Baxi MainEco Heat 15 Manual

Installation and Service Manual
Gas Fired Wall Mounted Powered Flue Condensing Boiler
en
United Kingdom
These instructions include the Benchmark Commissioning Checklist
and should be left with the user for safe keeping.
They must be read in conjunction with the Flue Installation Guide.
M
MainEco Heat
15 - 18 - 24

2 MainEco Heat 7215845 - 01 (08/14)
1 Introduction
You have just purchased one of our appliances and we thank you for the trust you have placed in our products. Please note that
the product will provide good service for a longer period of time if it is regularly checked and maintained. Our customer support
network is at your disposal at all times.
0086
ISO 9001
FM 00866
The Benchmark Scheme
Benchmark places responsibilities on both manufacturers and installers.
The purpose is to ensure that customers are provided with the correct
equipment for their needs, that it is installed, commissioned and
serviced in accordance with the manufacturer’s instructions by
competent persons and that it meets the requirements of the
appropriate Building Regulations. The Benchmark Checklist can be
used to demonstrate compliance with Building Regulations and should
be provided to the customer for future reference.
Installers are required to carry out installation, commissioning and
servicing work in accordance with the Benchmark Code of Practice
which is available from the Heating and Hotwater Industry Council who
manage and promote the Scheme. Visit www.centralheating.co.uk for
more information.
Building Regulations and the Benchmark Commissioning
Checklist
Building Regulations (England & Wales) require notification of the
installation of a heating appliance to the relevant Local Authority
Building Control Department. This can be achieved via a
Competent Persons Self Certification Scheme as an option to
notifying the Local Authority directly.
The Health & Safety Executive operates the ‘Gas Safe Register’, a self-
certification scheme for gas heating appliances.
This company is a member of the Benchmark initiative and fully
supports the aims of the programme. Its aim is to improve the
standards of installation and commissioning of central heating systems
in the UK and to encourage the regular servicing of all central heating
systems to ensure safety and efficiency.
Building Regulations require that installations should comply with
manufacturer's instructions. It is therefore important that the
commissioning checklist is completed by the installer. The relevant
section of Building Regulations only relates to dwellings. Therefore the
checklist only applies if the appliance is being installed in a dwelling or
some related structure.
The flowchart opposite gives guidance for installers on the process
necessary to ensure compliance with Building Regulations.
Model Range
Baxi MainEco Heat 15
G.C.No 41-470-15
Baxi MainEco Heat 18
G.C.No 41-470-16
Baxi MainEco Heat 24
G.C.No 41-470-17

7215845 - 01 (08/14) MainEco Heat 3
1
Installer Notification Guidelines
Choose Building
Regulations Notification
Route
Contact your relevant Local
Authority Building Control
(LABC) who will arrange
an inspection or contact
a government approved
inspector
LABC will record the data
and will issue a
certificate of compliance
‘Gas Safe Register’ will issue a
Building Regulations Compliance
Certificate to the property owner
and inform the relevant LABC
You must ensure that the
certificate number issued by
the ‘Gas Safe Register’ is written
onto the Benchmark Checklist
Scheme Members only
Call ‘Gas Safe Register’ on:
0800 408 5577
or log onto:
www.gassaferegister.co.uk
within 10 days
If you notify via the ‘Gas Safe
Register’, the register will issue
the Building Regulations
certificate on members’ behalf
Complete the
Benchmark Checklist
Install and Commission this
appliance to manufacturer's
instructions
Competent Person's
Self Certification Scheme
Building Control
Complete the
Benchmark Checklist
Install and Commission this
appliance to manufacturer's
instructions
Installer Notification Guidelines

