Ideal Boilers Classic Combi FF 280 User manual

Classic Combi FF 280
Installation & Servicing
Wall Mounted, Fanned, Balanced Flue Gas Boilers
NOTE TO THE INSTALLER: LEAVE THESE INSTRUCTIONS ADJACENT TO THE GAS METER
Classic Combi G.C. Appliance No.
FF 280 .............................47 415 08
Natural Gas Models Only
CAUTION.
To avoid the possibility of injury during the installation and servicing of this appliance, care should be taken when handling edges of sheet components.

Classic Combi FF 280 - Installation
2
INTRODUCTION
The new Classic Combi FF280 is a cast iron, balanced flue,
fanned gas boiler.
Central heating (CH) output is spot rated at 23.4 kW (80 000
Btu/h) with on/off thermostatic control and is suitable for use with
heating loads down to 4.4 kW (15 000 Btu/h).
Maximum instantaneous domestic hot water (DHW) output is
also 23.4kW (80 000 Btu/h).
The boiler is designed for use with fully pumped sealed water
systems but can also be connected to open water systems if
required.
The boiler casing is of white enamelled mild steel with a
removable controls pod. A drop-down door gives access to the
control box.
Note. This boiler can only be used on fully pumped systems.
The boiler is supplied fully assembled, with a domestic hot water
calorifier, diverter valve, circulating pump, pressure gauge,
safety valve and CH expansion vessel (contained in a module
on top of the boiler).
Fixed temperature CH and DHW controls are fitted and the
boiler incorporates a DHW 'preheat' facility.
The module also includes a CH thermostatic valve and bypass.
No external bypass is required.
The domestic hot water and central heating pipe connections
may be made at the top or bottom of the boiler as required.
The boiler is supplied with a standard flue kit suitable for rear or
side outlet applications up to 600mm (23 1/2"). Optional extra
extension ducts up to 3m (118"), rear or side outlet, are
available.
Note. A Vertex Flue Kit with a side outlet may be used - see the
Vertex Flue Kit Installation Instructions for details.
OPERATION
Domestic Hot Water (DHW)
With no call for either DHW or CH the boiler will periodically fire
at low gas rate for a few seconds, in order to maintain the DHW
calorifier in a preheated condition.
Note. The DHW 'preheat' operates 24 hours a day unless an
external programmer is fitted, when it can be timed.
When there is demand for DHW the boiler fires at full gas rate,
the diverter valve remains de-energised and the full output from
the boiler is directed to the DHW calorifier, providing a maximum
DHW draw-off of 9.6 l/m (2.1 gpm) at 35° C. temperature rise.
At DHW draw-off rates below approximately 6 l/m (1.3 gpm) the
boiler reduces to low gas rate when the DHW temperature
reaches about 60°C and maintains the low draw-off
temperature between 50°C and 75°C. When the demand for
DHW is satisfied the 'preheat' cycle resumes, unless there is a
CH demand, which takes priority.
Central Heating (CH)
When there is demand for CH, the boiler fires at full output, to
supply the demand. The CH circuit within the module
incorporates a thermostatic valve which operates to maintain a
high boiler temperature during periods of cold CH start-up,
necessary for the instantaneous delivery of DHW , if there is a
demand at this time. Water is not released to the system until a
temperature of 60°C. is reached within the boiler.
Refer also to 'Boiler Water Circuit Diagrams'.
GENERAL
CONTENTS
Air Supply ..................................................................... 7
Boiler Clearances ......................................................... 6
Boiler Exploded View ................................................. 46
Burner Exploded View .............................................. .47
Control Box Exploded View ..................................... .47
Electrical Connections .............................................. 25
Electrical Regulations ................................................. 8
Extension Ducts - Fitting ........................................... 21
External Control ......................................................... 27
Fault Finding .............................................................. 48
Flueing .......................................................................... 7
Rear Installation ...................................................... 13
Side Installation ...................................................... 17
Gas Safety (Installation & Use)
Regulations, 1994 ........................................................ 5
Gas Supply ................................................................... 5
Health & Safety Document No 635 ............................. 5
Initial Lighting . .......................................................... 29
Installation .................................................................. 11
Mandatory Requirements ............................................ 5
Pump ........................................................................... 24
Servicing ..................................................................... 32
Short List of Parts ...................................................... 54
Spares Replacement .................................................. 35
Terminal Guards. .......................................................... 7
Thermostatic Radiator Valves. .................................... 8
Water Circuit Diagrams ............................................... 4
Water Connections .................................................... 24
Water Requirements .................................................... 7

Classic Combi FF 280 - Installation 3
Boiler size FF 280
Gas supply connection Rc 1/2 (1/2" BSP/t )
Inlet connection Domestic Hot Water 15mm compression union
Outlet connection Domestic Hot Water 15mm compression union
Flow connection Central Heating 22mm compression union
Return connection Central Heating 22mm compression union
Safety valve drain pipe connection 15mm copper (female)
Flue terminal diameter mm (in.) 100 (4)
Maximum working pressure (sealed systems) bar (psi) 2.5 (36.3)
Maximum static water head m (ft.) 25 (82)
Minimum static water head - open water systems m (ft.) 1.5 (5.0)
Maximum domestic hot water inlet pressure bar (psi) 10.0 (145.0)
Minimum domestic hot water inlet pressure bar (psi) 0.9 (13.1)
Electrical supply 230 V ~ 50 Hz
Maximum power consumption 160W
Fuse rating External; 3A Internal; 2A (F)
Water content Central Heating litre (gal.) 4.65 (1.0)
Domestic Hot Water litre (gal.) 0.55 (0.12)
Dry weight (total) kg (lb) 78.7 (173)
Maximum installation weight kg (lb) Combi module - 11.4 (25.1)
Boiler module - 52.6 (116)
Boiler casing size Height mm (in.) 1045 (41 1/4)
Width mm (in.) 380 (15.0)
Depth mm (in.) Top water connections - 300 (11 3/4)
Bottom water connections - 345 (13 1/2)
Table 1 - General Data
GENERAL
Note. Gas consumption is calculated using a calorific value of 38.7 MJ/m3(1038 Btu/ft3)
Domestic Hot Water Maximum
Burner setting pressure (hot) mbar (in.w.g.) 16.0 (6.4)
DHW output kW (Btu/h) 23.4 (80 000)
DHW input kW (Btu/h) 29.3 (100 000)
Gas consumption (hot) l/s (ft3/h) 0.76 (96.3)
Domestic hot water flow rate at 35°C. temp. rise l/m (gpm) 9.6 (2.1)
Table 3 - Performance Data - Domestic Hot Water
Table 2 - Performance Data - Central Heating
Central Heating Maximum
Burner setting pressure (hot) mbar (in.w.g.) 16.0 (6.4)
Output kW (Btu/h) 23.4 (80 000)
Input kW (Btu/h) 29.3 (100 000)
Gas consumption (hot) l/s (ft3/h) 0.76 (96.3)

