Glowworm Micron 70FF Operating manual

Hepworth Heating Ltd.,
Nottingham Road, Belper, Derbyshire. DE56 1JT
General/Sales enquiries:
Tel: [phone] Fax: [phone]
2000225229A.11.03
All replacement parts
All labour charges
All call-out charges
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 First Year Guarantee.
In the centre pages are to be found your Guarantee Registration Card, which we recommend you complete and
return as soon as possible.
If this card is missing you can obtain a copy or record your registration by telephoning the Heatcall Customer
Service number 01773 828100.
Our Guarantee gives you peace of mind plus valuable protection against breakdown by covering the cost of:
Guarantee Registration
Fanned Flue Boiler
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 current edition of I.S.813
"Domestic Gas Installations" 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.
Tobeleftwiththeuser
7319
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Instructions for Use
Installation and Servicing
G.C. No. 41-047-50
REGISTER YOUR GLOW-WORM APPLIANCE
FOR 1ST YEAR GUARANTEE PROTECTION
CALL 0208 247 9857
70FF
Micron

2
2000225229A
Important Information
Introduction 3
Lighting the Boiler 3
General Data 1 4
Flue and Ventilation 2 7
Water Systems 3 8
Flue and Appliance Preparation 4 10
Boiler Installation 5 13
Commissioning 6 17
Instructions to the User 7 19
Servicing 8 20
Fault Finding 9 21
Replacement of Parts 10 25
Spare Parts 11 28
CONTENTS DESCRIPTION SECTION PAGE No.
INSTRUCTIONS
FOR USE
INSTALLATION
INSTRUCTIONS
SERVICING
INSTRUCTIONS
Testing and Certification
This boiler is tested and certificated to EN483 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.
CE Mark
This boiler meets the requirements of Statutory Instrument No. 3083 The boiler (Efficiency) Regulations, and therefore is deemed
tomeettherequirementsofDirective92/42/EEContheefficiencyrequirementsfornewhotwaterboilersfiredwithliquidorgaseous
fuels.
Type test for purposes of Regulation 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.
Insulation pads and Glass yarn.
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.
SPARE PARTS
REMEMBER, When replacing a part on this appliance, use only spare parts that you can be assured conform to the safety and
performancespecificationthatwerequire. DonotusereconditionedorcopypartsthathavenotbeenclearlyauthorisedbyHepworth
Heating Ltd.

32000225229A
Instructions for Use
Introduction
Pleasereadthese instructions andfollowthem carefully forthe
safe and economical use of your boiler.
The Micron 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 temperature control.
WARNING. It is important that the case is not disturbed or
removed other than for servicing by a competent person.
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/helpshouldbeobtainedfromyour 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, as indicated
by illuminated reset light. Open the controls cover and turn
temperature control to “0” (anticlockwise) and then back to
original position, refer to diagram 9.1.
Note: If the boiler is switched OFF, manually, wait at least 30
seconds before switching on again.
Safety Temperature Limiter
IfthesafetyTemperatureLimiteroperatesonanyotheroccasion
than an electrical supply failure, follow the procedure as in
“ElectricalSupplyFailure”. If the overheatoperatesagain, turn
theapplianceoffandcontactyourinstallation/servicingcompany.
Protection Against Freezing.
In this boiler there is a built-in frost protection, which will cause
theboiler, when it is switchedoff at the control knob,to operate
in the event of the water temperature in the boiler dropping to
6oCor7oC. Theboilerwillswitchoffagainwhenthetemperature
of the water in the boiler reaches about 15oC.
Note:Thefrostprotectionwillnotoperateiftheelectricalsupply
is turned off.
If the boiler is to be out of use for any long period of time during
severeweatherconditionswerecommendthatthewholeofthe
system, including the boiler, be drained off to avoid the risk of
freezingup. Makesurethat,iffitted,theimmersionheaterinthe
cylinder is switched off.
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 in the UK 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.
It is the law that any servicing is carried out by a competent
person.
To obtain service, please call your installer or Heatcall (Glow-
worm’sownServiceOrganisation)usingthetelephonenumber
given on the front cover of these instructions.
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
boilerLogbook. YoucancheckyourinstallerisCORGIregistered
by calling CORGI direct on :- 01256 372300.
Cleaning
WARNING. Thisappliancecontainsmetalparts(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.
To Light the Boiler
WARNING. Sealed Systems
A sealed water system must be filled and pressurised by a
competent person.
Onlylighttheboilerwhenyouaresurethatthesystemhasbeen
filled and pressurised.
Thepressuregauge should showatleast 0.7bar, anythingless
thanthisfigurecouldindicatealeakandyouMUSTcontactyour
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. Check also that the
programmer (if fitted) is in the “ON” mode.
To Turn the Boiler On
Open the controls cover, see diagram 9.1.
Turnthecontrolknobclockwisetoanypositionbetween“O”and
MAX. The maximum temperature setting is approx. 82OC
(180OF), see diagram 9.1.
The boiler lighting operation is now automatic as follows:
The fan will operate for 10 seconds prior to the start of the
ignitionsparks,thegasvalvesolenoidswillopenandtheburner
will light. This is shown by the "Burner Lit" LED on the control
panel lighting up.
The burner will remain alight until switched off by the control
thermostat, any remote control or the programmer.
Note: If the boiler is switched OFF, by hand, wait at least 30
seconds before switching on again.
When the boiler switches off, the boiler will go out.
The automatic lighting sequence will operate again when heat
is required.
Shut the controls cover.
It should be noted that this is a fan flue appliance and fan
operation may be heard.
To Turn the Boiler Off
Forshortperiods,turnthecontrolknobanti-clockwiseto“0”Off.
Torelight,turnthecontrolknobtoany positionbetween“0”and
“MAX”.
For longer periods, turn the control knob fully anti-clockwise to
“0” Off and switch off the electrical supply to the boiler.
To relight follow the lighting sequence given above.
Programmer
An optional programmer is available, which will automatically
switch your central heating system on and off once or twice a
day at whatever times you choose.
Note: If the programmer is manually switched on then off when
the boiler is cold, the boiler may continue to operate for about
30 seconds before switching off.

