAL

Btu/h

kW

38,200

8.79

44,100

10.26

50,000

11.72
HEAT
OUTPUT

BURNER

Btu/h

m bar

30,000

8.6

35,000

11.8

40,000

15.0
SETTING
PRESSURE

APPROX.
GAS
RATE

in. w.g.

3

m

/h

3

ft

/h

3.5

1.08

38.2

4.7

1.25

44.1

1.41

50.0

BURNER INJECTOR MARKING: 205708
BURNER INJECTOR SIZE: 2.9
PILOT INJECTOR MARKING: 7218

221657C

6.0

1.10 Safety Valve

7335

A safety valve need not be fitted to an open vented system.

1.11 Location

This boiler is not suitable for outdoor installation.
This boiler may be installed in any room, although particular

attention is drawn to the requirements of the current issue of
BS7671 with respect to the installation of a boiler in a room
containing a bath or shower. Any electrical switch or boiler
control utilising mains electricity should be placed so that it
cannot be touched by a person using the bath or shower. The
electrical provisions of the Building Standards (Scotland) apply
to such installations in Scotland.

The boiler must be mounted on a flat wall which is sufficiently
robust to take its total weight.

The boiler may be fitted to a wall made of combustible material.

6

1 General Data

1.12 Boiler Clearances

Refer to diagram 1.2.
This boiler must be positioned so that at least the minimum

operational and servicing clearances are provided.
Additional clearances may be required for installation.
If fixtures are positioned next to the boiler they should be made

removable for access to pipework.
At least a minimum clearance of 500mm must be left in front of

the boiler for servicing, see diagram 1.2.

500mm

Additional clearances may be
required for installation

0081N

1.13 Room Ventilation

The boiler is room sealed and does not require the room or
space containing it to have permanent air vents.

1.14 Boilers in a Compartment

Where the installation of the boiler will be in an unusual position,
special requirements are needed, the current issue of BS6798
gives detailed guidance on these requirements.

A compartment used to enclose the boiler must be designed
and constructed specifically for this purpose. An existing
cupboard or compartment modified for the purpose may be
used. Details of essential requirements for cupboard or
compartment design are given in the current issue of BS6798.

The doorway opening should be of sufficient size to allow for
easy removal of the boiler.

Where the boiler is fitted in a cupboard or compartment,
permanent high and low level ventilation must be provided. The
minimum ventilation areas required are given in Table 3.

1.15 Timber Frame Building

If the boiler is to be installed in a timber frame 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.

1.16 Heating System Controls

The heating system should have installed: a programmer and
room thermostat controlling the boiler.

Thermostatic radiator valves may be installed in addition to the
room thermostat.

Note: For further information, see The Building Regulations
1991 - Conservation of fuel and power, 1995 edition - Appendix
G, table 4b.

5mm

6mm6mm

SIDE OR
REAR FLUE
5mm

100mm

65mm

FRONT

VIEW

MINIMUM CLEARANCES FROM WALLS,
CEILING, FLOOR, CUPBOARD, WORKTOPS
AND INFLAMMABLE MATERIALS

Diagram 1.2

TABLE 3. COMPARTMENT AIR VENTS

VENTILATION
REQUIREMENTS

VENTILATION
FROM
ROOM
OR SPACE

VENTILATION
FROM
OUTSIDE

HIGH LEVEL
VENT AREA

2

cm

1326620101326620

in

2

LOW LEVEL
VENT AREA

2

cm

in

10

7052

2

7

221657C

2 Flue and Ventilation

Note: Detailed recommendations for flues are given in the
current issue of BS5440 Part 1.

2.1 Terminal Position

The minimum acceptable siting dimensions for the terminal
from obstructions, other terminals and ventilation openings are
shown in diagram 2.1.

The terminal must be exposed to the external air, the position
allowing free passage of air across it at all times.

Car ports 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 it is made of plastic sheeting. If the car port
consists of a roof and two or more walls, seek advice from the
local gas company before installing the boiler.

If the terminal is fitted within 600mm below plastic guttering or
painted soffit an aluminium shield 1500mm long should be fitted
immediately beneath the guttering or eaves. If the terminal is
fitted within 450mm below painted eaves or a painted gutter, an
aluminium shield 750mm long should be fitted immediately
beneath the guttering or eaves.

2.2 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
a minimum of 50mm clearance from any part of the terminal and
be central over the terminal.

A suitable guard, reference Type “K3”, can be obtained from:-

Tower Flue Components Ltd
Morley Road
Tonbridge
Kent. TN9 1RA

D

F

MINIMUM
SPACING

C

K

L

K

G

in mm

L

A

B,C

A

F

G

Under Car Port etc.