Classic Combi FF 280 - Installation
4
1 BOILER WATER CIRCUIT DIAGRAMS
GENERAL

Classic Combi FF 280 - Installation 5
OPTIONAL EXTRA KITS
A Programmer Kit
A 90° Flue Elbow Kit
Extension ducts up to 3 m (118").
GENERAL
GAS SAFETY (INSTALLATION AND USE)
REGULATIONS, 1994.
It is law that all gas appliances are installed by a CORGI
registered installer (identified by ) in accordance with the
above regulations. Failure to install appliances correctly could
lead to prosecution. It is in your own interest, and that of safety,
to ensure the law is complied with.
The installation of the boiler MUST also be in accordance with
the latest I.E.E Wiring Regulations, local building regulations,
bylaws of the local water authority, the Building Regulations and
Building Standards (Scotland) and any relevant requirements of
the local authority.
Detailed recommendations are contained in the following British
Standard Codes of Practice:
BS.6891 Low pressure installation pipes.
BS.6798 Installation of gas fired hot water boilers of rated
input not exceeding 60 kW.
BS.5449 Forced circulation hot water systems.
BS.5546 Installation of gas hot water supplies for domestic
purposes (2nd Family Gases).
BS.5440:1 Flues for gas appliances of rated input not
exceeding 60 kW.
BS.5440:2 Ventilation for gas appliances of rated input not
exceeding 60 kW.
BS.7593:1992 Treatment of water in domestic hot water central
heating systems
HEALTH & SAFETY DOCUMENT NO 635
The Electricity at Work Regulations, 1989.
Manufacturer’s notes must NOT be taken in any way as
overriding statutory obligations.
IMPORTANT.
This appliance is certificated by the British Standards Institution
for safety and performance. It is, therefore, important that no
external control devices, e.g. flue dampers, economisers etc.,
are directly connected to this appliance - unless covered by
these Installation and Servicing Instructions or otherwise
recommended by Caradon Ideal Ltd. in writing.
If in doubt please enquire.
Any direct connection of a control device not approved by
Caradon Ideal Ltd., could invalidate the BSI Certification and
the normal appliance warranty. It could also infringe the Gas
Safety Regulations and the above regulations.
LOCATION OF BOILER
The boiler must be installed on a flat and vertical wall, capable of
adequately supporting the weight of the boiler and any ancillary
equipment.
The boiler may be fitted on a combustible wall. Insulation
between the wall and the boiler is not necessary, unless required
by the local authority. The boiler must not be fitted outside.
Timber Framed Buildings
If the boiler is to be fitted in a timber framed building it should be
fitted in accordance with the British Gas publication 'Guide for
Gas Installations in Timber Frame Housing', reference DM2.
Bathrooms
The boiler may be installed in any room or internal space,
although particular attention is drawn to the requirements of the
current I.E.E. (BS. 7671) Wiring Regulations and, in Scotland,
the electrical provisions of the building regulations applicable in
Scotland with respect to the installation of the boiler in a room or
internal space containing a bath or shower.
Where a room-sealed appliance is installed in a room containing
a bath or shower then the appliance and any electrical switch or
appliance control utilising mains electricity should be so situated
that it cannot be touched by a person using the bath or shower.
Where installation will be in an unusual location special
procedures may be necessary and BS.6798 gives detailed
guidance on this aspect.
Compartment Installations
A compartment used to enclose the boiler should be designed
and constructed specially for this purpose.
An existing cupboard or compartment may be used, provided
that it is modified for the purpose.
In both cases details of essential features of cupboard /
compartment design, including airing cupboard installation, are
to conform to the following:
zBS. 6798.
zThe position selected for installation MUST allow adequate
space for servicing in front of the boiler and for air
circulation around the boiler - see section on 'Air Supply'.
zFor the minimum clearances required for safety and
subsequent service see the wall mounting template and
Frame 2. In addition, sufficient space may be required to
allow lifting access to the wall mounting plate.
GAS SUPPLY
The local gas supplier should be consulted, at the installation
planning stage, in order to establish the availability of an
adequate supply of gas. An existing service pipe must NOT be
used without prior consultation with the local gas supplier.
A gas meter can only be connected by the local gas supplier or
by a local regional contractor.
An existing meter should be checked, preferably by the gas
supplier, to ensure that the meter is adequate to deal with the
rate of gas supply required. A MINIMUM pressure of 20mbar
MUST be available at the boiler inlet, with the boiler operating.
Installation pipes MUST be fitted in accordance with BS. 6891.
Pipework from the meter to the boiler MUST be of an adequate
size.
The complete installation MUST be tested for gas soundness
and purged as described in the above code.