4
2000225229A
Important Notice
This boiler is for use on natural gas (G20) as distributed in the
United Kingdom and Ireland and cannot be used on any other
gas.
This boiler can be used on open vented or sealed water
systems.
Domestic hot water must be provided by pumped circulation.
Wherever possible, all materials, appliances and components
used shall comply with the requirements of applicable British
Standards.
Where no British Standards exists, materials and equipment
should be fit for their purpose and of suitable quality and
workmanship.
Sheet Metal Parts
WARNING. Wheninstallingorservicingthisboilercareshould
betakenwhenhandlingsheetmetalparts,toavoidanypossibility
of personal injury.
1.1 Statutory Requirements
The appliance is suitable only for installation in GB and IE and
should be installed in accordance with the rules in force.
In GB the installation of the boiler must be carried out by a
competent person 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 BuildingRegulations(Scotland),The Building
Regulations (Northern Ireland).
The Water Fittings Regulations or Water byelaws in Scotland.
The Health and Safety at Work Act, Control of Substances
Hazardous to Health (COSHH).
The Current I.E.E. Wiring Regulations.
Where no specific instructions are given, reference should be
made to the relevant British Standard Code of Practice.
InIE,theinstallationmustbecarriedoutbyacompetentperson
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.
In GB the following Codes of Practice apply:
BS4814,BS6798,BS5440Part1and2,BS5546 Part1,BS5449,
BS6891, BS6700, BS7074 Part 1 and 2, BS7593, BS7671.
In IE: I.S.813, BS5546, BS 5449, BS 7074, BS 7593.
Manufacturer’s instructions must not be taken as overriding
statutory requirements.
1.2 Data
See diagrams 1.1, 1.2 and Table 1.
All dimensions are given in millimetres
The Seasonal Efficiency Domestic Boilers UK (SEDBUK) is
78.2%.
ThevalueisusedintheUKGovernment’sStandardAssessment
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
Thisboileris range ratedandmaybe adjusted tosuitindividual
systemrequirements,refertodiagram1.2fordatalabelposition,
ratings and settings.
1.4 Heating System Controls
The heating system should have installed: a programmer and
room thermostat controlling 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 (in the UK) and
the references:
1)GIL 59, 2000: Central heatingsystem specification (CheSS)
and
2) GPG 302, 2001: Controls for domestic central heating
system and hot water. BRECSU.
Anoptionalprogrammerforfittingontheboilerisavailble,kitno.
458065.
Diagram 1.1
All dimensions are given in millimetres
AB
C
D
E
FG
PUMPED RETURN
PUMPED FLOW
C
WATER CONNECTIONS
22mm COPPER PIPE
GAS CONNECTIONS
RC1/2(1/2in BSPT)
7059
L
H
J
K
E
Installation - 1 General
N
MP
Q
TOP, SIDE
FLUE
OPTION
REAR FLUE
OPTION
MODEL A B C D E F G H J K L M N P Q
70FF 298 75 122 370 146 556 67.5 85 115 128 126 156 100 157 40 92 108
STD/EXD. EASYFIT STD/EXD. EASYFIT

52000225229A
1.5 Gas Supply
The gas installation shall 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 supplyfrom the governed meter must be of adequate size
toprovideasteadyinletworkingpressureof20mbar(8inwg)at
the boiler.
Oncompletiontest the gasinstallationfor soundness usingthe
pressure drop method, purge in accordance with the above
standard.
Diagram 1.2
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.
External wiring must be correctly earthed, polarised and 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".
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
doublepoleisolatingswitch,withaminimumcontactseparation
of3mmonbothpoles. Theswitchshouldbereadilyaccessible
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
usedprovidedthattheyarenotusedinaroomcontainingabath
or shower.
Wiringto the boiler must bePVC 850C insulatedcable, notless
than 0.75mm2(24/0.20mm).
1.7 Contents of Packaging
Theboilerisdeliveredintwoormore packs,dependingon flue
system, refer to diagram 4.1 for contents.
1.8 Water System
This boiler may be fitted to an open vented or a sealed water
system.
1.9 Draining Tap
System
A draining tap must be provided at the lowest points of the
systemwhichwillallowtheentiresystemandhotwatercylinder
to be drained.
Draining taps should be to the current issue of BS2879.
Boiler
Adrainingpointisfittedatthebottomrighthandsideoftheheat
exchanger.
When draining is required, cover the controls to avoid water
damage.
If required remove the combustion chamber front cover to
improve access.
1.10 Safety Valve
A safety valve need not be fitted to an open vented system.
1 General
9444
PMS = 3.0 bar, is: Maximum water-side operating pressure.
The appliance flue type is a C12 and C32. This refers to a concentric
flue where the fan is downstream of the heat exchanger. The C12 is
a horizontal flue termination and the C32 is a vertical flue termination.
7316
DATA
LABEL
TABLE 1.
TOTAL DRY WEIGHT
(Including Terminal)
LIFT WEIGHT
WATER CONTENT
GAS CONNECTION
ELECTRICITY RATING
WATER CONNECTION
ELECTRICITY SUPPLY
DATA LABEL
49.2 kg
40.3 kg
3.35 litre (0.74 gallon)
Rc 1/2in.
81W
Internal fuse Type T3.15A
2x22mm copper pipes from
back of case
230V~50Hz, fused 3A
Top left of inside of case

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2000225229A
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 installation of a boiler in a room
containing a bath or shower where reference must be made to
the relevant requirements.
In GB this is the current I.E.E. WIRING REGULATIONS and
BUILDING REGULATIONS.
InIE reference shouldbe madeto the currentedition of I.S.813
"Domestic Gas Installations" and the current ETCI rules.
Any electrical switch or boiler control utilising mains electricity
shouldbe placedsothatitcannotbetouchedbyapersonusing
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.
Theboilermaybefittedtoawallmadeof combustible material.
1.12 Boiler Clearances
Refer to diagram 1.3.
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 ensure access is
provided for pipework installation.
At least a minimum clearance of 320mm from a permanently
fixed surface must be left in front of the boiler for servicing, see
diagram 1.3.
1.13 Room Ventilation
The boiler is room sealed and does not require the room or
space containing it to have permanent air vents.
FRONT
VIEW
2mm 2mm
*6mm
50mm
MINIMUM CLEARANCES FROM WALLS, CEILING, FLOOR, CUPBOARD,
WORKTOPS AND INFLAMMABLE MATERIALS Diagram 1.3
10mm FROM A NON-PERMANENT
320mm FROM A PERMANENT
6mm 6mm
190mm with Easyfit top flue fitted,
160mm with standard/extended top flue fitted,
20mm without top flue fitted
Increased top clearance is required if flow pipe enters from
below to permit access to air vent.
*
*
1 General
1.14 Boilers in a Compartment
Wheretheinstallationoftheboilerwillbeinanunusualposition,
the current issue of BS6798 gives detailed guidance on these
requirements.
An existingcupboardorcompartmentmodifiedforthepurpose
may be used, providing minimum clearances are maintained.
Detailsofessentialrequirementsforcupboardorcompartment
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 ventilation is not required.
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
documentIGE/UP/7/1998.Ifindoubtseekadvicefromthelocal
gas undertaking or Hepworth Heating Ltd.
1.16 Anti-theft Kits
Anti-theft kits are available for these appliances, contact
Hepworth Heating Ltd. for further information.