G

M

A

E

G

F

G

H,I

MINIMUM SITING DIMENSIONS
FOR FANNED FLUE
TERMINALS POSITION

B,C

K

F

J

K

A DIRECTLY BELOW AN OPENABLE

WINDOW, AIR VENT, OR ANY OTHER

VENTILATION OPENING 300
B BELOW GUTTER, DRAIN/SOIL PIPE 75
C BELOW EAVES 200
D BELOW A BALCONY OR CAR PORT 200
E FROM VERTICAL DRAIN PIPES AND

SOIL PIPES 75
F FROM EXTERNAL CORNERS 300

G ABOVE ADJACENT GROUND OR

BALCONY LEVEL 300

H FROM A SURFACE FACING THE

TERMINAL 600

I FACING TERMINALS 1200

J FROM OPENING (DOOR/WINDOW) IN

CAR PORT INTO DWELLING 1200

K VERTICAL FROM A TERMINAL 1500

L HORIZONTALLY FROM A TERMINAL 300

M FROM INTERNAL CORNERS 25

0103M

221657C

0161M

Diagram 2.1

8

3 Water Systems

The installation of the boiler must comply with the requirements
of the current issue of BS6798.

3.1 Frost Protection

If the position of the boiler is such that it may be vulnerable to
freezing it should be protected as specified in the current issue
of BS5422. It is recommended that a frost protection thermostat
be fitted.

6806

1000

750

500

3.2 Pump

The pump, with integral valves, should be fitted in the heating
flow pipework from the boiler, it should be set to produce a
temperature difference of 11oC (20oF), between the flow and
return, with the boiler thermostat set at “MAX”, which is about
82oC (180oF).

The pressure loss of the boiler can be found from diagram 3.1.
High resistance microbore systems may require a higher duty

pump.

3.3 Bypass - Fully Pumped and Sealed Water
System

A bypass is usually unnecessary on systems using a 3 port
diverter valve since one port will remain in the open position at
all times. This allows satisfactory operation of the pump
overrun.

However if thermostatic radiator valves are fitted to all radiators
or two port valves are used a bypass is required.

The bypass connection must be at least 2 metres away from the
boiler.

The flow through the boiler must not be allowed to fall such that
there is a temperature difference greater than 20
flow and return.

o

C between the

3.4 Water System

For an open vented system the boiler must be supplied from an
unrestricted water supply taken from a feed and expansion
cistern fitted at a maximum height of 27metres above the boiler.

The cold feed must be 15mm minimum size.
It is important that the relative positions of the pump, cold feed

and open vent are as shown in diagram 3.2.
The unrestricted open vent from the boiler must rise continuously

to discharge over the feed and expansion cistern.

3.5 Domestic Hot Water System

General. The domestic hot water service must be in accordance
with the current issue of BS5546, refer also to the current issue
of BS6700.

(mm head of water)

Water pressure loss

250

0

0 5 10 15 20 25 30

Flow rate (litres/minute)

The insertion point indicates the flow rate required to achieve
11°C temperature difference

15.3

Diagram 3.1

3.8 Fully Pumped Heating and Domestic Hot
Water

The connections for this type of system MUST be as shown in
diagram 3.2 and 3.4.

3.9 Inhibitor

Attention is drawn to the current issue of BS5449 and BS7593
on the use of inhibitors in central heating systems.

If an inhibitor is to be used, contact a manufacturer or Hepworth
Heating Ltd., for their recommendations as to the best product
to use.

When installing in an existing system take special care to drain
the entire system, including radiators, then thoroughly cleaning
out before installing the boiler whether or not adding an inhibitor.

3.10 Sealed Water Systems

The installation should comply with the appropriate requirements
of the current issue of BS4814, BS5449, BS6759, BS6798 and
BS7074 Part 1 and 2, see diagram 3.5 for a suggested layout.

3.11 Safety Valve

A safety valve must be fitted to a sealed water system.
It shall be preset, nonadjustable with a lift pressure of 3bar,

incorporating seating of a resilient material, a test device and a
connection for drain.

The drain from the safety valve must be routed clear of any
electrical fittings and positioned so that any discharge can be
seen.

3.6 Cylinder

For all systems supplying domestic hot water the cylinder must
be indirect. It is recommended that the cylinder be fitted with
some form of temperature control.

3.7 Gravity Domestic Hot Water with Pumped
Heating

Important: If domestic hot water is to be provided by a gravity
circulation to the cylinder the blanked off connections must be
opened and used, using 22x28mm connections, see diagram

3.3.

9

221657C

3 Water Systems

OPEN VENTED FULLY PUMPED WATER SYSTEM
RECOMMENDED RELATIONSHIP BETWEEN
PUMP COLD FEED AND VENT

22mm VENT
450mm
MIN.
HEIGHT

FEED AND
EXPANSION
CISTERN

1150mm
MIN.