Classic Combi FF 280 - Installation
6
GENERAL
2 BOILER DIMENSIONS / SERVICES
Flue length Accessories Product no.
Up to 600 B pack 1 off 111 492
600 to 1800 B pack 1 off + D pack 1 off 111 492 +
111 493
1800 to 3000 B pack 1 off + D pack 2 off 111 492 +
111 493, 2 off
All dimensions in mm (in.)
It is MOST important that the boiler is installed in a
vertical position.
3 DETERMINING THE FLUE LENGTH
Dimension X: Wall thickness (top water connections)
or
X plus 45mm (bottom water connections)
Dimension Y: Wall thickness plus boiler spacing
IMPORTANT. The direction of the water connections, i.e. to
the top or bottom of the boiler, must be decided BEFORE
determining the flue length and position.
FLUE KITS
Pack B: supplied as standard.
Pack D: optional extension kit for side flue or rear flue outlet.
Refer to 'Flue Extension Ducts'
1. A maximum of 2 extension ducts (plus the standard flue
duct) may be used together.
2. Flue extensions of greater than 1m (39") should be
supported with the bracket provided. If the stand-off
brackets have been used it is necessary, in order to keep
the flue aligned, to use the spacer bracket with the
support bracket.
Dimension Side Flue Rear Flue
A425mm 390mm
B25mm 5mm
flue side both sides
40mm
non-flue side
Additional space will
be required for
installation,
depending upon site
conditions.
Side Flue only
Provided that the flue
hole is cut accurately,
e.g. with a core drill,
The following minimum clearances must be maintained for
operation and servicing (see diagram).
BOILER CLEARANCES
the flue can be installed from inside the building, up to 610mm
(24") but, with flue lengths greater than the width of the boiler, the
space in which the boiler is to be installed must be at least equal
to the flue length plus the length of the terminal grille.
Installation from inside
ONLY
If a core boring tool is to be
used inside the building the
space in which the boiler is
to be installed must be at
least wide enough to
accommodate the tool.
All installations
Once the boiler has been
installed, the side
clearances may be reduced
to 5mm.
Front clearance; 450mm
(17 3/4") from the front of
the boiler casing. Minimum
front clearance when built in
to cupboard is 75mm (3")
2. DHW outlet
3. Safety valve drain
4. CH return
5. CH flow
LEGEND
1. DHW inlet

Classic Combi FF 280 - Installation 7
AIR SUPPLY
Detailed recommendations for air supply are given in
BS.5440:2.
The following notes are for general guidance:
1. It is NOT necessary to have a purpose provided air vent in
the room or internal space in which the boiler is installed.
2. If the boiler is to be installed in a cupboard or compartment,
permanent air vents are required (for cooling purposes) at
both high and low levels. The air vents must either
communicate with room/internal space or be direct to outside
air. The minimum effective areas of the permanent air vents
required in the cupboard/compartment are specified as
follows and are related to maximum rated heat input.
3. Both air vents MUST communicate with the same room or
internal space or MUST be on the same wall to outside air.
4. In siting the air vents care must be taken to avoid the
freezing of pipework.
Refer to Table 5 for details of air vent position and sizing.
GENERAL
FLUE INSTALLATION
The flue must be installed in accordance with the
recommendations of BS. 5440:1.
The following notes are intended for general guidance:
1. The boiler MUST be installed so that the terminal is exposed
to external air.
2. It is important that the position of the terminal allows the free
passage of air across it at all times.
3. Minimum acceptable spacing from the terminal to
obstructions and ventilation openings are specified in
Table 4.
4. Where the lowest part of the terminal is fitted less than 2m
(6'6") above a balcony, above ground or above a flat roof to
which people have access then the terminal MUST be
protected by a purpose designed guard. The minimum
spacing in Table 4; Nos. 2, 3, 4, 5 and 6 would be 75mm in
order to allow a terminal guard to be fitted.
Terminals guards are available from:
Tower Flue Components Ltd.,
Vale Rise, Tonbridge, Kent TN9 1TB
Telephone No. 01732 351 555
Ensure that the guard is fitted centrally.
5. Where the terminal is fitted within 1000mm (39 1/2") of a
plastic or painted gutter or 500mm (19 1/2") of painted
eaves then an aluminium shield at least 1000mm (39 1/2")
long should be fitted to the underside of the gutter or
painted surface.
6. The air inlet/products outlet duct and the terminal of the
boiler MUST NOT be closer than 25mm (1") to combustible
material. Detailed recommendations on the protection of
combustible material are given in BS.5440: Part 1.
7. Where it is essential that the terminal wall plate is fitted, i.e.
wall thicknesses over 600mm (23 5/8") or with an
inaccurately cut hole, the minimum spacing in Table 4, Nos.
2,3, 5 and 6 would be 60mm in order to allow the terminal
wall plate to be fitted.
IMPORTANT
It is absolutely ESSENTIAL to ensure, in practice, that products
of combustion discharging from the terminal cannot re-enter the
building or any other adjacent building through ventilators,
windows, doors, other sources of natural air infiltration or forced
ventilation/air conditioning.
If this should occur, the appliance MUST be turned OFF
immediately, labelled 'unsafe' and corrective action taken.
TERMINAL
The terminal assembly can be adapted to accommodate various
wall thicknesses - refer to Frame 6 'Unpacking'.
Table 4 - Balanced flue terminal position
Terminal Position Minimum Spacing
1. Directly below or alongside an
openable window, air vent or other
ventilation opening 300 mm (12")
2. Below guttering, drain pipes or soil
pipes 25 mm ( 1")
3. Below eaves 25 mm ( 1")
4. Below balconies or a car port roof 25 mm ( 1")
5. From vertical drain pipes or soil pipes 25 mm ( 1")
6. From internal or external corners 25 mm ( 1")
7. Above adjacent ground, roof or
balcony level 300 mm (12")
8. From a surface facing the terminal 600 mm (24")
9. From a terminal facing a terminal 1200 mm (48")
10. From an opening in a car port
(e.g. door or window) into dwelling 1200 mm (48")
11. Vertically from a terminal on the
same wall 1500 mm (60")
12. Horizontally from a terminal on the wall 300 mm (12")
Table 5 - Air supply
Position of air vent Air from room/ Air direct
internal space from outside
High level cm2 (in2) 264 (41) 132 (21)
Low level cm2 (in2) 264 (41) 132 (21)
WATER CIRCULATION SYSTEM
The boiler is designed for connection to sealed water central
heating systems but connection may be made to open water
systems, if required. The domestic hot water (DHW) calorifier is
incorporated within the boiler casing and only requires
connection to the mains water supply.

