Hepworth Heating Ltd.,
Nottingham Road, Belper, Derbyshire. DE56 1JT
General/Sales enquiries:
Tel: (01773) 824141 Fax: (01773) 820569
One Contact Total Service
Customer Services:
Tel: (01773) 828100
Fax: (01773) 828070
Installation & Servicing Instructions
220683B.11.96
To be left with the user
70FF 80FF
GC 41 319 86 GC 41 319 60
4098
Fanned Flue Boiler
Reference in these instructions to British Standards Regulations/Requirements apply only to the United Kingdom.
For Ireland the rules in force must be used.
This is a Cat I2H Appliance
BS 6332
BS 5258
2
220683B
SIDE ELEVATION FRONT ELEVATION
B
AP
C
D
E
J
L
M
C
L
D
N
F
G
H
PUMPED
RETURN
PUMPED
FLOW
K
0075(a)M
WATER CONNECTIONS
22mm COPPER PIPE
GAS CONNECTIONS
RC
1
/2 (1/2 in. BSPT)
MODEL A B C D E F G H J K L M N P
80FF 70 300 63 146 78 360 146 94 700 574 14 63 130 38
Diagram 1.1
1 G e n e r a l
The instructions consist of two parts, Installation and
Servicing Instructions and Instructions for Use, 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.
Important Notice
This boiler is for use only on G20 gas.
This boiler can be used on open vented or sealed water
systems.
When used on an open vented system domestic hot water
can only be provided by a pumped circulation.
Wherever possible, all material, appliances and
components used shall comply with requirements of
applicable British Standards.
Where no British Standards exist, 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, Local Water Company Byelaws,
The Health and Safety at Work Act, Control of
Substances Hazardous to Health (COSHH), The
Electricity at Work Regulations and any local
regulations which may apply.
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.
All dimensions are given in millimetres (except as noted)
3
220683B
1.2 Data
See Table 1 and diagram 1.1.
All dimensions are given in millimetres (except as
noted).
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 G e n e r a l
DATA TABLE 1.
MODEL
TOTAL DRY
WEIGHT
(Including
Terminal)
LIFT
WEIGHT
WATER
CONTENT
GAS
CONNECTION
ELECTRICITY
RATING
WATER
CONNECTION
ELECTRICITY
SUPPLY
DATA LABEL
70FF/80FF
51 kg (112 lb)
45.3 kg (100lb)
3.35 litre (0.74 gallon)
Rc 1/2 in.
71W
Internal fuse F1A
2x22mm copper pipes from
top of case
240V~50Hz, fused 3A
Bottom right hand side of case
TABLE 2. 80FF
RANGE RATING
NOMINAL kW
HEAT
INPUT Btu/h
NOMINAL kW
HEAT
OUTPUT Btu/h
BURNER m bar
SETTING
PRESSURE in. w.g.
APPROX. m3/h
GAS
RATE ft3/h
Min. Medium Max.
25.97 27.65 29.31
88,600 94,300 100,000
20.52 21.98 23.45
70,000 75,000 80,000
12.8 14.5 16.3
5.1 5.8 6.5
2.4 2.6 2.7
86 92 97
BURNER INJECTOR MARKING: 205710
BURNER INJECTOR SIZE: 4.0 mm
PILOT INJECTOR MARKING: 7218
TABLE 2. 70FF
RANGE RATING
NOMINAL kW
HEAT
INPUT Btu/h
NOMINAL kW
HEAT
OUTPUT Btu/h
BURNER m bar
SETTING
PRESSURE in. w.g.
APPROX. m3/h
GAS
RATE ft3/h
Min. Medium Max.
22.39 24.03 25.64
76,400 82,000 87,500
17.58 19.05 20.52
60,000 65,000 70,000
13.3 15.3 17.2
5.3 6.1 6.9
2.0 2.2 2.4
74 80 85
BURNER INJECTOR MARKING: 205701
BURNER INJECTOR SIZE: 3.8 mm
PILOT INJECTOR MARKING: 7218
4
220683B
1.4 B.S.I. Certification
This boiler is certificated to the current issue of British
Standard 6332 Part 1, invoking the current issue of
BS5258 Part 1 for performance and safety.
