IDEAL MINI C24 User manual

mini
C24,C28,C32
When replacing any part of this appliance, use only spare parts that you can be assured
conform to safety and performance specification that we require. Do not use
reconditioned or copy parts that have not been clearly authorised by Ideal Boilers
installation and
Your Ideal installation and servicing guide
servicing
For users guide see reverse of book
For the very latest copy of literature for specification purposes please visit our website
www.idealboilers.com where you will be able to download the relevant information in pdf format.
17962.1062.4 4307 64A4 GB
*1796210624*
S24,S28
For details of document amendments, refer to page 3
Model
Serial No.

2Mini --- Installation & Servicing

Mini Installation & Servicing 3
DOCUMENT AMENDMENTS
Relevant Installation changes implemented in this book from book reference.................17962.1062.4 2007
FFurther guidance added to Important Notes section of User Guide
Ideal Stelrad Group reserve the right to vary specification without notice

GENERAL
4Mini --- Installation & Servicing
Ta b l e 1 --- B o i l e r D a t a
Mini C24 Mini C28 Mini C32 Mini S24 Mini S28
Gas supply type & connection II2H3P G20 20mbar, G31 37mbar, 22 mm copper
Inlet / Outlet connection --- Domestic Hot Water 15 mm copper ---
Flow & return connection --- Central Heating 22 mm copper
Flue terminal diameter mm (in.) 100 (4)
Max working pressure
(sealed system)
bar (lb/in2)2.5 (36.3)
Max DHW water inlet pressure bar (lb/in2)10.0 (145.0) ---
Min DHW water inlet pressure bar (lb/in2)0.3 (4.4) ---
Electrical supply 230 Vac 50 Hz
Max power consumption W150 170 180 150 170
External fuse rating 3A
Internal fuse rating 3.15 AF
Water content --- CH litre (gal.) 1.0 (0.22) 1.1 (0.242) 1.0 (0.22) 1.1 (0.242)
Water content --- DHW litre (gal.) 0.2 (0.044) ---
Dry weight kg (lb.) 37 (81.6) 39 (86.0) 39 (86.0) 36 (79.4) 38 (83.8)
Size: Height / Width / Depth mm (in.) 703 (27 11/16”) / 400 (15 3/4”) / 310 (12 3/16”)
Lift weight kg (lb.) 35.5 (78.4) 36.5 (80.6) 36.5 (80.6) 34.5 (76.2) 35.5 (78.4)
Ta b l e 2 --- P e r f o r m a n c e D a t a --- C e n t r a l H e a t i n g
Mini C24
Mini S24
Mini C28
Mini S28
Mini C32
Max Min Max Min Max Min
Burner pressure (Hot) G20
G31
mbar
(in.w.g.)
11.7 (4.7)
35.7 (14.3)
1.8 (0.7)
6.1 (2.4)
11.7 (4.7)
35.7 (14.3)
1.8 (0.7)
5.7 (2.3)
11.7 (4.7)
35.7 (14.3)
1.8 (0.7)
6.7 (2.7)
Input based on nett CV kW
(btu/h)
26.60
(90 759)
11.00
(37 532)
31.10
(106 113)
13.00
(44 356)
35.20
(120 102)
15.50
(52 886)
Input based on gross CV kW
(btu/h)
29.52
(100 732)
12.21
(41 656)
34.52
(117 773)
14.43
(49 230)
39.07
(133 306)
17.20
(58 686)
Output kW
(btu/h)
24.30
(82 912)
9.10
(31 049)
28.40
(96 901)
10.80
(36 850)
32.00
(109 184)
12.70
(43 332)
Gas consumption (Hot) G20
G31
l/s (ft3/h)
l/s
0.763 (97.0)
0.309
0.315 (40.1)
0.128
0.892 (113.5)
0.361
0.373 (47.4)
0.151
1.010 (128.4)
0.400
0.444 (56.5)
0.176
Seasonal efficiency* (SEDBUK)
%
Band D
78.2
Band D
78.3
Band D
78.3
NOx classification Class 3 Class 2 Class 3
*The value is used in the UK Government’s Standard Assessment Procedure (SAP) for energy rating of dwellings.
The test data from which it has been calculated have been certified by a notified body.
Ta b l e 3 --- P e r f o r m a n c e D a t a --- D o m e s t i c H o t W a t e r
Mini C24 Mini C28 Mini C32
Maximum
Burner pressure (Hot) G20
G31
mbar
(in.w.g.)
11.7 (4.7)
35.7 (14.3)
11.7 (4.7)
35.7 (14.3)
11.7 (4.7)
35.7 (14.3)
Input based on nett CV kW (btu/h) 26.60 (90 759) 31.10 (106 113) 35.20 (120 102)
Input based on gross CV kW (btu/h) 29.52 (100 732) 34.52 (117 773) 39.07 (133 306)
Output kW (btu/h) 24.30 (82 912) 28.40 (96 901) 32.00 (109 184)
Gas consumption (Hot) G20
G31
l/s (ft3/h)
l/s
0.763 (97.0)
0.309
0.892 (113.5)
0.361
1.010 (128.4)
0.400
Flow 35 ˚Ctemp.rise l/m (gpm) 10.0 (2.2) 11.6 (2.6) 13.1 (2.9)
Domestic hot water specific
rate
l/m (gpm) 11.6 (2.6) 13.6 (3.0) 15.3 (3.4)
Note: the gas consumption is calculated using a calorific
value of 38.7 MJ/m3(1038 Btu/ft3) gross or 34.9 MJ/m3(935
Btu/ft3) nett.
To obtain the gas consumption at different calorific value: ---
a. FOR L/S --- divide the gross heat input (kW) by the gross
C.V. of the gas (MJ/m3)
b. FOR FT3/H --- divide the gross heat input (Btu/h) by the
gross C.V. of the gas (Btu/ft3)
Key to Symbols:
IE = Ireland, GB = United Kingdom (Countries of destination)
PMS = Maximum operating pressure of water
C12 C32 C52 = a room sealed appliance designed for
connection via concentric ducts to a horizontal or vertical
terminal or twin flue system.
II2H3P = appliance designed for use on 2nd family gas group
H or 3rd family gas group 3P
CAUTION. To avoid the possibility of injury during the installation, servicing or cleaning
of this appliance care should be taken handling edges of sheet steel components.