Classic Combi FF 280 - Installation
8
Water connections maybe made at the top of, or to the bottom
of the boiler.
IMPORTANT
Ensure that the mains water supply pressure is adequate to
provide the required DHW flow rate. Refer to Tables 1 and 3 on
page 3.
The central heating system should be in accordance with BS.
6798 and, in addition, for smallbore and microbore systems,
BS. 5449.
The domestic hot water system should be in accordance with
the relevant recommendations of BS. 5546.
Copper tubing to BS. 2871:1 is recommended for water-
carrying pipework, and MUST be used for pipework carrying
potable water.
Ancillary pipework not forming part of the useful heating surface
should be lagged to prevent heat loss and any possible freezing
- particularly where pipes run through roof spaces and
ventilated underfloor spaces.
IMPORTANT
Draining taps MUST be located in accessible positions, which
permit the draining of the whole system. They should be at least
1/2" BSP nominal size and be in accordance with BS. 2879.
Maximum recommended system hydraulic losses are given in
Table 6 below:
Table 6 - Water flow rate and pressure loss
System load kW 23.4 19.0 4.4
(Btu/h) (80 000) (65 000) (15 000)
Water flow rate l/min 22.5 24.8 5
(gal/h) (297) (327) (75)
Temperature °C 15 11 11
differential (°F) (27) (20) (20)
Pressure mbar 157 118 391
available for system (in. w.g.) (63) (47) (157)
GENERAL
THERMOSTATIC RADIATOR VALVES
Caradon Ideal Ltd. recommend that heating systems utilising
full thermostatic radiator valve control of temperature in
individual rooms should also be fitted with a room thermostat
controlling the temperature in a space served by radiators not
fitted with such a valve, as stated in BS. 5449.
When thermostatic radiator valves are used the space heating
temperature control over a living / dining area or hallway having
a heating requirement of at least 10% of the boiler heat output
should be achieved using a room thermostat, whilst other rooms
are individually controlled by thermostatic radiator valves.
However, if the system employs thermostatic radiator valves on
all radiators or 2 port valves without end switches then a bypass
must be fitted to ensure a flow of water, should all valves be in
the closed position.
ELECTRICAL SUPPLY
Wiring external to the appliance MUST be in accordance with
the current I.E.E. (BS.7671) Wiring Regulations and any local
regulations which apply.
The point of connection to the mains should be readily
accessible and adjacent to the boiler, except that for bathroom
installations; the point of connection to the mains MUST be
situated outside of the bathroom.
Note. Where a room sealed appliance is installed in a room
containing a bath or shower then the appliance and any
electrical switch or appliance control utilising mains electricity
should be so situated that it cannot be touched by a person
using the bath or shower.

Classic Combi FF 280 - Installation 9
Safety valve setting bar 3.0
Vessel charge pressure bar 0.5 to 0.75
System pre-charge pressure bar None 1.0
System volume (litres) Expansion vessel
volume (litres)
25 1.6 1.8
50 3.1 3.7
75 4.7 5.5
100 6.3 7.4
125 7.8 9.2
150 9.4 11.0
175 10.9 12.9
190 11.9 14.0
200 12.5 14.7
250 15.6 18.4
300 18.8 22.1
Multiplying factors for
other system volumes 0.063 0.074
4 SYSTEM REQUIREMENTS - CENTRAL HEATING
Mains water
supply
Boiler
3. Mains Connection
There must be no direct connection to the mains water supply
or to the water storage tank supplying domestic water, even
through a non-return valve, without the approval of the local
water authority.
4. Filling
The system may be filled by one of the following methods:
a. Through a temporary hose connection from a draw-off tap
supplied from a service pipe under mains pressure. Where
the mains pressure is excessive a pressure reducing valve
must be used to facilitate filling.
i. Thoroughly flush out the whole system with cold
water.
ii. Fill and vent the system until the pressure gauge
registers 1.5 bar (21.5 psi) and examine for leaks.
iii. Check the operation of the safety valve by raising the
water pressure until the valve lifts. This should occur
within 0.3 bar (4.3psi) of the pre-set lift pressure.
iv. Release water from the system until the minimum
system design pressure is reached - 1.0bar (14.5 psi)
if the system is to be pre-pressurised.
CH RETURN CH FLOW
stop valve
test cock
Double check valve
Hosepipe
(disconnect
after filling)
Hose
union bib
tap
Notes.
a. The method of filling, refilling, topping up or flushing sealed
primary hot water circuits from the mains via a temporary hose
connection is only allowed if acceptable to the local water
authority.
b. Antifreeze fluid, corrosion and scale inhibitor fluids suitable for use
with boilers having cast iron heat exchangers may be used in the
central heating system. For further information contact:
Fernox Manufacturing Co. Ltd.,
Britannic Works, Clavering, Essex. CB11 4QZ.
Tel: [phone]
or
Grace Service Chemicals
Grace Dearborn Ltd.,
Widnes, Cheshire. WA8 8UD.
Tel: [phone]
1. General
a. The installation must comply with the requirements of
BS.6891:1988 and BS.5449:1.
b. The installation should be designed to work with flow
temperatures of up to 820C.
c. All components of the system must be suitable for a
working pressure of 3 bar (45psi ) and temperature of
1100C. Care should be taken in making all connections so
that the risk of leakage is minimised.
The following components are incorporated within the
appliance:
• Circulating pump
• Safety valve, with a non-adjustable pre-set lift
pressure of 3bar (45 psi)
• Pressure gauge, covering a range of 0-6 bar.
• 8-litre expansion vessel, with an initial charge
pressure of 0.75 bar.
For further details refer to BS. 5449:1 and British Gas
publication 'Specifications for Domestic Central Heating and
Hot Water'.
2. Make-up Water
Provision must be made for replacing water loss
from the system, either:
a. From a manually filled 'make-up' vessel with a
readily visible water level.
The vessel should be mounted at least 150mm (6")
above the highest point of the system, and be
connected through a non-return valve to the
system, fitted at least 150mm (6") below the
make-up vessel on the return side of the domestic
hot water cylinder or radiators.
b. Where access to a make-up vessel would be
difficult by pre-pressurisation of the system.
Refer to note 4 'Filling'. The maximum cold water
capacity of the system should not exceed 127
litres if not pressurized. However, if the system is
to be pressurized the efficiency of the expansion
vessel will be reduced and a larger vessel (or
smaller system volume) may be necessary. If the
capacity of the vessel is not considered sufficient
for this, or for any other reason, an additional
vessel MUST be installed on the return to the
boiler. Guidance on vessel sizing is given in the
table shown and also in BS.7074:1 and
BS.5449:1.