72000225229A
The flue must be installed in accordance with the rules in force
in the countries of destination.
2.1 Terminal Position
The minimum acceptable siting dimensions for the terminal
fromobstructions,other terminals andventilation openings are
shown in diagram 2.1. For Ireland the minimum distances for
flue terminal positioning must be those detailed in I.S.813
"Domestic Gas Installations".
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,requirespecialconsiderationwithrespecttoanyopenings,
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
paintedsoffitanaluminiumshield1500mmlongshouldbefitted
immediately beneath the guttering or eaves. If the terminal is
fittedwithin450mmbelowpaintedeavesorapaintedgutter,an
aluminium shield 750mm long should be fitted immediately
beneath the guttering or eaves.
2 Flue andVentilation
2.2 Flue Options
There are various flue systems to choose from, as follows:
Standard Top Outlet Flue Pack - Pt.No. 230483
Easyfit Top Outlet Flue Pack - Pt. No. 232057
Standard Rear Outlet Flue Pack - Pt. No. 230482
Extended Top Outlet Flue Pack - Pt. No. 230487
1 Metre Extension Kit - Pt. No. 230484
A flue system up to 3 metres in length can be made by
connecting 1 metre flue extension kits together.
Optional Wall Liner Kit No. 900862
A Flue Bend Kit or Vertical Flue Kit up to 4 metres can be
supplied, see Hepworth Heating "Flue Options Guide" for
configurations available.
45oFlue Bend Pack - Pt. No. 230485
90oFlue Bend Pack - Pt. No. 230486
In Line Flue Adapter Kit - Pt. No. 230488
Vertical Flue Kit No. 458115
Diagram 2.1
0103M
A
A
FGEA
G
G
G
B,C B,C
FF
K
K
K
C
G
LL
Under Car Port etc.
H,I
JD
F
K
MINIMUM SITING DIMENSIONS FOR
FANNED FLUE TERMINALS POSITION
A DIRECTLY BELOW, ABOVE OR HORIZONTALLY
TO AN OPENING, AIR BRICK, OPENING WINDOWS,
AIR VENT OR ANY OTHER
VENTILATION OPENING. 300
B BELOW GUTTER, DRAIN/SOIL PIPE 25
C BELOW EAVES 25
D BELOW A BALCONY OR CAR PORT 25
E FROM VERTICAL DRAIN PIPES AND SOIL PIPES 25
F FROM EXTERNAL CORNERS 25
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
MINIMUM
SPACING in mm
M

8
2000225229A
7645
FEED AND
EXPANSION
CISTERN
22mm VENT
(MIN.)
15mm (MINIMUM)
COLD FEED
OPEN VENTED FULLY PUMPED WATER SYSTEM
RECOMMENDED RELATIONSHIP BETWEEN
PUMP COLD FEED AND VENT
450mm
MIN.
HEIGHT
1METRE
MIN.
RETURN FLOW
CYLINDER
PUMP
HEATING
150mm
MAX.
BOILER IF REQUIRED
22mm (MINIMUM)
BY-PASS WITH
LOCKSHIELD VALVE
FLOW
RET.
There must always
be a cold water path
to the return
connection
of the boiler.
Diagram 3.1
Diagram 2.2
7056
2.3 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
aminimumof50mmclearancefromanypartoftheterminaland
be central over the terminal, see diagram 2.2.
A suitable guard, reference Type “K3”, can be obtained from:
Tower Flue Components Ltd.,
Morley Road,
Tonbridge,
Kent.
TN9 1RA
2 Flue andVentilation
3Water Systems
Theinstallationoftheboilermustcomplywiththerequirements
of the current issue of BS6798, in Ireland, refer also to the
current edition of I.S.813 “Domestic Gas Installations”.
In GB it is necessary to comply with the Water Supply (Water
Fittings) Regulations 1999 (for Scotland, the Water Byelaws
2000, Scotland).
TocomplywiththeWaterregulationsyourattentionisdrawnto:
TheWaterRegulationsguidepublishedbytheWaterRegulations
AdvisoryService(WRAS)givesfulldetailsoftherequirements.
In IE the requirements given in the current edition of I.S.813
“DomesticGasInstallations”andthecurrentBuildingRegulations
must be followed.
3.1 Frost Protection
Thereisabuilt-infroststatinthisboiler. SeeProtectionAgainst
Freezing in Instructions for Use. Where other parts of the
systemarevulnerablethisshouldalsobeconsideredasspecified
in the current issue of BS5422.
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 at 30.6 litre/minute giving 11oC
temperature difference is 950mm head of water.
High resistance microbore systems may require a higher duty
pump.
3.3 Bypass
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.
Howeverifthermostaticradiatorvalvesarefittedtoallradiators
or two port valves are used a bypass is required.
Thebypassconnectionmustbeatleast2metresawayfromthe
boiler.
Theflowthrough the boilermust not beallowedto fall suchthat
thereisatemperaturedifferencegreaterthan20oCbetweenthe
flow and return.
3.4 Water System
Foranopenventedsystemtheboilermustbesupplied from an
unrestricted water supply taken from a feed and expansion
cisternfittedatamaximumheightof 27metresabovetheboiler.
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 3.1.
Theunrestrictedopenventfromtheboilermustrisecontinuously
to discharge over the feed and expansion cistern.
3.5 Domestic Hot Water System
General - All domestic hot water circuits, connections, fittings
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.
ForIE:ThecurrenteditionofI.S.813“DomesticGasInstallations”.
3.6 Cylinder
Forall systemssupplying domestic hot water thecylinder must
be indirect. It is recommended that the cylinder be fitted with
some form of temperature control.