GENERAL
Mini Installation & Servicing 5
Mini
Boiler size G.C. appliance No. PI No.
(Benchmark No.)
Mini C24 47---348---18 0694BM3420
Mini C28 47---348---19 0694BM3420
Mini C32 47---348---25A 0694BM3420
Mini S24 41---392 ---98 0694BM3420
Mini S28 41---392 ---99 0694BM3420
Destination countries: GB, IE
CONTENTS
Air supply 9
Benchmark Commissioning Checklist 58
Boiler clearances 6
Boiler exploded view 13
Electrical connections 19
Electrical supply 10
Fault finding 48
Flow wiring diagram 22
Flue fitting 15
Gas conversion 29
Gas safety regulations 7
Gas supply 8
Installation 14
Mandatory requirements 7
Replacement of components 34
Servicing 30
Shortlistofparts 55
Thermostatic radiator valves 11
Water connections 18
Water treatment 9
Wiring diagrams 20
For GB, to comply with Building Regulations Part L1 (Part J in Scotland) the boiler should be fitted in accordance with the
manufacturer’s instructions. Self --- certification that the boiler has been installed to comply with Building Regulations can be
demonstrated by completing and signing the Benchmark Commissioning Checklist.
BENCHMARK COMMISSIONING CHECKLIST DETAILS
Boiler Page
Make and model 5
Appliance serial no. on data badge 13
SEDBUK No. % 4
Controls
Time and temperature control to heating 24/25
Time and temperature control to hot water 24/25
Heating zone valves 24
TRV’s 11
Auto bypass 11
Boiler interlock 11
For all boilers
Flushing to BS.7593 9
Inhibitor 9
Central heating mode
Heat input to be calculated
Boiler Page
Burner operating pressure measure and record
Central heating flow temp. measure and record
Central heating return temp. measure and record
For combination boilers only
Scale reducer 11
Hot water mode
Heat input to be calculated
Max. operating burner pressure measure and record
Max. operating water pressure measure and record
Cold water inlet temp measure and record
Hot water outlet temp. measure and record
Water flow rate at max. setting measure and record
For condensing boilers only
Condensate drain n/a
For all boilers: complete, sign & hand over to customer
For assistance see Technical Helpline on the back page
NOTE TO THE INSTALLER: COMPLETE
THE BENCHMARK COMMISSIONING
CHECKLIST AND LEAVE THESE
INSTRUCTIONS WITH APPLIANCE

GENERAL
Mini --- Installation & Servicing
6
1 BOILER WATER CONNECTION
65 (2 9/16”)
85 (3 5/16”)
255 (10”)
561 (22 1/16”) 101 (4”)
83 (3 1/4”)
65 (2 9/16”) 52 (2”) 64 (2 1/2”)
Wall
mounting
plate
CH return
CH flow
DHW hot outlet *
DHW cold inlet *
Gas inlet
20 (3/4”)
Pipe size O.D. mm
CH flow 22
CH return 22
Gas inlet 22
DHW cold inlet * 15
DHW hot outlet * 15
* Pipe connections not used on system boilers
2 BOILER CLEARANCES
All dimensions in mm (in.)
The following minimum clearances must be maintained for
operation and servicing. Additional space will be required for
installation, depending upon site conditions.
25 (1”) 50 (2”)
200 (7 7/8”)
254 (10”)
Bottom clearance
The bottom clearance, after installation, can be reduced to
20mm. However, 200mm must be available for servicing.
Front clearance
The minimum front clearance when built into a cupboard is
50mm (2”) from the cupboard door. However 450mm
(17 3/4”) overall clearance is still required, with the cupboard
door open, to allow for servicing.
Side and Rear Flue
a. Providedthattheflueholeiscutaccurately,e.g.withacore
drill, the flue can be installed from inside the building where
wall thickness does not exceed 600 mm (24”).
Where the space into which the boiler is going to be installed
is less than the length of flue required the flue must be fitted
from the outside.
installation from inside ONLY
b. If a core boring tool is to be used inside the building the
spaceinwhichtheboileristobeinstalledmustbeatleast
wide enough to accommodate the tool.
147 (5 3/4”)
92 (3 5/8”)
200 (7 7/8”) 200 (7 7/8”)