It is, therefore, important that no alteration is made to
this boiler without permission, in writing, from
Hepworth Heating Ltd.
Any alteration that is not approved by Hepworth Heating
Ltd., could invalidate the B.S.I. Certification of the
boiler, warranty and could infringe the current issue of
the Statutory Requirements.
CE Mark
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 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.
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.
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 0.75mm2 (24/0.20mm).
1 General
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 draining tap must be provided at the lowest points of
the system which will allow the entire system, boiler and
hot water cylinder 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 controls to avoid water damage.
If required remove combustion chamber front cover to
improve access.
1.10 Safety Valve
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.
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.
5
220683B
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 of 500mm clearance must be left in
front of the boiler for servicing, see diagram 1.2.
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 a timber frame building it
should be fitted in accordance with the British Gas
publication “Guide for Gas Installation in Timber
Framed Housing”, reference DM2. If in doubt seek
advice from the local gas undertaking or Hepworth
Heating Ltd.
1 General
Diagram 1.2
MINIMUM CLEARANCES FROM WALLS
CEILING, FLOOR, CUPBOARD, WORKTOPS,
AND INFLAMMABLE MATERIALS
500mm
Additional clearances may be
required for installation
65mm
6mm6mm
FRONT
VIEW
100mm
0081M
SIDE OR
REAR FLUE
5mm
5mm
TABLE 3. COMPARTMENT AIR VENTS
VENTILATION HIGH LEVEL LOW LEVEL
REQUIREMENTS VENT AREA VENT AREA
VENTILATION
FROM ROOM
OR SPACE
VENTILATION
FROM
OUTSIDE
MODEL
cm
2
in
2
cm
2
in
2
80FF 264 41 264 41
70FF 231 35 231 35
80FF 264 41 264 41
70FF 231 35 231 35
80FF 132 21 132 21
70FF 116 18 116 18
80FF 132 21 132 21
70FF 116 18 116 18
6
220683B
Note. Detailed recommendations for flue 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
Diagram 2.1
2 F l u e a n d V e n t i l a t i o n
MINIMUM SITING DIMENSIONS
FOR FANNED FLUE
TERMINALS POSITION
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 INTERNAL OR 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
MINIMUM
SPACING
in mm
0103M
A
A
F
G
E
A
G
G
G
B,C
B,C
F
F
K
K
K
C
G
L
L
Under Car Port etc.
H,I
J
D
F
K
0161M
7
220683B
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.
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 MUST be fitted to a fully pumped and sealed
water systems.
Where the water system allows the boiler and pump to
operate on bypass only, the bypass connection must be at
least 2.5metres away from the boiler.
The flow through the boiler must not be allowed to fall
such that there is a temperature difference greater than
20oC between flow and return.
3 W a t e r S y s t e m s
1000
750
500
250
0
0 5 10 15 20 25 30
Flow rate (litres/minute)
Water pressure loss
(mm head of water)
PRESSURE LOSS
OF BOILER 80FF
0088(a)M
30.6
litre/min
Design Flow Rate
The intersection point indicates the Flow Rate
required to achieve 110C temperature difference.
Diagram 3.1
PRESSURE LOSS OF BOILER
30.6
LITRE/MIN
8
220683B
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.
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 Fully Pumped Domestic Hot Water
The connection for this type of system MUST be as
shown in diagram 3.2 and 3.3.
3 W a t e r S y s t e m s
Diagram 3.2
0089M
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
1150mm
MIN.
RETURN
FLOW
CYLINDER
PUMP
HEATING
150mm
MAX.
There must always
be a cold water path
to the return
connection
of the boiler.
BOILER
22mm (MINIMUM)
BY-PASS WITH
LOCKSHIELD VALVE
FLOW
RET.