Classic Combi FF 280 - Installation
10
5 SYSTEM REQUIREMENTS - CENTRAL HEATING - continued
The following fittings shall form a permanent part of the
system and shall be fitted in the order stated:
• A stop valve complying with the requirements of
BS. 1010:2 (the hose from the draw-off tap shall be
connected to this fitting).
• A test cock.
• A double check valve of an approved type.
GENERAL
Boiler
Cistern
Mains
water
supply
b. Through a cistern, used for no other purposes, via a ball
valve permanently connected directly to a service pipe
and/or a cold water distributing pipe.
The static head available from the cistern should be
adequate to provide the desired initial system design
pressure.
Note. The stop valve may remain open during normal
operation of the system if automatic water make-up is
required.
5. The maximum recommended system hydraulic losses are
given below:
System load kW 23.4 19.0 4.4
(Btu/h) (80 000) (65 000) (15 000)
Water flow rate l/min 22.5 24.8 5.7
(gal/h) (297) (327) (75)
Temperature °C 15 11 11
differential (°F) (27) (20) (20)
Pressure mbar 157 118 391
available for system (in. w.g.) (63) (47) (157)
6. Thermostatic radiator valves
Caradon Ideal Ltd., support the recommendations made
by leading manufacturers of domestic heating controls that
heating systems utilising full thermostatic radiator valve
control of temperature in individual rooms should also be
fitted with a room thermostat controlling the temperature in
a space served by radiators not fitted with such a valve.
Such an arrangement will provide for a more efficient
control of the environment and will also avoid the
continuous running of the circulation pump during
programmed heating ON periods, saving electrical energy.
It is therefore strongly recommended that, when
thermostatic radiator valves are used, the space heating
temperature control over a living / dining area or a hallway
having a heating requirement of at least 10% of the boiler
output is achieved using a room thermostat, whilst other
rooms are individually controlled by thermostatic radiator
valves.
7. Open vented systems
The Classic Combi FF280 is designed for use with sealed
systems but can also be connected to open vented
systems if required.
Note. To comply with the relevant requirements of
BS.5449:1 and BS.6798 the positions of the cold feed and
vent must be as shown.
DOMESTIC HOT WATER REQUIREMENTS
The Classic Combi FF280 is suitable for connection to most
types of washing machine and dish washing appliances.
When connecting to suitable showers ensure that:
• The cold inlet to the boiler is fitted with an approved anti-
vacuum or syphon non-return valve.
• Hot and cold water supplies to the shower are of equal
pressure.
IMPORTANT.
Provision must be made to accommodate the expansion of
DHW contained within the appliance if a non-return valve is
fitted to the DHW inlet. Refer to Frame 4.
22mm open vent
Water level
450mm (min.)
450mm (min.) above
highest point in the
system
150mm
(max.)
Boiler
Inverted cold feed
connection - 15mm
Heating
load
1500mm
(min.)
CH RETURN CH
FLOW
Non-return valve
Automatic
air vent
stop valve