GENERAL
Mini Installation & Servicing 7
INTRODUCTION
Mini C24,Mini C28 and Mini C32 are wall mounted, low
water content, balanced flue combination gas boilers.
Mini S24 and Mini S28 are wall mounted, low water content,
balanced flue system gas boilers.
Central heating (CH) output and domestic hot water (DHW)
output (on combination versions) are both fully modulating:
--- between 9.10 (31 049) and 24.30 (82 912) kW (btu/h) for
model Mini C24 and Mini S24;
--- between 10.80 (36 849) and 28.40 (96 900) kW (btu/h) for
model Mini C28 and Mini S28.
--- between 12.70 (43 435) and 32.00 (109 184) kW (btu/h) for
model Mini C32.
Theboilersaresuitableforconnectiontofullypumped,
pressurised sealed water systems ONLY.
AsystembypassisnotrequiredwhenTRV’sarefittedtoall
radiators (see Frame 5). The boiler incorporates an automatic
bypass.
A circulating pump, pressure gauge, safety valve and heating
expansion vessels are provided.
The CH flow temperature is controlled by a temperature
probe. In DHW mode the boiler modulates to sustain a
nominal adjustable water flow temperature of 55 ˚C.
The boiler casing is of white painted mild steel with a
drop --- down controls access door.
The boiler temperature control is located behind the control
panel door.
The main heat exchanger is made of copper.
The DHW heat exchanger is stainless steel.
The system pipework must include drain cocks in appropriate
places. Pipework may be taken downwards.
For upwards pipework installation an additional frame
(optional) must be used (see frame 18).
OPTIONAL EXTRA KITS
Programmer Kit (Mini C24,Mini C28,Mini C32 only) fits
neatly within the casing. Separate fitting instructions are
included with the kit. Note. If using an alternative programmer
read Frame 26 first.
Horizontal Concentric Extension Ducts
Up to 4 m (13’ 1”) for models:
Mini C24,Mini S24,Mini C28,Mini S28.
Up to 2,7 m (8’ 10”) for model Mini C32
Other available kits are listed in frame 9.
DHW OPERATION (combi versions)
With no call for CH the boiler fires only when DHW is drawn
off. When there is a call for CH, the heating system is supplied
at the selected temperature until DHW is drawn off. The
output is then directed by the diverter valve to heat the
secondary heat exchanger and supply a maximum draw---off
of:
Mini C24. 10.0 (2.2) l/min (gpm) at 35 degree rise.
Mini C28 11.6 (2.6) l/min (gpm) at 35 degree rise.
Mini C32 13.1 (2.9) l/min (gpm) at 35 degree rise.
The nominal DHW temperature is 55 ˚C, but water drawn off
when the boiler has been on for central heating may be hotter
than this, for a short period of time.
GAS SAFETY
Current Gas Safety (Installation and Use)
Regulations or rules in force
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 must be carried out by a CORGI
Registered Installer. It must be carried out in accordance with
the relevant requirements of the:
FGas Safety (Installation and Use) Regulations
FThe appropriate Building Regulations either The Building
Regulations, The Building Regulations (Scotland),
Building Regulations (Northern Ireland).
FThe Water Fittings Regulations or Water byelaws in
Scotland.
FThe Current I.E.E. Wiring Regulations.
Where no specific instructions are given, reference should be
made to the relevant British Standard Code of Practice.
In IE, the installation must be carried out by a Competent
Person 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.
Detailed recommendations are contained in the following
British Standard Codes of Practice:
BS 5440:1 Flues (for gas appliances of rated input not
exceeding 70 kW).
BS 5440:2 Ventilation (for gas appliances of rated input
not exceeding 70 kW).
BS. 5449 Forced circulation hot water systems.
BS. 5546 Installation of gas hot water supplies for
domestic purposes (2nd Family Gases)
BS 6700 Design, installation testing and maintenance of
services supplying hot water for domestic use.
BS. 6798 Installation of gas fired hot water boilers of
rated input not exceeding 70 kW.
BS. 6891 Low pressure installation pipes.
Health & Safety Document No. 635.
The Electricity at Work Regulations, 1989.
The manufacturers notes must NOT be taken, in any way, as
overriding statutory obligations.
IMPORTANT These appliances are CE certificated for safety
and performance. It is, therefore,importantthatnoexternal
controldevices,e.g.fluedampers,economisersetc.,are
directly connected to these appliances unless covered by
these Installation and Servicing Instructions or as otherwise
recommended by Ideal Stelrad Group. in writing. If in doubt
please enquire.
Any direct connection of a control device not approved by
Ideal Stelrad Group. could invalidate the certification and the
normal appliance warranty. It could also infringe the Gas
Safety Regulations and the above regulations.
SAFE HANDLING OF SUBSTANCES
Care should be taken when handling the boiler insulation
panels, which can cause irritation to the skin. No asbestos,
mercury or CFCs are included in any part of the boiler in its
manufacture.
LOCATION OF BOILER AND FLUE OUTLET
The boiler must be installed on a flat and vertical wall, capable
of adequately supporting the weight of the boiler and any
ancillary equipment.

GENERAL
Mini --- Installation & Servicing
8
The boiler may be fitted on a combustible wall and 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 Institute of Gas Engineers
document IGE/UP/7, 1998.
Bathroom Installations
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.
For Ireland reference should be made to the current ETCI
rules for electrical installations and I.S.813:2002
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.
Note. It is not permissible to install a mains socket in a
bathroom.
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 air cupboard installation, are
to conform to the following:
FBS 6798 (No cupboard ventilation is required --- see “Air
supply” for details)
FThe position selected for installation MUST allow
adequate space for servicing in front of the boiler.
FFor 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
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.
Natural gas boilers must be installed on a gas supply with a
governed meter. A gas meter can only be connected by the
local gas supplier or by a registered CORGI engineer.
Propane gas boilers MUST be installed with pipes, cylinders
and pressure regulators fitted in accordance with BS.5482.1.
Bulk tank installations MUST comply with the Home Office
code of practice for storage of liquefied petroleum gas at fixed
installations. The complete installation MUST be tested for
gas soundness and purged as described in the above code.
The boiler is adjusted at the factory for use with the relevant
supply gas. A working gas pressure equal to that stated in
Table 1 MUST be available at the boiler inlet.
Where applicable, the appliance can be converted for
G20---Natural Gas or G31--- Propane Gas by using the
appropriate conversion kit.
IMPORTANT Installation pipes MUST be fitted in accordance
with BS. 6891. In IE refer to I.S. 813.2002.
Pipework from the meter to the boiler MUST be of an
adequatesize,i.e.notlessthan22mmO.D.copperor3/4”
BSP iron.
FLUE INSTALLATION REQUIREMENTS
Thefluemustbeinstalledinaccordancewiththe
recommendations of BS. 5440 ---1 2000.
In IE refer to I.S. 813.2002.
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.
Ensure that the guard is fitted centrally.
5 Where the terminal is fitted within 850mm (34”) of a plastic
or painted gutter or 450mm (18”) of painted eaves then an
aluminium shield at least 750mm (30”) long should be
fitted to the underside of the gutter or painted surface
fitted centrally above the flue.
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--- 1:2000. In IE refer to I.S. 813.2002.
Table 4 --- Balanced flue terminal position
Terminal position Minimum spacing
1 Directly below, above or along side
of an openable window, air vent or
other ventilation opening
300 mm (12”)
2 Below guttering, drain pipes or soil
pipes
75 mm ( 3”) **
3 Below eaves 200 mm ( 8”) **
4 Below balconies or a car port roof 300 mm ( 12”) **
5 From vertical drain pipes or soil
pipes*
60 mm ( 2 1/2”) **
6 From an internal or external corner
or to a boundary along side the
terminal
150 mm ( 6”) **
7 Above adjacent ground, roof or
balcony level
300 mm (12”)
8 From a surface or a boundary
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”)
* If the terminal is within 150mm of any vertical soil or drain
pipe, an aluminium shield at least 400mm (15 3/4”) long
should be fitted equi ---distant from the terminal and close to
the pipe.
** If a reduction down to 25mm(1”) is required in any of the
indicated positions, horizontal flue kit no. 200889 MUST be
used. Only 1 reduction down to 25mm is allowable per
installation.