92000225229A
3Water Systems
3.7 Open Vented Fully Pumped Heating and
Domestic Hot Water
TheconnectionsforthesystemMUSTbeasshownindiagrams
3.1 and 3.2.
Plastic pipes should not be connected directly to the boiler. An
intermediate metallic pipe of 1m in length should be fitted
between the boiler and the plastic pipe system. Plastic pipes
should be type S to BS7291.
3.8 Inhibitor
Attention is drawn to the current issue of BS5449 and BS7593
on the use of inhibitors in central heating systems.
When installing in an existing system take special care to drain
theentiresystem,includingradiators,thenthoroughlycleaning
outbeforeinstallingtheboilerwhetherornotaddinganinhibitor.
3.9 Sealed Water Systems
Theinstallationshouldcomplywiththeappropriaterequirements
ofthe current issue of BS4814,BS5449, BS6759, BS6798 and
BS7074 Part 1 and 2.
3.10 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.
3.11 Expansion Vessel - Sealed Systems only
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, unless laid down differently by the manufacturer.
The expansion vessel volume depends upon the total water
systemvolumeandthe initial system designpressure. Forany
systemanaccuratecalculationofthevesselsizeisgiven 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
BS5449andBS7074Part1, for IE refertothecurrenteditionof
I.S.813 "Domestic Gas Installation".
Thechargepressuremustnotbelessthanthestaticheadofthe
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.
3.12 Pressure Gauge - Sealed Systems only
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.
3.13 Domestic Hot Water Cylinder
SINGLEFEEDINDIRECTCYLINDERSARENOTSUITABLE.
Thedomestichotwatercylindermustbeoftheindirectcoiltype.
It must be suitable for working at a gauge pressure of 0.35bar
above the safety valve setting.
3.14 Domestic Hot Water System - Unvented
Whereastorage system willnothavea vent toatmospherethe
installation must comply with Building Regulations and local
WaterCompanyBye-laws,seealsothecurrentissueofBS6700.
1metre Min.
27 metres
Max.
22mm FOR COMBINED FEED & VENT
TO BE FITTED IN ACCORDANCE WITH BS 5449
INDIRECT
CYLINDER
ALTERNATIVE
SYSTEM
CONTROL
VALVES
HEATING
SYSTEM
PUMP
FULLY PUMPED CIRCULATION BYPASS
(DIAGRAMMATIC)
7152
IF REQUIRED
BYPASS 22mm
MIN WITH
LOCKSHIELD
VALVE
1metre Min.
27 metres
Max.
22mm VENT & 15mm COLD FEED
TO BE FITTED IN ACCORDANCE WITH BS 5449
INDIRECT
CYLINDER ALTERNATIVE
SYSTEM
CONTROL
VALVES
HEATING
SYSTEM
PUMP
FULLY PUMPED CIRCULATION
SYSTEM (DIAGRAMMATIC)
7151
IF REQUIRED
BYPASS 22mm
MIN WITH
LOCKSHIELD
VALVE
Diagram 3.2
PUMPED RETURN
PUMPED FLOW
6770
28mm
PIPE
22mm
PIPE
28mm
PIPE
22mm
PIPE
If fitting into an existing system the local authority must also be
advised.
3.15 Filling a Sealed Water System
Provision for filling the system at low level must be made.
Theinstallationshouldcomplywiththeappropriaterequirements
of the current issue of BS 5449.
3.16 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.

10
2000225229A
4 Flue and Appliance Preparation
TOP OUTLET/REAR FLUE
TOP OUTLET/SIDE FLUE
15mm
VIEW 'B'
510mm
MAX. 15mm
52mm
VIEW 'A'
VIEW 'A'
SPIGOT
FLUE
Note: Outer casing, mounting brackets & boiler details removed for clarity
REAR OUTLET FLUE PACK
EASYFIT/STD./EXTD.TOP OUTLET FLUE PACK
& 1 METRE EXTENSION KIT
SCREW
& TAPE
SCREW
& TAPE
SCREW
& TAPE
FOAM
SEAL
9356
1 metre extension kits
may be joined together,
but the total flue
system must not
exceed 3 metres.
31.5mm*
52mm
FLUE LENGTH
MAX 840mm (extd.)
MAX 570mm (std/Easyfit)
FLUE LENGTH
MAX 840mm (extd.)
MAX 570mm (std/Easyfit)
15mm
SCREW
& TAPE
9.5mm*
144.5mm*
TOP OUTLET FLUE PACK
Note: Outer casing, mounting brackets &
boiler details removed for clarity
Note: Outer casing, mounting brackets & boiler details removed for clarity
'X'
VIEW 'B' 15mm
Total must not exceed 3m MAX.
SCREW
& TAPE
SCREW
& TAPE 'Y'
'X'
'Y' plus 67mm
= FLUE LENGTH
'Y'
'Y'
15mm
52mm
'Y'
SCREW
& TAPE
Total must not exceed 2m MAX.
SCREW
& TAPE
STD.REAR OUTLET FLUE PACK
& 1 METRE EXTENSION KIT
FOAM
SEAL
1 metre extension kits may be
joined together, but the total
flue system must not
exceed 2 metres.
STD/EXTD
'X' plus 24.5mm (RH)
159.5mm (LH) = flue length
STD/EXTD SIDE FLUE
'X' plus 24.5mm (RH)
159.5mm (LH) = flue length
EASYFIT
'X' plus 52.5mm (RH)
'X' plus 187.5mm (LH) = flue length
STD/EXTD REAR FLUE
'Y' plus 35mm = flue length
EASYFIT
'Y' plus 63.5mm = flue length
STD/EXTD
'Y' plus 35mm
= flue length
EASYFIT
'Y' plus 63.5mm
= flue length
EASYFIT
'X' plus 52.5mm (RH)
(must include 50mm min.
side clearance)
'X' plus 187.5mm (LH) = flue length
*STD/EXTD flue only
TOP STD/
EASYFIT
REAR
SIDE R.H.
SIDE L.H.
TOP EXTD.
REAR
SIDE R.H.
SIDE L.H.
REAR STD.
REAR 75 142 510 443 -
MINIMUM
WALL
THICKNESS
MINIMUM
FLUE
LENGTH
MAXIMUM
FLUE
LENGTH
"Y"
BOILER MOUNTING FACE
TO EXTERNALWALL FACE
"X"
BOILER CASINGTO
EXTERNALWALL FACE
MAXIMUM DISTANCE FROM
111
102
237
535
-
-
-
546
411
75
75
75
75
75
75
111
102
237
840
840
840
805
-
-
-
815
680
570
570
570
FLUE
PACKS
NOTE :
IF IT IS NECESSARY TO CUT THE DUCTS
TO ACHIEVETHE "FLUE LENGTH" MAKE SURE
THAT THE OVERLAPS ARE AS FOLLOWS :-
THE OVERLAP FOR AIR DUCT = 25mm
THE OVERLAP FOR FLUE DUCT = 50mm
9357
Diagram 4.1