Classic Combi FF 280 - Installation 11
Pack A Contents
zCombi module
zBoiler
zPack A1
INSTALLATION
The appliance is supplied as 2 separate modules (i.e. boiler module and Combi module) together with wall mounting plate
(Pack A1) in one Pack A.
Also supplied is a standard flue assembly for lengths up to 600mm (23 1/2"), rear or side flue outlet, in Pack B.
Optional extras, if ordered (Extension Duct Kit D, Vertex Flue Kit G, Roof Flue Kit H and 90° Flue Elbow Kit) are available in
separate boxes.
Unpack and check the contents.
6 UNPACKING
Pack B Contents:
zFlue cutting support (cardboard) - 1 off
zTerminal wall plate - 1 off
zTerminal grille assembly - 1 off
zPolyurethane foam seal 400 lg - 1 off
zNo. 8 x 8 lg. Pozi pan screw hd. screws - 3 off
Pack A1 Contents
(contained within Pack A)
zInstallation & Servicing Instructions
zUser's Instructions
zHardware Pack (listed below)
zWall mounting template
zWall mounting plate
zStand-off brackets - 2 off
zSide outlet terminal mounting plate
Hardware Pack Contents
zNo.14 x 50mm wood screws - 8 off
(for wall mounting plate)
zNo.10 x 50mm wood screws - 8 off
(for side outlet plate and terminal
wall plate)
zWall plugs - 16 off
zM6 nuts - 8 off
(for stand-off brackets)
zM6 screws - 8 off
(for stand-off brackets)
zM6 washers - 8 off
(for stand-off brackets)
zSealing plate - 1 off
(for back panel)
zM8 x 12mm screw - 1 off
(for sealing plate)
zM8 washer - 1 off
(for sealing plate)
z22mm compression elbow - 1 off
(for boiler / combi RETURN)
z22mm brass elbow - 1 off
(for boiler / combi FLOW)
zPlastic elbow extractor - 1 off
z7/8" sealing washers - 2 off
(for CH flow and return)
z3/4" sealing washer - 1 off
z1/2" sealing washers - 3 off
(for DHW inlet & outlet and
CH expansion vessel)
z2 1/2" pozi-screw - 1 off
(for Combi module cover)
zRubber gasket and screw - 1 off
(bypass valve)
zTerminal strip cover - 1 off
zM5 washer - 1 off
zM5 extended nut - 1 off
zFlue extension tube - 1 off
zM5 wing nut - 3 off
zIEC mains plug
zBoiler sealing plate
INSTALLATION
Flue terminal Terminal wall plate

Classic Combi FF 280 - Installation
12
INSTALLATION
7 PACKAGING AND CASING REMOVAL
INSTALLATION
1. Unpack the boiler.
2. Remove the casing as follows and place to one side to
avoid damage:
a. Release controls pod fixing screws (a) 3 full turns only.
Remove the pod by pulling it forward to disengage from
the keyhole slots.
b. Undo the 4 screws (b) retaining the
casing to the back panel.
c. Remove the casing in the direction of the
arrows.
3. Remove the boiler from its packaging base.
The boiler may now be stood upright on its
controls support protection frame to ease
handling and installation.
4. Unpack the flue assembly / extension flue
box(es).
(a) Controls pod
fixing screws, 2 off
(b) Casing retaining
screws, 4 off
Packing base
Controls pod casing

Classic Combi FF 280 - Installation 13
Note. If the
terminal is to be
sited within 25-
40mm of a corner
or vertical pipe
(refer to Table 4)
then the hole
MUST be
accurately cut and
the rubber
weather seal
trimmed around
the groove
provided.
The terminal wall
plate need not be
fitted.
INSTALLATION REAR FLUE OUTLET ONLY
8 FLUE ASSEMBLY - Exploded View
10 PREPARING THE WALL
IMPORTANT.
Ensure that, during the cutting operation, masonry falling outside
of the building does not cause damage or personal injury.
1. Cut the flue hole preferably with a 125mm (5") core boring
tool, ensuring that the hole is square to the wall. If the hole
has been quite accurately cut with a drill, then making good
the wall faces is not essential as seals are provided at both
ends of the flue. However, both wall faces immediately around
the cut hole should be flat; make good if necessary. For less
accurate holes make good to approximately 125mm (5")
diameter at the 2 wall faces.
2. Drill 9 holes for the wall mounting plate with an 8mm (5/16")
masonry drill.
3. Insert the plastic plugs provided.
1. An optional flue
duct extension
kit is required
for wall
thicknesses
greater than
600mm (23 1/2")
Refer to Frame
36.
9 WALL MOUNTING TEMPLATE
Note. The template shows the positions for the fixing holes
and the flue hole centres for standard installation. Care
must be taken to ensure the correct holes are drilled.
LEGEND
1. Terminal.
2. Weather seal.
3. Flue assembly.
4. Boiler sealing plate.
5. Flue extension tube.
REAR FLUE OUTLET
Note. Check all of the hole
positions BEFORE drilling
1. Discard both sections B of the template.
2. Tape the template into the selected position.
3. Ensure squareness by hanging a plumb line as shown.
4. Mark onto the wall (if required) the following:
a. The 8 wall mounting plate screw positions and the
lower fixing screw positions.
b. The position of the flue duct.
Note. Mark the centre of the flue hole as well as the
circumference.
5. Remove the template from the wall.

Classic Combi FF 280 - Installation
14
11 CUTTING THE FLUE - wall thicknesses of 114 to 600mm
INSTALLATION
14 FITTING THE FLUE ASSEMBLY
1. Insert the flue extension tube into the flue assembly.
2. Insert the flue assembly through the hole far enough to
allow the rubber seal to unfold completely and form an
adequate seal on the outside wall.
3. Ensure the notch is at the top - this will aid the location of
the studs into the boiler back panel.
12 FITTING THE BOILER SEALING RING
TO THE FLUE
2. Drill 3 holes 3.2mm (1/8") dia. through the outer flue duct and
boiler sealing ring. Do NOT drill the inner flue duct.
3. Insert the self tapping screws,
provided, in order to fix the boiler
sealing ring in position.
4. Stick the self adhesive foam
strip, provided in the hardware
pack, onto the flue immediately
behind the boiler sealing ring.
1. Fit the boiler sealing ring inside
the outer flue duct. Ensure the
boiler sealing ring is fully
engaged.
Ensure the notch aligns with
the groove on the outer flue
duct. This ensures correct
alignment of the flue terminal.
1. Engage the plate
(or plate and
stand-off
brackets) on the
top fixing screws.
2. Locate six No.14
x 2" screws in the
lower fixing holes
and drive home
all screws.
3. Check with a
spirit level that
the plate is
vertical.
15 WALL MOUNTING PLATE
REAR FLUE OUTLET
13 FITTING THE STAND-OFF BRACKETS
screws MUST be fitted in the top holes (marked with the
symbol) with the shakeproof washers positioned under the screw
heads.
1. Measure and note the wall thickness X.
2. Mark the wall thickness onto the flue.
3. To ensure the tube is cut square, mark the flue all the
way round.
4. Cut to length X, using the cardboard ring for support.
5. Remove the cardboard ring and remove any burrs.
Note.
If the stand-off brackets are used it is essential that 45mm
is added to the measured wall thickness when marking the
flue, to allow for the thickness of the brackets.
Installations with bottom water connections
Secure the 2 stand-off
brackets to the wall
mounting plate, using the
eight M6 nuts, screws and
shakeproof washers
provided so that the plate is
located BEHIND the front
returns of the brackets, as
shown.
Note. If the clearances
above and below the boiler
are less than the length of
the pipes to be fitted behind
the wall mounting plate, then
refer to Frame 16.
IMPORTANT. To ensure
earth continuity, securing