GENERAL
Mini Installation & Servicing 9
Vertical Terminals
13 Above the roof pitch with roof
slope of all angles.
Above flat roof
300 mm (12”)
300 mm (12”)
14 From single wall face
From corner wall faces
600 mm (24”)
1000 mm (40”)
Twin Flue Applications
15 Centre distance between air inlet
and flue outlet ducts
120mm (5”) ***
*** Where the twin flue ducts are positioned at or near the
above minimum centres the wall sealing gaskets should be
trimmed to allow them to fit flat to the wall. This should be
done for both inside and outside wall gaskets.
Terminals guards are available from boiler suppliers --- ask for
Tower Flue Guard, Model K6. In case of difficulty seek advice
from:
Grasslin UK Ltd.,Tower house, Vale Rise, Tonbridge,
Kent TN9 1TB Tel. [phone] Fax No. +44 (0)
1732 354 455 www.tfc---group.co.uk
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,
labelled as “unsafe” until corrective action taken.
AIR SUPPLY
It is NOT necessary to have a purpose---provided air vent in
the room or internal space in which the boiler is installed.
Neither is it necessary to ventilate a cupboard or
compartment in which the boiler is installed, due to the low
surface temperatures of the boiler casing during operation;
therefore the requirements of BS6798, Clause 12, BS 5440:2
and in IE I.S. 813:2002 may be disregarded.
WATER CIRCULATION SYSTEM
The boilers are designed for connection to pressurised, fully
pumped, sealed water central heating systems ONLY. The
domestic hot water (DHW) calorifier is incorporated within the
combi boiler and only requires connection to the mains water
supply.
Additional Pumps.
The boiler is supplied with an integral circulating pump. If the
boiler is to be used in conjunction with any additional
circulating pumps, please contact the Technical Helpline for
advice on application.
IMPORTANT
A minimum length of 1m of copper pipe MUST be fitted to
both flow and return connections from the boiler before
connection to any plastic piping.
Ensure that the mains water supply pressure is adequate to
provide the required DHW flow rate. Refer to Table 1 on
page 4.
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
BS. 5546 and BS. 6700.
Copper tubing to BS 2871:1 is recommended for water
carrying pipework and MUST be used for pipework carrying
potable water.
Any soldered joints on potable water pipework MUST NOT be
made with solder containing lead.
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 or ventilated underfloor spaces.
Draining taps should be at least 1/2” BSP nominal size and
be in accordance with BS 2879.
WATER TREATMENT
Central Heating
Antifreeze fluid, corrosion and scale inhibitor fluids suitable for
use with boilers having copper heat exchangers may be used
in the central heating system.
IMPORTANT
The application of any other treatment to this product
may render the guarantee of Ideal Stelrad Group
INVALID.
Ideal Stelrad Group recommend Water Treatment in
accordance with the Benchmark Guidance Notes on Water
Treatment in Central Heating Systems.
Ideal Stelrad Group recommend the use of Fernox, GE Betz
Sentinel or Salamander water treatment products, which must
be used in accordance with the manufacturers instructions.
Notes.
1. It is most important that the correct concentration of the
water treatment products is maintained in accordance with
the manufacturers’ instructions.
2. If the boiler is installed in an existing system any unsuitable
additives MUST be removed by thorough cleansing.
BS 7593:2006 details the steps necessary to clean a
domestic heating system.
3. In hard water areas, treatment to prevent lime scale may be
necessary --- however, the use of artificially softened water is
NOT permitted.
4. Under no circumstances should the boiler be fired before
the system has been thoroughly flushed.
Domestic Hot Water
In hard water areas where mains water can exceed 200ppm
Total Hardness (as defined by BS 7593:2006 Table 2) a scale
reducing device should be fitted into the boiler cold supply
within the requirements of the local water company. The use
of artificially softened water, however, is NOT permitted.
Ideal Stelrad Group recommend the use of Fernox
Qantomat, Sentinel Combiguard and Calmag CalPhos I scale
reducing devices, which must be used in accordance with the
manufacturers’ instructions.
For further information contact:
Fernox
Cookson Electronics
Forsyth Road
Sheerwater
Woking
Surrey
GU21 5RZ
[phone]
Calmag Ltd.
Unit 4--- 6 Crown Works
Bradford Road
Sandbeds
Keighley
West Yorkshire
BD20 5LN
[phone]
Salamander (Eng) Ltd
Reddicap Trading Estate
Sutton Coldfield
West Midlands
B75 7BY
[phone]
Sentinel Performance
Solutions
The Heath Business &
Technical Park
Runcorn
Cheshire
WA7 4QX
[phone]