11 2000225229A
SIDE FLUE
115mm
TOP FLUE OUTLETS
115mm
MINIMUM
HOLES
BOILER
CENTRE LINE
FLUE
CENTRE LINE
BOILER
FIXING POINT
BOILER
FIXING POINT
REAR FLUE
OUTLET
115mm
MINIMUM
HOLE
EASYFIT TOP
FLUE OUTLET
115mm MINIMUM
HOLE
EASYFIT TOP
FLUE OUTLET
115mm MINIMUM
HOLE
NOTE: Makesurethattheductingsdonotslopedowntowards
the boiler.
4.1 Flue Position and Length
Determine flue application, length and terminal position before
starting.
Refer to diagram 4.1.
Ifyouareusing a FlueBendora Vertical FlueKit,pleasefollow
the instructions supplied with the kit.
To make a neat finish to the flue outlet a flue collar kit, part No.
900850, with instructions, is available, see diagram 4.2.
4.2 Flue Preparation
All flue assemblies are designed for internal installation, given
that there is sufficient clearances opposite to the flue for the
installation of the flue.
If there is insufficient clearance the flue can be installed from
outside.
For a wall thickness up to 300mm and provided that there is
sufficient space an optional wall liner kit is available for the flue
to be installed from the inside.
For a wall thickness of over 300mm the external flue hole will
need to be made good from the outside.
This applies also if you use the flue kit without the optional wall
liner kit, irrespective of wall thickness.
4.3 Rear and Side Flue Application
Select the boiler location and flue application, with due regard
to the terminal position, see diagram 2.1.
Takethetemplatefromtheboilerpackandtemporarilyposition
it on the wall, making sure that the minimum clearances are
maintained, see diagram 4.3.
Mark the centre line position of the flue, "Top" or "Rear" as
diagram 4.3.
Forasideflue,extendcentrelineof"Top"toL.H.orR.H.corner.
Mark the position of the centre of the flue and boiler, as
diagram 4.3.
4.4 Flue Hole Cutting
Having marked out the flue centre cut a hole for the flue using,
preferably, a 115mm minimum core drill.
Note: If required an optional wall liner kit, part no. 900862, is
available complete with instructions.
4.5 Wall Mounting Bracket
Repositionthetemplate,makingsureofdimensionalalignment
with the flue hole.
Mark the boiler fixing points and mounting bracket positions,
see diagram 4.4.
Note: The lower mounting bracket is fixed to the boiler.
Drill the holes and insert wall plugs.
Securethetopmountingbracket to the wallwithtwoNo.12x2in
woodscrewsoneoneachsideofthebracket,see diagram 4.4.
Alternativefixingpositionsareprovidedinthebracket,ifrequired.
4.6 Flue Duct
Extend the telescopic flue to the required length, making sure
thattheminimumoverlapisnolessthan25mm,andthattheflue
terminalprojects15mmminmumbeyondwallface,seediagram
4.1.
Carefully drill though air duct pilot hole and secure with self
tapping screw provided in fittings pack, see diagram 4.1.
4 Flue and Appliance Preparation
Diagram 4.3
9351
Diagram 4.4
MOUNTING
BRACKET
SECURING
SCREW
WALL
PLUG
7317
MOUNTING
BRACKET
FIXED TO BOILER
WALL
PLUG
Diagram 4.2
OPTIONAL
FLUE
COLLAR
7148

12
2000225229A
Seal the joint with the tape provided.
If the flue system requires the addition of flue extension kits,
drill,sealandsecurethemwiththe self tapping screw andtape
provided. Thecompletedfluesystemmustnotexceed3metres,
see relevant part of diagram 4.1.
Note: Should any one of the flue sections require cutting to
obtain desired flue system length, cut the 1metre extension kit
at the end opposite the expanded end.
Make sure to cut square and remove any burrs.
Iftheboilerisnottobe fitted for some timecovertheholeinthe
wall.
Note: If a horizontal flue extension is required it must be used
in conjunction with the standard flue, see diagram 4.1.
IMPORTANT: When using the standard flue kit (either rear
outletortop outletfixing)or Easyfit,theterminalrestrictor
must be fitted. This is not fitted for any other flue type/
arrangement, extension kits etc.
Note: There are three restrictors in the loose items pack,
use the one stamped "D" for the Micron 70FF.
Take the terminal restrictor and position the clamping bracket
makingsuretheclampingbracketnibprotrudesintheslotofthe
terminal restrictor and secure with locking screw, but do not
tighten, see diagram 4.6.
Engage the terminal restrictor on the flue terminal by hooking
it over the terminal end and engaging the clamping bracket
behindtheinnerringoftheterminalsecuringitbytighteningthe
locking screw, see diagram 4.6
4.7 Internal Access Flue
Ifaccesstotheoutsidewallisnotpractical,thefluesystemcan
be installed from inside. Use of the optional wall liner kit is
required.
4.8 Rear Flue Fixing
Fittheselfadhesivefoamsealprovidedinthefluepackaround
the air duct at the position shown in diagram 4.1.
Make sure that the ductings do not slope down towards the
boiler.
Make good around the flue outside after installation of boiler.
Important:Ifthewalllinerkitisused,theselfadhesivefoamseal
includedmustbeusedinplaceoftheonesuppliedwiththeflue
pack, see diagram 4.5 for position of self adhesive seal.
4.9 Top, Side Flue Fixing
Make sure that the ductings do not slope down towards the
boiler.
Make good the area around the flue, inside and outside, after
installation of the boiler.
Important:Ifthewalllinerkitisused,theselfadhesivefoamseal
includedmustbeusedinplaceoftheonesuppliedwiththeflue
pack, see diagram 4.5 for position of self adhesive seal.
4.10 Flue Positioning
Pushtheflueassemblyintotheholesuchthatitiswithinthewall
and does not stick out into the room. Do not push the flue
assemblytoofarintotheholeasithastobepulledbackintothe
boiler and secured.
4 Flue and Appliance Preparation
Diagram 4.5
FOAM SEAL
FOAM SEAL
WALL THICKNESS-
OVER 300mm
15mm
WALL THICKNESS-
UP TO 300mm
Q-35mm
Q
Q
7331
Diagram 4.6
7323
RESTRICTOR
CLAMPING
BRACKET
CLAMPING
BRACKET NIB
FLUE
TERMINAL
LOCKING
SCREW
TERMINAL RESTRICTOR
SHOWN FITTED
7332
WITH WALL LINER KIT ONLY
STANDARD 510mm REAR AND
STANDARD 570mm TOP FLUE ONLY
EASYFIT 570mm or less