Classic Combi FF 280 - Installation 15
2. Extend the pipes down the wall, as shown, ensuring
that:
a. They terminate at least 50mm (2") below the bottom
of the wall mounting plate.
b. The CH flow and return pipes are vented to aid
filling.
Note. If the clearances above and below the boiler are less than the length of the pipes it will be necessary to position the pipe
runs behind the wall mounting plate BEFORE the plate is screwed to the wall.
FOR BOTH TOP AND BOTTOM WATER CONNECTIONS
If required, connection to the system pipework may now be made BEFORE the boiler is mounted on the wall.
PROCEED TO FRAME 42
INSTALLATION
17 PRE-WIRING
The mains supply and other external wiring may now be made, if required, BEFORE the boiler and Combi
modules are mounted on the wall - refer to Frames 46 to 49.
REAR & SIDE FLUE OUTLET
IMPORTANT.
For installations with bottom water connections only; the
following pipe runs must be made before the boiler is mounted
on the wall.
1. Make the connections to the fittings on top of the wall
mounting plate, as shown.
Note. For installations with a minimum top clearance of
100mm (4") the following fittings should be used.
• 22mm vented elbow (e.g. NIBCO)
• 22mm M & F elbow (e.g. ENDEX)
16 PRE-PIPING

Classic Combi FF 280 - Installation
16
INSTALLATION
18
MOUNTING THE BOILER
19 CONNECTING THE FLUE TO THE BOILER
1. Pull the flue through the wall mounting plate and locate
the 3 studs in the holes in the back panel.
2. Secure the flue to the boiler using the three M5 wing nuts
provided.
3. Pull the flue extension tube and engage onto the fan,
locate and secure with the M4 screw attached to the fan.
4. If a terminal wall plate is to be fitted proceed to Frame 34.
Note.
The sealing plate studs will locate in the back panel one way
only. This will ensure that the terminal grille is correctly
aligned.
The boiler mounts onto
the wall plate hooks and
is retained by the central
M8 screw, plain washer
and large rectangular
plate.
Note. Have ready to hand the M8 screw,
plain washer and rectangular plate supplied
in the hardware pack.
1. Lift the boiler onto the wall mounting
plate hooks as shown.
DO NOT USE THE BURNER /
CONTROLS ASSEMBLY FOR LIFTING
IMPORTANT.
The boiler module MUST be positioned
CENTRALLY on the wall mounting plate.
Refer to the index mark on the back
panel.
2. Fit the M8 screw, washer and rectangular
plate to retain the boiler.
Note.
Before fully tightening the M8 screw, check
the boiler alignment using a spirit level, and
adjust as necessary with the jacking screw -
refer to Frame 3.
DO NOT USE THE BURNER / CONTROLS ASSEMBLY FOR LIFTING
APPLIANCES FITTED WITH A REAR OUTLET FLUE: PROCEED DIRECTLY TO FRAME 38
REAR FLUE OUTLET

Classic Combi FF 280 - Installation 17
INSTALLATION
SIDE FLUE OUTLET ONLY
20
FLUE ASSEMBLY - Exploded View
For wall thickness 114mm to 600mm
1. An optional flue duct
extension kit is required for
lengths (distance from the
outside wall to the relevant
side of the boiler casing)
greater than 600mm (23 1/2")
Refer to Frame 3 .
LEGEND
1. Terminal
2. Weather seal
3. Flue assembly
4. Boiler sealing plate
5. Flue extension tube
21 WALL MOUNTING TEMPLATE
Note. The template shows the positions for the fixing holes and the flue hole centres
for standard installation.
Installations with top water connections only:
Tear off and discard the shaded portion of template B (refer to Frame 6)
Care MUST be taken to ensure the correct holes are drilled.
1. Separate the templates.
2. Tape both templates into the selected position, locating template B through an
extended centre line, as shown.
3. Ensure squareness by hanging a plumb line as shown.
4. Mark onto the wall the following:
a. The wall mounting plate screw positions (choose one from each group).
b. The 4 screw positions for the side outlet plate.
c. The position of the flue duct hole. (Ensure that the correct centre is marked,
depending upon whether the brackets are used or not)
Note. Mark the centre of the hole as well as the circumference.
d. The side of the casing nearest the flue outlet.
SIDE FLUE OUTLET
5. Remove both templates from the wall.
22 PREPARING THE WALL
IMPORTANT. Ensure that, during the cutting operation, masonry falling
outside of the building does not cause damage or personal injury.
1. Cut the flue hole preferably with a 125mm (5") core boring tool, ensuring
that the hole is square to the wall. If the hole has been accurately cut with
a drill then making good the wall faces is not essential as seals are
provided at both ends of the flue. However, both wall faces immediately
around the cut hole should be flat; make good if necessary. For less
accurate holes make good to approximately 125mm (5") diameter at the 2
wall faces.
2. Drill 8 holes with an 8mm (5/16") masonry drill and insert the plastic plugs
provided, for the side mounting plate and the wall mounting plate.
3. Drill 4 holes with a 7mm (9/32") masonry drill and insert the plastic plugs
provided for the side mounting plate.
Note. If the terminal is to be sited within 25-40mm of a corner or vertical pipe (refer to
Table 4) then the hole MUST be accurately cut and the rubber weather seal trimmed
around the groove provided. The terminal wall plate need not be fitted.
Extended centre
line
Terminal
mounting
plate screw
and flue
duct hole
positions