GENERAL
Mini --- Installation & Servicing
10
3 ELECTRICAL SUPPLY
Warning. This appliance must be efficiently earthed.
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. For Ireland reference should be
made to the current ETCI rules for electrical installations.
The point of connection to the mains should be readily
accessible and adjacent to the boiler, except for bathroom
installations where 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.
4 SEALED SYSTEM REQUIREMENTS
Central Heating
Note. Mini boilers are suitable for fully pumped pressurised
sealed systems only.
REQUIREMENTS
1 General
The installation must comply with the requirements of
BS. 6798 and BS. 5449.
2 Flow Temperature
The installation should be designed to work with flow
temperatures of up to 90 ˚C.
3 Working Pressure
All components of the system must be suitable for a working
pressureof3bar(45lb/in
2) and temperature of 110 ˚C. Extra
care should be taken in making all connections so that the
risk of leakage is minimised.
The following components are incorporated within the
appliance:
a. Circulating pump.
b. Safety valve; with a non---adjustable pre --- set lift pressure of
3 bar (45lb/in2).
c. Pressure gauge; covering a range of 0 ---4 bar.
d1. 6 litre expansion vessel; with an initial charge pressure of
0.7 bar (10.5 lb/in2)forMini C24,Mini C28,Mini S24 and
Mini S28.
d2. 7 litre expansion vessel; with an initial charge pressure of
1.0 bar (15.0 lb/in2)forMini C32.
For further details refer to BS.5449:1 and the British Gas
Corporation publication ’Specifications for Domestic Central
Heating and Hot Water’.
4 Filling the system
Fill the system 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 shall be used to facilitate filling.
When installing the filling connection provided with the boiler
an additional WRAS approved valve must be fitted to the
mains water supply upstream of the double check valve to
fully comply the Water Regulations
CH return
Hose unions Mains
Water
Supply
Temporary hose
(disconnect
after filling)
Stop valve Additional stop valve
Double check valve
assembly
Note direction of flow
System filling and make---up
Proceed with the following:
FThoroughly flush out the whole of the system with cold
water before fitting the boiler.
FFill and vent the system until the pressure gauge registers
1.5bar(22lb/in
2). Examine for leaks.
FRelease water from the system until a pressure of 1 bar
(15 lb/in2) is reached.
To avoid getting debris on the valve seat, do not use
the safety valve to do this.
FLight the boiler and heat the system to the maximum
working temperature. Examine for leaks.
FTurn off the boiler and drain the system while still hot.
FRefill and vent the system.
FRe ---pressurise the system to the desired charge pressure
(see Table 5).
Table 5 Mini C24, Mini S24, Mini C28, Mini S28
System charge pressure
(bar)
0.5 0.7 1.0
Safety valve setting 3.0
Vessel pre ---charge pressure
(bar)
0.7
System volume (litres) Volume of expansion vessel
in addition to 6 litre unit
fitted to boiler
75 --- --- ---
100 0.3 0.8 1.4
125 1.8 2.5 3.2
150 3.4 4.2 5.0
175 5.0 6.0 7.0
200 6.5 7.6 8.7
225 8.1 9.3 10.6
250 9.6 11.1 12.4
275 11.2 12.8 14.3
300 12.8 14.5 16.1
Multiply this factor by
system volume and deduct
6 litres to obtain size of
additional vessel for other
system volumes.
0.063 0.069 0.074
5 Size of expansion vessel
For the system water expansion to be contained by the 6litre
expansion vessel fitted to the following models:
Mini C24,Mini S24,Mini C28,Mini S28
the cold system volume must not exceed:
96 litres when pressurised to 0.5 bar (cold)
88 litres when pressurised to 0.7 bar (cold)
81 litres when pressurised to 1.0 bar (cold)
If the pressure exceeds 2.65 bar when the boiler is up to
temperature with all radiators in use then an additional
expansion vessel MUST be installed on the return pipework.

GENERAL
Mini Installation & Servicing 11
For expansion volumes see Table 5.
Ta b l e 6 M i n i C 3 2
System charge pressure
(bar)
0.5 0.7 1.0
Safety valve setting 3.0
Vessel pre ---charge pressure
(bar)
0.7
System volume (litres) Volume of expansion vessel
in addition to 7 litre unit
fitted to boiler
75 --- --- ---
100 --- --- 0.4
125 0.8 1.6 2.3
150 2.5 3.4 4.1
175 4.0 5.1 6.0
200 5.6 6.8 7.8
225 7.2 8.6 9.7
250 8.8 10.3 11.5
275 10.3 12.0 13.4
300 11.9 13.7 15.2
Multiply this factor by
system volume and deduct
7 litres to obtain size of
additional vessel for other
system volumes.
0.063 0.069 0.074
For the system water expansion to be contained by the 7litre
expansion vessel fitted to the following model:
Mini C32
the cold system volume must not exceed:
111 litres when pressurised to 0.5 bar (cold)
101 litres when pressurised to 0.7 bar (cold)
95 litres when pressurised to 1.0 bar (cold)
If the pressure exceeds 2.65 bar when the boiler is up to
temperature with all radiators in use then an additional
expansion vessel MUST be installed on the return pipework.
For expansion volumes see Table 6.
Guidance on vessel sizing is given in BS 7074:1 and BS 5449
For IE refer to the current edition of I.S. 813.
6 Hydraulic Loss
Remaining pump capacity
Flow rate l/hour
mH2O
0
1
2
3
4
5
6
0 200 400 600 800 1000 1200 1400
7 Draining the system
Draining taps MUST be located in accessible positions to
permit the draining of the whole central heating system,
including the central heating side of the boiler. The taps
should be at least 1/2” BSP nominal size and be in
accordance with BS 2879.
5 BOILER CONTROL INTERLOCKS
Thermostatic radiator valves.
Ideal Stelrad Group. 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 as
stated in BS5449. 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 heat
requirement of at least 10% of the boiler output, is achieved
using a room thermostat whilst other rooms are individually
controlled by TRV as stated in BS5449.
For further information refer to “Good Practise Guide 143” a
publication of the energy efficiency office, available from the
building research establishment Garston Watford WD2 7JR
tel: [phone]
The boiler is fitted with an automatic internal bypass. No
further system bypass is required.
Typical installation
DA
TRV
B
Room
T/stat
Balancing valve
TRV
TRV
6 DOMESTIC HOT WATER
REQUIREMENTS
1 The domestic hot water service must be in accordance
with BS 5546 and BS 6700.
2 For the minimum and maximum working pressures of the
Mini C24,Mini C28 and Mini C32 domestic hot water
circuit refer to Table 1, page 4.
3 The cold water supply pipe should be flushed before
fitting the boiler.
4 The boilers are suitable for connection to most types of
washing machine and dishwashing appliances.
5 When connecting to suitable showers,i.e.thosedesigned
for modulating domestic hot water, ensure that:
a. The cold inlet to the boiler is fitted with an approved
anti---vacuum or syphon non---return valve.
b. Hot and cold supplies are of equal pressure.
6 Hard water areas
In areas where the water is ’hard’ it is recommended that
a proprietary scale---reducing device is fitted into the boiler
cold supply, within the requirements of the local water
company.