13 2000225229A
5 Boiler Installation
5.1 Unpacking
Open the carton, check the items supplied against the boiler
pack contents list on the carton flap.
5.2 Boiler Preparation
With the boiler still in the bottom tray, remove the casing front
cover. Open the controls cover first, then by undoing the two
screws at the bottom and the one at the top, lift the front cover
off, see diagram 5.1.
Place front cover in a safe place on one side until required.
Remove boiler.
From the fittings pack, slide a tubing nut and washer on to the
returnand flowtailpipeswhicharesuppliedwiththeboiler,see
diagram 5.2.
Connectthereturnandflowtailpipesto theboiler,seediagram
5.2.
Fit suitable compression fittings to the tail pipes.
For pipework entering the boiler from below, an optional flow
and return pipe incorporating an air vent is available, kit No.
458585, see diagram 5.3.
Note: If the installer wishes to adapt the standard pipework he
maydoso,butmustincorporateanair-ventatthe highest point
on the flow pipe and the highest point of the return pipe, see
diagram 5.11.
5.3 Mounting the Boiler
Ensuretofittheblankingplateandgasketontheboilerflue
outlet not being utilised, see diagram 5.6.
Iftherearflueoutletistobeutilisedfortheinstallationoftheflue,
it will be necessary to connect the flue spigot and gasket to the
outlet using self-tap screws provided, see diagram 5.6.
Note:Thespigotwouldonlybefittedtothetopflueoutletwhere
averticalfluekitorincertainfluebendorientationsisincorporated.
Instructions are supplied with these kits.
Lift the boiler into position, hooking over the top mounting
bracket.
Note: Anti-theft screw kits are are available, part no’s: 458113
and 458114.
Important:Securelowerbrackettowallwithscrewintowall
plug already prepared.
Note:It willbe necessary to move thecontrol boxto access the
bracketby slackening itsretainingscrew andswingingit out on
its hinge, see diagram 5.10.
Wheretheboilerislocatedinarestrictedplace,seediagram1.3
in Instructions for Use, it may be necessary to remove the
control knob to enable the control box to be fully swung out.
If the top flue outlet is to be utilised, secure the top turret and
gasket or flue spigot and gasket depending on desired flue
orientation in position with the 2 taptite and 2 self-tap screws
provided, see diagram 5.9.
Note:Ensurethatthetaptite andself-tapscrewsarepositioned
as shown in diagram 5.8 to enable the air deflector to be fitted
correctly.
Iffixingtothebackoftheboiler,i.e.spigot,slidetheflueinto the
spigotuntil itengages inthe bayonet connection and then twist
clockwise to lock, see diagram 4.1.
Make sure the fitting of the flue to the boiler is correct.
The fan assembly may also be removed or slid forward about
halfway out of the boiler, to ease access.
Disconnectthethe blueandpurpleelectricalconnectionstothe
fan,andthe air pressureswitchtube connections, seediagram
5.5.
Note: Remove the electrical connections by pulling insulation
boots only.
Remove the securing screw at the front, see diagram 5.5.
The fan assembly may now be slid forward. Diagram 5.3
7252
TAIL PIPE
TUBING
NUT
WASHER
AIR VENT
RETURN FLOW
WASHER
Diagram 5.2
Diagram 5.1
CONTROLS COVER
6769
CASE
SECURING
SCREWS
6770
RETURN
TAIL PIPE
TUBING
NUT
RUBBER
WASHER
VIEW ON
COVER TOP
HEATING
FLOW
FLOW
TAIL
PIPE
HEATING
RETURN 28mm
PIPE

14
2000225229A
Rear Flue fixing.
Fitthefanelbowandsecurewithjubileecliptothefanoutlet,do
not tighten yet, see diagram 5.7.
Fit the retaining clamp of the fan elbow, bending the straps
aroundthefanelbowraisedclampingsurfacesbutdonotfasten
the clasp, see diagram 5.7.
It is important that the retaining clamp is fitted the correct way
round, so that the straps locate on to the fan elbow raised
clamping surfaces.
Reconnecttheblueandpurpleelectricalconnectionstothefan,
the polarity of the connections is not important.
Pull the flue duct into the fan elbow to engage.
Important: It is essential to make certain that the flue duct
is fully located into the fan elbow until it can go no further.
Fastenthefanelbowretainingclampclaspthussecuringit,see
diagram 5.7.
Secure the fan elbow to the fan outlet with the Jubilee clip.
Reposition fan assembly.
Top flue fixing
Fitthetwo“O”ringsfromthelooseitemspackontotheflueduct
extension, there are recesses on the flue duct extension for
locating them, see diagram 5.7.
Fit the air deflector in position using the rear left hand taptite
screw and the one diametrically opposite which hold the top
turretandsecurewiththe wing nuts provided,seediagram5.8.
Note: Apply soap to seals on flue duct extension piece to help
it slide on, be careful not to damage ‘O’ ring.
Insertflueductextensionpieceintotopturret,seediagram5.7.
Note:Makesurethattheflueductextensionpieceispositioned
so that the nibs are upper most, see diagram 5.7.
Locate the fan elbow with jubilee clip on the fan outlet, do not
tighten yet, see diagram 5.7.
Reconnecttheblueandpurpleelectricalconnectionstothefan,
the polarity of the connections is not important.
Reposition the fan assembly and draw down the flue duct
extension piece onto the fan elbow, see diagram 5.7.
Fit the retaining clamp of the fan elbow, bending the straps
around the fan elbow raised clamping surfaces and fastening
theclaspthussecuringittotheflueductextension,seediagram
5.7.
It is important that the retaining clamp is fitted the correct way
round, so that the straps locate on to the fan elbow raised
clamping surfaces.
Secure the fan elbow to the fan outlet with the Jubilee clip.
Continued.
Secure the fan assembly by replacing securing screw, see
diagram 5.5.
Reconnect the air pressure switch tubes, ensuring they are in
the correct orientation, as shown in diagram 10.7.
5.4 Water Circulation System
Complete the water connections to the boiler.
Fill, vent and flush the system.
Check for any water leaks and put right.
5.5 Gas Connection
Make the gas connection to the Rc1/2in gas service cock, see
diagram 6.2.
Thewholeofthegasinstallation,includingthemeter,shouldbe
inspected,testedforsoundnessandpurgedinaccordancewith
the current issue of BS6891 and in IE the current edition of
I.S.813 "Domestic Gas Installation".
5 Boiler Installation
ELECTRICAL
CONNECTIONS
7646
RED AIR
PRESSURE
TUBE
SECURING
SCREW
CLEAR AIR
PRESSURE
TUBE
Diagram 5.5
WING
NUT (2)
AIR
DEFLECTOR
Diagram 5.4
MOUNTING
BRACKET
NOTE:
PIPES REMOVED FOR CLARITY
SECURING
SCREW
7107
MOUNTING
BRACKET
NOTE:
REMOVE ELECTRICAL
CONNECTIONS BY GRIPPING
THE BOOT ONLY

15 2000225229A
5 Boiler Installation
5.6 Control Box Access
Slacken the control box securing screw, see diagram 5.10.
Swing the box out on its hinge.
5.7 Electrical Connection
WARNING. This boiler must be earthed.
Note: If an optional programmer is to be installed, it should be
fittedatthisstage,seeseparateinstallationinstructionssupplied
with programmer
Take care not to damage any internal wiring.
Using heat resistant (85oC) cable of at least 0.75mm2 (24/
0.2mm)andofasuitablelength,threadthroughthegrommetat
therearofthecontrolbox,throughthecableclampandconnect
to appropriate terminals. Tighten cable clamp screws, see
diagram 5.10.
Standard colours are, brown - live (L), blue - neutral (N) and
green/yellow - earth ( ).
The mains cable outer insulation must not be cut back external
to the cable clamp.
Make sure the cable is suitably secured.
Whenmakingconnections,makesurethattheearthconductor
ismadeofagreaterlengththanthecurrentcarryingconductors,
so that if the cable is strained the earth conductor would be the
last to become disconnected.
5.8 Pump Connection
Route pump cable as mains, see diagram 5.10.
Connect to control box terminal block, see diagram 9.5.
SPIGOT
Diagram 5.6
BLANKING
PLATE
7150
GASKET
SCREWS
(4)
REAR FLUE
FIXING
TOP FLUE FIXING
SCREWS
(4)
5.9 Testing
Checks to ensure electrical safety must be carried out by a
competent person.
7663
FLUE DUCT
EXTENSION RETAINING
CLAMP
FAN
ELBOW
PRESS
PRESS
PRESS
CLASP
Diagram 5.7
JUBILEE
CLIP
REAR
CONNECTION
(within casing)
FLUE
DUCT
EXTENSION
TOP
CONNECTION
JUBILEE
CLIP
FAN ELBOW
TOP
TURRET
6791
9355
RETAINING
CLAMP
" O " RINGS
FAN ELBOW
CLAMPING
SURFACE NIBS