9
220683B
3.8 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 W a t e r S y s t e m s
Diagram 3.3
FLOW
RETURN
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
BYPASS (DIAGRAMMATIC)
0091(b)M
BYPASS 22mm
MIN WITH
LOCKSHIELD
VALVE
4114
22 x 28
UNION
CONNECTION
28mm
PIPE
10
220683B
3 LITRES (0.66 gals)
MAKE-UP BOTTLE
(if required)
NON-RETURN
VALVE
AUTO
AIR
VENT
FLOW
DRAIN
COCK
BOILER
SAFETY
VALVE
(Make-up
alternatives)
EXPANSION
VESSEL
PRESSURE
GAUGE
CIRCULATING
PUMP
FILLING POINT
AIR
RELEASE
POINT
HEATING
CIRCUIT
22mm (min)
BY-PASS WITH
LOCKSHIELD
VALVE
RETURN
Diagram 3.4
3.9 Sealed Water Systems
The installation should comply with the appropriate
requirements of the current issue of BS4841, BS5449,
BS6759, BS6798 and BS7074 Part 1 and 2, see diagram
3.4 for suggested layout.
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
A diaphragm type expansion vessel, conforming to the
current issue of BS4814 (see also BS7404 Part 1 and 2)
must be connected at a point close to the inlet side of the
circulating pump, see diagram 3.4 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 W a t e r S y s t e m s
5814
11
220683B
3.12 Pressure Gauge
A pressure gauge with a set pointer and covering at least
the range 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
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.
3.14 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.
3.15 Filling a Sealed Water System
Provision for filling the system at low level must be
made. Three methods are shown in diagram 3.5.
There must be no permanent connection to the mains
water supply, even through a non-return valve.
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, see diagram 3.4.
Alternatively provision for make up can be made by a
filling loop.
METHOD 1
METHOD 2
METHOD 3
SUPPLY STOP
VALVE
SUPPLY
PIPE
HOSE
UNIONS
SERVICING
VALVE
TEMPORARY
HOSE
HEATING
SYSTEM
HEATING
SYSTEM
TEMPORARY
HOSE
HOSE
UNIONS
SERVICING
VALVE
SUPPLY
PIPE
SUPPLY STOP
VALVE
DOUBLE CHECK
VALVE ASSEMBLY
HEATING
SYSTEM
SERVICING
VALVE
SUPPLY
STOP VALVE
SUPPLY
PIPE
HOSE
UNIONS
DOUBLE CHECK
VALVE ASSEMBLY
OVERFLOW
CISTERN
COMBINED
CHECK VALVE
AND VACUUM
BREAKER
PRESSURE
REDUCING
VALVE
0051M
Diagram 3.5
3 W a t e r S y s t e m s
12
220683B
Diagram 4.1
Diagram 4.2
Diagram 4.3
Standard Flue terminal illustrated.
Standard Flue terminal illustrated.
4 F l u e a n d A p p l i a n c e P r e p a r a t i o n
REAR FLUE LENGTHS
Distance R = Wall thickness
STD. 75mm to 685mm
1M 75mm to 1015mm
2M 75mm to 2015mm
3M 75mm to 2995mm
SIDE FLUE LENGTHS
Distance S = External wall face to boiler case
STD. 81mm to 693mm
1M 81mm to 1023mm
2M 81mm to 2023mm
3M 81mm to 3003mm
4791
4125
4126
CARTON TOP
WALL
TEMPLATE
LOOSE
ITEMS
PACK
MOUNTING
BRACKET
INSTRUCTIONS
BOILER
4.1 Unpacking
Open the carton, check the items supplied against the
boiler pack contents list on the flap, see diagram 4.1.
4.2 Flue Position and Length
Determine flue application, length and terminal position
before starting.
Refer to diagram 4.2 or 4.3.
If you are using a Flue Bend or a Vertical Flue Kit,
please follow the instructions supplied with that kit.
To make a neat finish to the flue outlet a flue collar kit,
part No. 443286, with instructions, is available.
The use of this collar will mean that the flue lengths will
need to be altered, full instructions are given in the kit.
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