GENERAL
Mini --- Installation & Servicing
12
7BOILERWATERCIRCUITDIAGRAM
M i n i C 2 4 --- M i n i C 2 8 --- M i n i C 3 2
32
1
2
34
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
23 24
25
22
26
27
28
29
30
31
33
Mini S24 --- Mini S28
33
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
23 24
25
22
26
27
28 29
30
31
1 Domestic hot water (DHW) heat exchanger
2 Domestic hot water (DHW) flow switch
3 Domestic hot water (DHW) outlet pipe
4 Domestic cold water inlet cock
5 Three--- way diverter valve
6 Main circuit drainage cock
7 Central heating flow cock
8 B y --- p a s s v a l v e
9 Central heating (CH) return cock
10 3 bar pressure relief valve
11 Gas cock
12 Expansion vessel
13 Gas valve inlet pressure tap
14 Modulating gas valve
15 Burner pressure tap
16 Flame detection electrode
17 Ignition electrodes
18 Burner
19 Combustion chamber
20 Primary heat exchanger
21 Fan
22 Air pressure switch
23 Venturi device
24 Flue outlet pipe
25 Air intake pipe
26 Automatic air vent
27 Overheat thermostat
28 Pump
29 Pump vent plug
30 CH temperature probe
31 CH flow switch
32 DHW temperature probe
33 CH circuit temperature/pressure gauge

INSTALLATION
Mini Installation & Servicing 13
8 B O I L E R A S S E M B LY ---
Exploded View
19
2
35
13
28
7
9
20
4
1
25 23
5
15
18*
14
16
17
26
12
10
27*
29*
30
11*
31
32
34
33
8
6
3
22
36
2124
P5
1Venturi
2Fan
3 Flue hood
4 Flame detection electrode
5 Overheat thermostat
6 Primary heat exchanger
7 Inner case cover
8 Ignition electrodes
9 Heat exchanger return pipe
10 CH temperature probe
11 DHW temperature probe
12 Main circuit drainage cock
13 Auto air vent
14 Pump
15 Electronic control pcb
16 3 bar pressure relief valve
17 Return manifold
18 DHW flow switch*
19 Right hand panel
20 Boiler front panel
21 Appliance data badge (inside)
22 Left hand panel
23 CH circuit pressure gauge
24 Model identification & instructions
25 Control panel door
26 CH flow switch
27 3 way diverter valve*
28 Heat exchanger flow pipe
29 DHW heat exchanger*
30 Bypass pipe
31 Gas valve
32 Gas valve outlet pipe
33 Injector manifold
34 Burner
35 Air pressure switch
36 Expansion vessel
INSTALLATION
*Mini C24,Mini C28 and Mini C32 only

INSTALLATION
Mini --- Installation & Servicing
14
9 UNPACKING
The boiler is supplied fully assembled in one pack A, together
with a standard flue assembly for lengths up to 960 mm
(37” 3/4), rear or side flue outlet, in pack B.
Unpack and check the contents.
Pack A contents
ATheboiler.
B Hardware pack
C Wall mounting plate
D Wall mounting template
E Installation & Servicing instructions.
F The User’s Instructions.
G Filling loop assembly
H Restrictor pack
A
B
C
D
EF
GH
Hardware pack contents
F22 mm CH connection pipe --- 2 off.
F22 mm Gas supply connection pipe --- 1 off.
F15 mm DHW cold inlet connection pipe --- 1 off. *
F15 mm DHW hot outlet connection pipe --- 1 off. *
F1/2” connection nut --- 2 off. *
F1/2” sealing washer --- 3 off. *
F3/4” sealing washer --- 6 off.
F3/4” Gas supply isolating valve --- 1 off.
F3/4” CH circuit isolating valve --- 2 off.
F1/2” DHW cold inlet isolating valve --- 1 off. *
*Mini C24,Mini C28 and Mini C32 only
Pack B contents
I Air intake pipe ø 100 mm (4”)
J Flue pipe ø 60 mm (2” 3/8) with terminal grille assembly
KBand
L Turret---air pipe gasket
M Fluepipegaskets---2off
N Boiler ---turret gasket
O Flue turret
P Self tapping screws 4,8x13 --- 4 off
Q Self tapping screw 4,2x13 --- 2 off
R Wall finishing gaskets --- 2 off
J
I
K
L
M
N
O
P
R
Q
Optional extras, if ordered, are available in separate boxes.
FElectronic programmer kit *
FExtension duct kit pack D (ø 60/100)
FFlue support kit
FVertical outlet flue kit with elbow (ø 60/100)
F90˚Elbow kit (ø 60/100)
F45˚Elbow kit (ø 60/100)
FRoof flue kit (ø 80/125)
FPitched roof tile (for roof flue kit)
FFlat roof tile (for roof flue kit)
FExtension duct kit (ø 80/125)
F90˚Elbow kit (ø 80/125)
F45˚Elbow kit (ø 80/125)
FCondense drain (ø 80/125)
FTwin pipe kit (ø 80) with air and flue terminals
FExtension duct kit (ø 80)
F90˚Elbow kit (ø 80) female ---female
F90˚Elbow kit (ø 80) male---female
F45˚Elbow kit (ø 80) male---female
FCondense drain (ø 80)
FCondense trap
FStand---off bracket
FPre---piping frame
FNatural gas to LPG conversion kit
FLPG to natural gas conversion kit
10 PACKAGING
To unpack the boiler refer to the instructions on carton end
flap.
INSTALLATION