There must always
be a cold water path
to the return
connection
of the boiler.

BOILER

4124

(MIN.)

15mm (MINIMUM)
COLD FEED

RETURN

PUMP

150mm

FLOW

MAX.

IF REQUIRED
15mm (MINIMUM)
BY-PASS WITH
LOCKSHIELD VALVE

Diagram 3.2

CYLINDER

RET.

6455

FLOW

HEATING

4107

1metre Min.

27 metres

Max.

FLOW

RETURN

22mm
PIPE

22mm VENT & 15mm COLD FEED
TO BE FITTED IN ACCORDANCE
WITH BS 5449

INDIRECT

IF REQUIRED
BYPASS 15mm
MIN WITH
LOCKSHIELD
VALVE

CYLINDER

ALTERNATIVE
SYSTEM
CONTROL
VALVES

PUMP

6461

HEATING
SYSTEM

1m MIN.
27m Max.

VIEWED
FROM
FRONT

28mm

PUMPED

RETURN

PUMPED

22mm VENT

15mm COLD FEED

INDIRECT
CYLINDER
(Shown with
recommended
thermostat and valve).

PUMP

REFER TO BS 5546

FLOW

HEATING
SYSTEM

Diagram 3.3

0090M

FULLY PUMPED CIRCULATION
SYSTEM (DIAGRAMMATIC)

22mm FOR COMBINED FEED & VENT
TO BE FITTED IN ACCORDANCE
WITH BS 5449

INDIRECT
CYLINDER

1metre Min.

27 metres

Max.

FULLY PUMPED CIRCULATION
BYPASS (DIAGRAMMATIC)

IF REQUIRED
BYPASS 15mm
MIN WITH
LOCKSHIELD
VALVE

PUMP

6456

HEATING
SYSTEM

ALTERNATIVE
SYSTEM
CONTROL
VALVES

Diagram 3.4

221657C

10

3 Water Systems

3.12 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 diagram 3.5 unless laid down differently by the
manufacturer.

The expansion vessel volume depends upon the total water
system volume and the initial system design pressure. For any
system an accurate calculation of the vessel size is given in the
current issue of BS7074 Part 1.

Example: For an initial system design pressure of 0.7bar the
minimum total vessel volume required is 0.063xTotal 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.

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.

The water content of the boiler is given in Data Table 1.

3.13 Pressure Gauge

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

3.14 Domestic Hot Water Cylinder

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

It must be suitable for working at a gauge pressure of 0.35bar
above the safety valve setting.

3.15 Domestic Hot Water System - Unvented

Where a storage system will not have a vent to atmosphere the
installation must comply with Building Regulations and local
Water Company Bye-laws, see also the current issue of BS6700.

If fitting into an existing system the local authority must also be
advised.

(Make-up
alternatives)

3 LITRES (0.66 gals)
MAKE-UP BOTTLE
(if required)

NON-RETURN
VALVE

HEATING

CIRCUIT

AUTO
AIR
VENT

FLOW

RETURN

DRAIN
COCK

BOILER

IF REQUIRED
15mm (min)
BY-PASS WITH
LOCKSHIELD
VALVE

SAFETY
VALVE

AIR
RELEASE
POINT

FILLING POINT

CIRCULATING
PUMP

PRESSURE
GAUGE

EXPANSION
VESSEL

6457

11

Diagram 3.5

221657C

3 Water Systems

3.16 Filling a Sealed Water System

Provision for filling the system at low level must be made. Three
methods are shown in diagram 3.6. There must be no permanent
connection to the mains water supply, even through a non­return valve.

3.17 Water Makeup

Provision must be made for replacing water lost from the
system. A make up vessel mounted above the highest point of
the system and connected through a non-return valve to the
system on the return side of either the hot water cylinder or
heating system, see diagram 3.5.

Alternatively provision for make up can be made by a filling loop.

METHOD 1

TEMPORARY
HOSE

SUPPLY
PIPE

METHOD 2

TEMPORARY
HOSE

SUPPLY
PIPE

METHOD 3

CISTERN

HOSE
UNIONS

SUPPLY STOP
VALVE

DOUBLE CHECK
VALVE ASSEMBLY

HOSE
UNIONS

SUPPLY STOP
VALVE

OVERFLOW

SERVICING
VALVE

COMBINED
CHECK VALVE
AND VACUUM
BREAKER

SERVICING
VALVE

SERVICING
VALVE

PRESSURE
REDUCING
VALVE

0051M

HEATING
SYSTEM

HEATING
SYSTEM

HEATING
SYSTEM

SUPPLY
STOP VALVE

SUPPLY
PIPE

HOSE
UNIONS

DOUBLE CHECK
VALVE ASSEMBLY

Diagram 3.6

221657C

12