16
2000225229A
MAINS
NOTE : A SWITCH LIVE (Ls) SHOULD BE CONNECTED
FROM AN EXTERNAL CONTROL.
IF NO EXTERNAL CONTROL IS AVAILABLE INSERTA
LINK BETWEEN Lp & Ls.
SUPPLY
230V ~ 50Hz
L P L S
N P L P N
b
g/y
br
BLOCK
CONNECTOR
TO
PUMP
br bl b y p
Diagram 5.10
SECURING
SCREW
7201
CONTROL BOX
Diagram 5.9
6793
GASKET
SCREWS (4)
TOP TURRET FLUE
OUTLET
FLUE
DUCT
EXTENSION
HINGE PIN
CABLE
CLAMP
TOP
TURRET
After installation of the system, preliminary electrical system
checks as below should be carried out:
1. Test insulation resistance to earth.
2. Test earth continuity and short circuit of all cables.
3. Test the polarity of the mains.
The installer is requested to advise and give guidance to the
user of the controls scheme used with the boiler.
Fit the casing.
5 Boiler Installation
AIR VENT
"T" PIECE
AIR VENT Diagram 5.11
FLOW
RETURN
7334
Diagram 5.8
WING NUT
AIR
DEFLECTOR
7665
TAPTITE
SCREWS
(2)
SELF-TAP
SCREWS
(2)
GROMMET

17 2000225229A
Important Note: The warning notice attached to the
front of the boiler casing must only be removed by
the user.
Please ensure the “Benchmark” logbook is completed and left
with the user.
6.1 All Systems
Commissioningshouldbecarriedoutbyacompetentpersonin
accordance with the current issue of BS6798.
UNDER ALL CIRCUMSTANCES the case must be correctly
fitted and sealed, unless fault finding.
Makesurethatthesystemhasbeenthoroughlyflushedoutwith
cold water without the pump in place.
Refit the pump, fill the system with water, ensuring that all the
air is properly vented from the system and pump.
6.2 Sealed Water Systems Only
Fill until the pressure gauge registers 2.7bar (40lbf/in2). Clear
any air locks and check for water soundness.
Check the operation of the safety valve, by allowing the water
pressure to rise until the valve opens. The valve should open
within +/- 0.3bar (+/- 4.3lbf/in2) of the pre-set pressure. Where
this is not possible conduct a manual check and test.
Note:Fita suitable dischargepipetothe safety valveandroute
it to outside the building so that any discharge can be seen but
will not cause injury to persons, damage to property or any
electrical installation.
Release cold water to initial system design pressure.
Thesetpointeronthepressuregaugeshouldbesettocoincide
with the indicating pointer.
6.3 Initial Lighting and Testing
CAUTION. This work must be carried out by a competent
person, in accordance with the current issue of BS6798.
Make sure that boiler case is fitted securely
Make sure that all naked lights and cigarettes are out.
Open the control cover, refer to the 'Instructions for Use' and
identify the controls, see diagram 9.1.
Remove fascia, see diagram 6.1.
Check that the boiler is isolated from the electrical supply.
Makesure that thetemperature controlis turned tothe “0” “Off”
position, see diagram 9.1.
Undo the screw which holds the control box, refer to diagram
5.10. Swing open control box.
Turn the gas service cock “On”, see diagram 6.2. A 14mm
spanner may be required for this.
Purge in accordance with the current issue of BS6891.
Replace control box.
Turn on the electrical supply.
WARNING. The multifunctional control and fan operate on
mains voltage, terminals will become live.
If programmer control fitted, make sure it is in the ON mode.
Note: If the programmer is manually switched on then off when
the boiler is cold, the boiler may continue to operate for about
30 seconds before switching off.
Make sure that any remote controls are calling for heat.
Turn the temperature control clockwise to “Max”.
The ignition system will operate to light the boiler. After a pre-
set time if ignition has not taken place the boiler will shutdown.
To re-start the lighting sequence, turn the temperature control
to “0”, then fully clockwise to “Max”.
Aftertheburnerhaslit,the“Burneron”neononthecontrolpanel
will come on.
6 Commissioning
Isolate the boiler from the electrical supply.
Loosen the burner pressure test point screw and connect a
suitable pressure gauge, see diagram 6.2.
Replace control box.
Switch on the electrical supply to the boiler.
Diagram 6.1CONTROLS COVER
7318
SECURING
SCREWS
FASCIA
Diagram 6.2
BURNER
PRESSURE
TEST POINT
NOTE: Do not adjust any
other setting screws
7184
GAS
PRESSURE
ADJUSTMENT
SCREW
MULTIFUNCTIONAL
CONTROL
GAS COCK
(ON)
GAS COCK
(OFF)