INSTALLATION
Mini Installation & Servicing 15
11 FITTING THE FLUE SYSTEM
The maximum total equivalent lengths are given in
Table 7 and Table 8 for co---axial pipes ø 60---100 mm,
Ta b l e 9 f o r c o --- a x i a l p i p e s ø 8 0 --- 1 2 5 m m a n d i n t h e
diagrams for the ø 80 mm twin pipes air ---flue systems.
Refer to the assembly instructions contained within the
chosen flue kit packaging for the correct assembly and
installation.
Condensate Collection
When a length of vertical pipe is used in the system and the
length of flue exceeds the following, a condensate drain and
trap must be fitted to the lowest point of the system.
The trap must be connected to a suitable waste pipe.
ø80---125mm co---axial pipes --- 1 metres
ø80twinfluepipes---7metres
Flue Restrictors
Two different sized restrictors are supplied with the
boilers Mini C24, Mini S24, Mini C28, Mini S28.
A 44 mm size is fitted to the boiler and a 47 mm size is
supplied in a separate bag.
Two different sized restrictors are supplied with the boiler
Mini C32
A 47 mm size is fitted to the boiler and a 50 mm size is
supplied in a separate bag.
The appropriate restrictor, when necessary, must be fitted in
the flue outlet elbow as indicated in following picture.
For the correct use of the restrictors with co---axial pipes
ø 60/100 mm refer to:
Table 7 for models Mini C24,Mini S24,Mini C28,Mini S28.
Table 8 for model Mini C32
For the correct use of the restrictors with vertical roof kit ø
80/125 mm refer to:
Table 9 for models Mini C24,Mini S24,Mini C28,Mini S28
Table 10 for model Mini C32.
Table 7 --- Models Mini C24, Mini S24, Mini C28, Mini S28
Pipe length (ø 60/100) Restrictor
Between 0,5 (19.5“) and 1 m (39“) ø44mm
More than 1 m (39“) up to 2 m (78.5“) ø47mm
More than 2 m (78.5“) up to 4 m (157“) no restrictor
Ta b l e 8 --- M o d e l M i n i C 3 2
Pipe length (ø 60/100) Restrictor
Between 0,5 (19.5“) and 1 m (39“) ø47mm
More than 1 m (39“) up to 2,7 m (8’ 10“) no restrictor
Table 9 --- Models Mini C24, Mini S24, Mini C28, Mini S28
Pipe length (ø 80/125) Restrictor
Between 0,5 (19.5“) and 1,5 m (59“) ø44mm
More than 1,5 m (59“) up to 6,5 m (21’ 4“) ø47mm
More than 6,5 m (21’ 4“) up to 8,5 m
(27’ 10“)
no restrictor
Ta b l e 1 0 --- M o d e l M i n i C 3 2
Pipe length (ø 80/125) Restrictor
Between 0,5 (19.5“) and 4 m (13’ 1“) ø47mm
More than 4 m (13’ 1“) up to 6 m (19’ 8“) no restrictor
For the correct use of the restrictors with twin pipes refer to
the following diagram for the models Mini C24,Mini S24,
Mini C28 and Mini S28.
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32
Flue exhaust (m)
Air intake (m)
Mini C24
Mini S24
Mini C28
Mini S28
Allowed values
Restrictor
47 mm
No
Restrictor
Refer to the following diagram for the model Mini C32.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Flue exhaust (m)
Air intake (m)
Mini C32
Restrictor
50 mm
No
Restrictor
Allowed values
INSTALLATION

INSTALLATION
Mini --- Installation & Servicing
16
11 FITTING THE FLUE SYSTEM (cont.)
Co---axial Flue kits.
Horizontal.
For calculation of total flue length, the distance MUST be
measured from the centreline of the concentric elbow to the
end of the terminal grille.
Vertical outlet
For calculation of total flue length, the distance MUST be
measured from the centreline of the outlet connector at the
boiler top panel to the end of the terminal grille.
For each additional 45˚and 90˚flue bend used, the
maximum permissible length of flue system must be reduced
by 1m or 1,5m respectively.
Horizontal and Vertical Outlet kits (60---100) have a minimum
300mm length, up to a maximum shown in tables 7 & 8.
Cutting lengths of flue and air ducts
Measure the wall thickness and, when using a side outlet, the
gapbetweentheinnerwallandtheboilersidecasing.
Use the following chart to calculate the cutting length of air
duct.
Completely insert the flue duct in the air duct.
Mark and cut the flue duct so it protrudes 27 mm from the air
duct edge.
Groove
Cut this end Flue duct
12
Horizontal Concentric
Air duct
Rear Outlet Wall thickness + 67 mm
Rear outlet + Stand --- off Wall thickness + 102 mm
S i d e O u t l e t --- L H & R H Wall thickness + Gap + 120mm
Twin pipe flue kits
For calculation of total flue length, the distance MUST be
measured from the centreline of the flue duct/air duct
connection to the end of the flue outlet grille/air inlet duct.
For each additional 45˚M&F and 90˚M&F flue bend used,
themaximumpermissiblelengthoffluesystemmustbe
reduced by 0,9m or 1,65m respectively.
For each additional 90˚F&FFluebendused,themaximum
permissiblelengthoffluesystemmustbereducedby2,75m.
Lengths of allowable equivalent flue outlet and air inlet ducts
are indicated in the graphs within this frame.
N.B.: The air intake and flue outlet must not terminate on
opposite sides of the building.
Cutting lengths of flue and air ducts
Measure the wall thickness and, when using a side outlet, the
gap between the inner wall and the boiler side casing. Use
the following chart to calculate the cutting lengths of both flue
and air ducts.
Twin Pipe
Air duct
Rear Outlet Wall thickness + 215 mm
Rear outlet + Stand --- off Wall thickness + 250 mm
Side Outlet --- LH Wall thickness + Gap + 83 mm
Side Outlet --- RH Wall thickness + Gap + 273mm
Flue Duct + Grille
Rear Outlet Wall thickness + 225 mm
Rear outlet + Stand --- off Wall thickness + 260 mm
Side Outlet --- LH & RH Wall thickness + Gap + 278mm
When installing a horizontal flue system, Co---axial or
Twin Pipe, all ducts MUST have a fall of 3% AWAY from
the boiler.
12 REAR FLUE ASSEMBLY
Legend
1 Wall finishing gaskets
2 Self tapping screw 4,2x13
3 Self tapping screws 4,8x13
4 Flue turret
5 Boiler --- turret gasket
6 Fluepipegaskets
7 Turret---air pipe gasket
8Band
9 Flue pipe ø 60 mm with terminal grille assembly
10 Air intake pipe ø 100 mm
9
10
8
76
5
4
3
12
INSTALLATION

INSTALLATION
Mini Installation & Servicing 17
13 WALL MOUNTING TEMPLATE
(rear flue)
IMPORTANT
Detailed installation steps are given directly on the wall
mounting template
1 Tape the template into the selected position.
2 Ensure squareness by hanging a plumbline.
3 Mark onto the wall the following:
a. the wall mounting plate screw positions
b. the position of the flue duct.
(Mark the centre of the hole as well as the circumference)
4 Remove the template from the wall
a
b
14 WALL MOUNTING TEMPLATE
(side flue)
IMPORTANT
Detailed installation steps are given directly on the wall
mounting template
1 Tape the template into the selected position.
2 Ensure squareness by hanging a plumbline.
3 Mark onto the wall the following:
a. the wall mounting plate screw position
b. Extend the centre line as shown.
Mark the flue duct centre from the corner (see diagram
and template)
Note. mark the centre of the hole as well as the
circumference.
4 Remove the template from the wall
Extended centre
Spirit level
15 DRILLING THE WALL
Rear flue shown
IMPORTANT
Ensure that, during the cutting operation, masonry falling
outside the building does not cause damage or personal
injury.
1 Cut the flue hole (preferably with a 5” core boring tool),
ensuringthattheholeissquaretothewall.
2 Drill the fixing holes with an 8mm (5/16”) masonry drill.
Fit suitable wall plugs (not provided).
Note. If the teminal is to be sited within 25---40 mm 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.
5” diameter
flue hole
Section
through wall
Note: Check all of the hole
positions before drilling.
INSTALLATION