4 MainEco Heat
Contents
Contents
1 Introduction
1.1 General
1.2 Additional Documentation
1.3 Symbols Used
1.4 Abbreviations
1.5 Extent of Liabilities
1.5.1 Manufacturer’s Liability
1.5.2 Installer’s Liability
1.6 Homologations
1.6.1 Certifications
1.6.2 Directives
1.6.3 Standards
2 Safety
2.1 General Safety Instructions
2.2 Recommendations
2.3 Specific Safety Instructions
2.3.1 Handling
3 Technical Specifications
3.1 Technical Data
3.2 Dimensions and Connections
3.3 Electrical Diagram
4 Description of the Product
4.1 General Description
4.2 Operating Principle
4.3 Main Components
4.4 Control Panel Description
4.4.1 User Interaction Controller
4.5 Standard Delivery
4.6 Accessories & Options
4.6.1 Optional Extras
5 Before Installation
5.1 Installation Regulations
5.2 Installation Requirements
5.2.1 Gas Supply
5.2.2 Electrical Supply
5.2.3 Hard Water Areas
5.2.4 Bypass
5.2.5 System Control
5.2.6 Treatment of Water Circulating Systems
5.2.7 System Details - General
5.2.8 Low Head Installation / Open
5.2.9 Sealed Systems Details
5.3 Choice of the Location
5.3.1 Location of the Appliance
5.3.2 Data Plate
5.3.3 Bath & Shower Rooms
5.3.4 Ventilation
5.3.5 Condensate Drain
5.3.6 Clearances - Access in Service
5.3.7 Flue / Chimney Location
5.3.8 Horizontal Flue / Chimney Systems
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7215845 - 01 (08/14) MainEco Heat 5
Contents
5.3.9 Flue/Chimney Trim
5.3.10 Terminal Guard
5.3.11 Flue/Chimney Deflector
5.3.12 Flue/Chimney Accessories
5.4 Unpacking & Initial Preparation
5.4.1 Unpacking
5.4.2 Initial Preparation
5.4.3 Making the Water Connection
5.4.4 Filling the Condensate Trap
5.4.5 Connecting the Condensate Drain
5.4.6 Connecting the Gas Supply
6 Installation
6.1 Air Supply / Flue Gas Connections
6.1.1 Connecting the Top Flue
6.2 Electrical Connections
6.2.1 Electrical Connections of the Appliance
6.2.2 Connecting External Devices
6.3 Filling the System
6.4 Completing the Installation
6.4.1 Completion
7 Commissioning
7.1 General
7.2 Checklist before Commissioning
7.2.1 Preliminary Electrical Checks
7.2.2 Checks
7.3 Commissioning Procedure
7.4 Gas Settings
7.4.1 ‘Chimney Sweep’ Mode
7.4.2 ‘Chimney Sweep’ Mode - Combustion Check
7.5 Configuring the System
7.5.1 Check the Operational (Working) Gas Inlet Pressure & Gas Rate
7.6 Final Instructions
8 Operation
8.1 General
8.2 Start-Up
8.3 Shutdown
8.4 Use of the Control Panel
8.5 Frost Protection
9 Settings
9.1 Parameters
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6 MainEco Heat
Contents
10 Maintenance
10.1 General
10.2 Standard Inspection & Maintenance Operation
10.3 Specific Maintenance Operation
10.3.1 Spark Ignition Electrode
10.3.2 Automatic Air Vent
10.3.3 Condensate Trap
10.3.4 Removal of Ducts
10.3.5 Pressure Switch (21 & 24 only)
10.3.6 Flow Temperature Sensor
10.3.7 Overheat Sensor
10.3.8 Return Temperature Sensor
10.3.9 Parameter Unit
10.3.10 Gas Valve
10.3.11 Control & Fan Assembly
10.3.12 User Interaction Controller
10.3.13 Setting the Gas Valve (CO2Check)
11 Troubleshooting
11.1 Error Codes - Auto Reset
11.2 Lockout Condition
12 Decommissioning Procedure
12.1 Decommissioning Procedure
13 Spare Parts
13.1 General
13.2 Spare Parts List
14 Notes
Benchmark Commissioning Checklist
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7215845 - 01 (08/14)