Classic Combi FF 280 - Installation
18
INSTALLATION
Flue assembly
26 FITTING THE FLUE ASSEMBLY
1. Insert the flue assembly through the hole far enough to
allow the rubber seal to unfold completely and form an
adequate seal on the outside wall. This will also ensure
the correct alignment of the flue terminal.
2. Ensure the notch is at the top. This will aid the location of
the studs into the boiler back panel.
25 FITTING THE BOILER SEALING RING
TO THE FLUE
1. Fit the boiler sealing ring inside the outer flue duct.
Ensure the boiler sealing ring is fully engaged.
Ensure the notch aligns with the groove on the outer flue
duct. This ensures correct alignment of the flue terminal.
2. Drill 3 holes 3.2mm (1/8") dia. through the outer flue duct
and boiler sealing ring. Do not drill the inner flue
duct.
3. Insert the self tapping screws, provided, in order to fix the
boiler sealing ring in position.
24 FITTING THE FOAM SEAL
1. To determine the position for the foam seal, measure the
wall thickness and mark it onto the flue, measuring from
the groove near the terminal.
2. Wrap the self adhesive foam strip round the flue,
ensuring that the foam is on the terminal side of the line.
This seals the gap between the flue and the wall.
23 CUTTING THE FLUE
For flue lengths 114 to 600mm ONLY
1. Measure the flue length required (i.e. the distance from
the side of the boiler to the outside face of the wall) -
refer to Frame 3.
2. Mark the flue length required on to the flue, measuring
from the groove near the terminal.
3. To ensure the tube is cut square, mark the flue all the
way round.
4. Insert the cardboard duct ring for support and cut to
length.
5. Remove cardboard duct ring and remove any burrs.
For flue lengths greater than 600mm, refer to
Frames 36 and 37- Flue extension ducts.
SIDE FLUE OUTLET

Classic Combi FF 280 - Installation 19
INSTALLATION
30 PRE-PIPING
31 PRE-WIRING
29 FITTING THE SIDE OUTLET PLATES
Note. If the boiler is fitted closer than 25mm to the side wall
the side outlet
plate must be
fitted now.
1. Split the side
outlet plate
into 2 down
the split line.
2. Fit the 2
halves of the
side outlet
plate to the
wall,
ensuring that
they are
behind the
boiler
sealing ring.
28 WALL MOUNTING PLATE
1. Locate two No.14 x
2" screws in the
wall mounting plate
top fixing holes and
screw home to
within 6mm (1/4")
of the wall surface.
2. Engage the plate
(or plate and stand-
off brackets) on the
screws.
3. Locate six No.14 x
2" screws in the
lower fixing holes
and drive home all
8 screws.
4. Check with a spirit
level that the plate
is vertical.
SIDE FLUE OUTLET
Secure the 2 stand-off brackets to the wall mounting plate,
using the eight M6 nuts, screws and shakeproof washers
provided, so that the plate is located BEHIND the front returns
of the brackets, as shown.
Note.
If the clearances above and below the boiler are less than the
length of the pipes to be fitted behind the wall mounting plate
then refer to Frame 16.
IMPORTANT.
To ensure earth continuity, securing screws MUST be fitted in
the top holes (marked with the symbol) with the shakeproof
washers positioned under the screw heads.
Installations with bottom water connections only
27 FITTING THE STAND-OFF BRACKETS
IMPORTANT.
For installations with bottom water connections only
The pipe runs shown in Frame 16 must be made before the
boiler is mounted on the wall.
For installations with both top and bottom water connections
If required, connection to the system pipework may now be
made before the boiler is mounted on the wall - proceed to
'Water Connections', Frame 42.
The mains supply and other external wiring may now be
made, if required, before the boiler and Combi modules
are mounted on the wall.
Refer to Frames 46 to 49.

Classic Combi FF 280 - Installation
20
INSTALLATION
32
MOUNTING THE BOILER MODULE Note. Have ready to hand the M8 screw, plain washer
and rectangular plate supplied in the hardware pack.
1. Lift the boiler onto the wall mounting plate hooks as
shown.
DO NOT USE THE BURNER / CONTROLS ASSEMBLY
FOR LIFTING
IMPORTANT.
The boiler module MUST be positioned CENTRALLY on
the wall mounting plate. Refer to the index mark on the
back panel
2. Fit the M8 screw, plain washer and rectangular plate to
retain the boiler.
Note.
Before fully tightening the M8 screw, check the boiler
alignment using a spirit level, and adjust as necessary
with the jacking screw - refer to Frame 3.
DO NOT USE THE BURNER / CONTROLS ASSEMBLY FOR LIFTING
The boiler mounts
onto the wall plate
hooks and is
retained by the
central M8 screw,
plain washer and
large rectangular
plate.
Terminal mounting plate
The air duct spigot engages
in the hole in the side panel.
33 CONNECTING THE FLUE TO THE BOILER
1. Pull the flue through the side outlet plate and
locate the 3 studs in the hole in the side of
the boiler.
2. Secure the flue to the boiler using the three
M5 nuts, provided.
3. Insert the flue extension tube into the flue.
4. First remove the underside screw which is
not required then fit the 900flue elbow,
supplied with the boiler, onto the fan in the
direction required. Secure in position with the
screw.
5. Pull the flue extension tube and engage onto
the fan elbow and secure with the screw.
Note.
The sealing plate studs will locate in the back
panel one way only. This will ensure that the
terminal grille is correctly aligned.
SIDE FLUE OUTLET
Wall mounting plate