INSTALLATION
Mini --- Installation & Servicing
18
16 FITTING THE WALL
MOUNTING PLATE
Refer to frame 18 for service connections.
Fit the wall mounting plate
Directly to the wall
FOffer up wall mounting plate.
FScrew through the fixing holes using 3 off no. 14x2”
screws (not provided).
FCheck alignment with spirit level.
FTighten screws.
17 MOUNTING THE BOILER
Lift the boiler onto the wall mounting plate locating the bar at
the rear of the back panel assembly into the bracket.
As added protection, the boiler should be lifted with the lower
polystyrene packaging in place.
Lower the boiler into position.
Remove the lower packaging. Remove the front and side
panels (refer to frame 21) and strip off the protective coating.
The panels may be placed to one side and re--- fitted when the
installation is complete.
Fit the horizontal flue system referring to the instructions
contained with the kit.
Make good the internal wall surface using the seal provided.
18 CONNECTIONS
Fit the service valves, washers and tail pipes as shown.
Central Heating flow
Domestic hot
water outlet * Gas inlet
Domestic cold
water inlet * Central Heating return
*Mini C24,Mini C28 and Mini C32 only
Connect to the tail pipes by proprietory fittings.
The pipework may be directed down or through the rear wall
as required.
The pipework may be directed upwards by using an optional
additional frame available in separate box. See illustration for
upward pipework routing Mini C shown
INSTALLATION

INSTALLATION
Mini Installation & Servicing 19
19 SAFETY VALVE DRAIN
The discharge pipe should be positioned so that the
discharge of water or steam cannot create a hazard to the
occupants of the premises or damage to electrical
components and wiring.
Pressure
Discharge pipe
relief valve
20 ELECTRICAL CONNECTIONS
Warning. This appliance MUST be efficiently earthed
A mains supply of 230 V ~ 50 Hz is required.
Mains wiring should be 3 core PVC insulated flexible cord
NOT LESS than 0.75 mm2(24 x 0.2mm) and to BS. 6500,
Table 16. (0.5mm2flex is not acceptable --- for mechanical,
not electrical reasons.)
Mains wiring external to the boiler MUST be in accordance
with the current I.E.E. (BS7671) Wiring Regulations and any
local regulations.
For Ireland reference should be made to the current ETCI
rules for electrical installations.
The supply connection is intended to be made via a double
pole switch having a 3 mm (1/8”) contact separation in both
poles, serving only the boiler and system controls. A 3 pin
UNSWITCHED socket may, alternatively, be used.
The fuse rating should be 3.15 AF.
Mini C24, Mini C28 Mini C32 only
For external controls wiring see frame 26.
Note: the switch contacts of any external programmer,
room or frost thermostat must be volt free.
Connecting a switched live feed to external controls
terminal block may be dangerous and will result in
serious damage to the boiler.
For Mini S24, Mini S28 refer to frame 27.
21 ELECTRICAL CONNECTIONS
Incoming mains wiring detail
To gain access to the power supply and external controls
terminal blocks:
1 Remove the screws A and the front panel of the case.
A
2 Remove the screws B.
3 Loosen the screws C.
C
B
B
C
4 Remove the side panels or move the lower part of the side
panels and pull the control panel.
When completely pulled out, the panel can rotate 45˚
downwards to facilitate the operations on the internal parts.
5 Loosen the screws D and remove the service panel.
D
12
LN
3
Mains
Power supply
terminal block
External controls
terminal block
Mini C24,Mini C28 ,
Mini C32 only
Thermostat link.
Remove when wiring
external thermostats.
Refer to frames 26 and 27
Note: Ensure that the lengths of the current conductors are
shorter than the earth conductor so that if the cable slips in its
anchorage the current carrying conductors become taut
before the earth conductor.
INSTALLATION

INSTALLATION
Mini --- Installation & Servicing
20
22 PICTORIAL WIRING
Mini C24, Mini C28, Mini C32
LD1LD2LD3
F1
F2
K1 K3 K4
LD4
P4
X6
X1 X7
P5
SB1
X5
K2
X3
X2
X4
123
LN M
~3
2
1
X11
M
~
t
t
Ignition
electrodes Flame detection
electrode
External controls
terminal block
Electric supply
terminal block Three way diverter valve Pump Fan
M
~
Primary circuit
flow switch Air pressure switch
D.h.w. flow
switch C.h. temperature probe NTC Modulating
gas valve
Safety
thermostat
D.h.w. temperature
probe NTC
bn = brown
bu = blue
bk = black
wh = white
rd = red
gy = grey
gn = green
ye = yellow
vt = violet
og = orange
gnye = green/yellow
bu
bn
gnye
bu bn bk
bn bu
bn bu bk
bu bn
gnye
bn
bu bk bu bn bk bu bn
bu bk
gnyebu
bk
gnye
bk
bk
gy
gy
gy
gy
bn bu
bk
rd
rd
bk
bk
bk
bk
ye
gy
bu bu
rd
bu
wh
X8
ye
rd rd
gy
wh bu
rd
bu
bu bk
bn bubu
Wiring diagram for boiler equiped with electronic control p.c.b. type: Bertelli & Partners DIMS11---SA03/16740
NC
COM
NO
rd
wh
gn
bk
Time switch
Electronic control P.C.B.
LD1LD2LD3
F1
F2
K1 K3 K4
LD4
P4
X6
X1 X7
P5
SB1
X5 K2
X3
X2
X4
X8
1 2 3 4 7 8 95 10 11 12 13 14
15 16
17 18 19
20
21
22
23 24
25
26
27
28 29 30 31 32 33 34 35 36 37 38
Electronic
control p.c.b.
Pin position ref. numbering
39
6
rd
rd
bu
bn
bu
INSTALLATION