18
2000225229A
6.4 Testing - Electrical
Turn the boiler temperature control knob fully clockwise to the
maximum setting, which is approx. 82OC (180OF).
The lighting sequence is automatic as follows:
The fan will operate for 10 seconds prior to the start of the
ignitionsparks,thegasvalvesolenoidswillopenandtheburner
will light. This is shown by the "Burner Lit" LED on the control
panel lighting up.
The burner will stay alight until switched off, either by the
temperature control or remote system control. At this point the
fan will overrun by 5 seconds.
To make sure that the flame supervision device is working
correctly the following should be done.
With the burner alight, turn the gas service cock "OFF", see
diagram 6.2.
Afterashortperiodtheburnerwillgooutandfanwilloverrunfor
5 seconds.
Thecorrectworkingoftheflamesupervisiondeviceisshownby
the "Burner Lit" LED going out and the lighting sequence
starting up, as follows:
1. Fan starts.
2. Spark ignition operates for 10 seconds.
3. Fan will overrun for 5 seconds.
4. The fan will start again.
5. After 10 seconds the spark ignition operates, this continues
for a further 10 seconds.
6. Fan will overrun for 5 seconds.
This sequence is repeated ONCE more and the boiler will shut
down. The following illumination will happen with the LED on
the front of the control panel, "Reset" permanently ON and
"Burner Lit" flashing fast (8 Hz).
If the above lighting sequence fails, refer to section 9 - Fault
Finding.
To continue, turn the gas service cock "On", see diagram 6.2.
To restart the lighting sequence, turn the temperature control
knob to "O" then fully clockwise to "Max".
During Normal Operation when the boiler switches "Off", the
burner will go out. The automatic lighting sequence will work
again when heat is required.
6.5 Testing - Gas
With the boiler on proceed as follows:
Undo the screw which secures control box, see diagram 5.10.
Open control box, see diagram 5.10.
WARNING. The multifunctional control and fan operate on
mains voltage, terminals will be live.
Test for gas soundness around the boiler gas components
using a suitable leak detection fluid, in accordance with the
current issue of BS6891.
Check the main burner gas pressure at least 10 minutes after
the boiler has lit, refer to Data Label.
Ifnecessaryremovecapthen adjust the gaspressuretoobtain
the required setting turning screw clockwise to decrease
pressure, see diagram 6.2.
Replace cap.
Shouldanydoubtexistaboutthegasrate,checkitusingthegas
meter test dial and stop watch, at least 10 minutes after the
burnerhaslit,makingsurethatallothergasburningappliances
and pilot lights are off.
6 Commissioning
ThegasratesshowninTable2areforguidanceonly,dependent
on the heat setting.
Turn the temperature control knob fully anticlockwise to “O”.
Isolate from electrical supply.
Removethepressuregaugefromthetestpointandrefitscrew,
making sure a gas tight seal is made.
Refit control box and fascia.
Note: The fixing holes of the fascia are slotted to allow fine
adjustment to align control cover with casing.
When the temperature control is turned to the “O” position, by
hand, wait at least 30 seconds before turning On again.
Theremaybeaninitialsmellgivenofffromtheboilerwhennew,
this is quite normal and it will disappear after a short period of
time.
6.6 Testing - All Water Systems
Allow the system to reach maximum working temperature and
examine for water leaks.
There should be no undue noise in the system.
Theboiler should thenbe turnedoff and thesystem drained off
as rapidly as possible, whilst still hot.
Refill system.
6.7 Open Vented System
Ensure there is no pumping over of water or entry of air at the
open vent above the feed and expansion cistern.
6.8 Adjustment - Fully Pumped Open Vented
and Sealed Water Systems
Whencommissioningthe system theboiler should firstbefired
on full service, that is, central heating and domestic hot water.
Adjust the pump to the system design setting then balance the
system, making adjustments as necessary.
6.9 Thermostatic Radiator Valves
If thermostatic radiator valves are fitted care must be taken to
ensure that there is an adequate flow rate through the boiler
when they close, refer to the current issue of BS7478 for
guidance. If fitted to all radiators ensure a bypass is fitted and
adjusttoachieveatemperaturedifferencenogreaterthan20oC
between flow and return with the thermostatic valves closed.
6.10 Completion
Adjust the boiler temperature control and any system controls
totheirrequiredsettings.Inadditionitisnecessarytocomplete
the "Benchmark" logbook.
ForIE,itisnecessarytocompletea"DeclarationofConformity"
toindicatecompliancetoI.S.813.Anexampleofthisis given in
the current edition of I.S.813.
70FF MIN. MED. MAX.
APPROX. m3/h 2.05 2.21 2.34
GAS RATE ft3/h 72.3 77.9 82.5
Table 2

19 2000225229A
7 Instructions to the User
Instruct and demonstrate the safe and efficient operation of the boiler, heating system and domestic hot water system.
Advisetheuser,thattoensurethecontinuedefficientandsafeoperationoftheboileritisrecommendedthatitischeckedandserviced
at regular intervals. The frequency of servicing will depend upon the particular installation and usage, but in general once a year
should be enough.
Draw attention, if applicable, to the current issue of the Gas Safety (Installation and Use) Regulations, Section 35, which imposes
a duty of care on all persons who let out any property containing a gas appliance in the UK.
The user shall not interfere with or adjust sealed components.
It is the Law that servicing is carried out by a competent person.
Advisetheuser of theprecautionsnecessary to preventdamageto the systemandbuilding in theeventof the heatingsystembeing
out of use during frost and freezing conditions.
Reminder - Leave these instructions and the “Benchmark” logbook with the user.

20
2000225229A
REMEMBER,Whenreplacingapartonthisappliance,useonly
spare parts that you can be assured conform to the safety and
performance specification that we require. Do not use
reconditionedorcopypartsthathavenotbeenclearlyauthorised
by Hepworth Heating Ltd.
Products of Combustion Check
Note: To obtain a products of combustion reading, remove the
capfrom thesampling point, located on top of the inner casing,
see diagram 8.1.
Connect the analyser tube onto the nipple.
Switchontheelectricalsupplyandgassupplythenoperatethe
boiler.
Oncompletionofthetestswitchofftheelectricalsupplyandthe
gas supply, remove analyser tube and replace sampling point
cap.
Servicing
Beforeservicingturnoffthegasandisolatetheelectricalsupply
to the boiler.
Aftercompletingaservicealwaystestforgassoundness,make
electrical checks and carry out functional check on controls.
Unless stated otherwise all parts are replaced in the reverse
order to removal.
8.1 Access
Remove the boiler case, see diagram 5.1 and Section 5.2.
8.2 Burner
Remove front combustion chamber cover which is secured by
two screws, see diagram 10.5.
Remove electrode bracket by undoing screw and withdrawing
off locating pin, see diagram 8.5.
TheHTleadandearthlead(stillconnected)willallowelectrode
to hang down at the front of the appliance.
Removecontrolboxretainingscrew andswingcontrolboxout,
see diagram 5.10.
Remove burner retaining screws, located under boiler casing,
see diagram 8.3.
Pull out burner together with the baffle support, see
diagram 8.3.
To remove baffle support from burner, slide off retaining pins
see diagram 8.3.
Useavacuumcleanerorsuitablestiffbrush tocleantheburner
thoroughly, making sure that all the burner ports are clear and
unobstructed.
On refitting and after cleaning the heat exchanger make sure
the burner is fitted correctly, that is, located on the injector
manifold pins and horizontal, see diagram 8.4.
Note: It is advisable while servicing the burner to check the
combustion insulation and replace if damaged, see Section
10.10.
8.3 Cleaning Heat Exchanger Flueways
Disconnect the air pressure switch tube connections, red from
fan, both clear tubes from test nipple, see diagram 8.1.
Removetheblueandpurpleelectricalconnectionsfromthefan
see diagram 5.5.
Remove the fan assembly complete with the flue elbow, see
diagram 5.5 and Section 5.3.
Place a sheet of paper in the base of the combustion chamber
and over the injectors to prevent particles entering.
Remove the baffles, see diagram 8.2.
Clean the heat exchanger flueways with a suitable stiff brush.
Remove the paper together with any debris.
8 Servicing
Diagram 8.2
BAFFLE
(8 off)
12312
Diagram 8.1
CLEAR AIR
PRESSURE
TUBES
SAMPLING
POINT
RED AIR
PRESSURE
TUBE
7231
Diagram 8.3
ELECTRODE
BRACKET
7173
BAFFLE SUPPORT
BURNER
SCREW BURNER RETAINING
SCREWS
RETAINING PINS
Diagram 8.4
BURNER
INJECTORS
7171
LOCATION
PIN
LOCATION
PIN