7215845 - 01 (08/14) MainEco Heat 7
Introduction 1
1 Introduction
1.1 General
WARNING
Installation, repair and maintenance must only be
carried out only by a competent person. This
document is intended for use by competent persons,
WARNING
Check the information on the data plate is
compatible with local supply conditions.
All Gas Safe registered engineers carry an ID card with their
licence number and a photograph. You can check your engineer
is registered by telephoning 0800 408 5500 or online at
www.gassaferegister.co.uk
This appliance must be installed in accordance with the
manufacturer’s instructions and the regulations in force. If the
appliance is sold or transferred, or if the owner moves leaving
the appliance behind you should ensure that the manual is kept
with the appliance for consultation by the new owner and their
installer. Read the instructions fully before installing or using the
appliance.
In GB, this must be carried out by a competent person as stated
in the Gas Safety (Installation & Use) Regulations (as may be
amended from time to time).
Definition of competence: A person who works for a Gas Safe
registered company and holding current certificates in the
relevant ACS modules, is deemed competent.
In IE, this must be carried out by a competent person as stated
in I.S. 813 “Domestic Gas Installations”.
The addition of anything that may interfere with the normal
operation of the appliance without express written permission
from the manufacturer or his agent could invalidate the
appliance warranty. In GB this could also infringe the Gas Safety
(Installation and Use) Regulations.
The appliance is designed as a boiler for use in residential
domestic environments on a governed meter supply only. The
selection of this boiler is entirely at the owner’s risk. If the
appliance is used for purposes other than or in excess of these
specifications, the manufacturer will not accept any liability for
resulting loss, damage or injury.
The manufacturer will not accept any liability whatsoever
for loss, damage or injury arising as a result of failure to
observe the instructions for use, maintenance and
installation of the appliance.

8 MainEco Heat
1 Introduction
7215845 - 01 (08/14)
1.3 Symbols Used
DHW: Domestic hot water
CH: Central heating
GB: Great Britain
IE: Ireland
BS: British standard
HHIC: Heating and Hotwater Industry Council
CSM: Chimney Sweep Mode
PU: Parameter Unit
PCB: Printed Circuit Board
DANGER
Risk of a dangerous situation causing serious
physical injury.
WARNING
Risk of a dangerous situation causing slight physical
injury.
CAUTION
Risk of material damage.
Signals important information .
Signals a referral to other instructions or other pages
in the instructions.
1.4 Abbreviations
1.2 Additional Documentation
These Installation & Service Instructions must be read in
conjunction with the Flue Accessories & Fitting Guide supplied in
the Literature Pack.
Various timers, external controls, flue accessories, etc. are
available as optional extras. Full details are contained in the
relevant sales literature.
In these instructions, various levels are employed to draw the
user's attention to particular information. In so doing, we wish to
safeguard the user's safety, prevent hazards and guarantee
correct operation of the appliance. Each level is accompanied by
a warning triangle

7215845 - 01 (08/14) MainEco Heat 9
Introduction 1
1.5 Extent of Liabilities
1.5.1 Manufacturer's Liability
Our products are manufactured in compliance with the
requirements of the various european applicable Directives.
They are therefore delivered with marking and all relevant
documentation. In the interest of customers, we are
continuously endeavouring to make improvements in product
quality. All the specifications stated in this document are
therefore subject to change without notice.
The manufacturer will not accept any liability for loss, damage or
injury arising as a result of:-
Failure to abide by the instructions on using the appliance.
Failure to regularly maintain the appliance, or faulty or
inadequate maintenance of the appliance.
Failure to abide by the instructions on installing the
appliance.
This company declares that no substances harmful to
health are contained in the appliance or used during
appliance manufacture.
The appliance is suitable only for installation in GB and IE and
should be installed in accordance with the rules in force, and
only used in a suitably ventilated location.
In GB, the installation must be carried out by a Gas Safe
Registered Installer. It must be carried out in accordance with
the current and relevant requirements of legislation and
guidance including the:-
• Gas Safety (Installation & Use) Regulations.
• The appropriate Building Regulations either The
Building Regulations, The Building Regulations
(Scotland), Building Regulations (Northern Ireland).
• The Water Fittings Regulations or Water Byelaws in
Scotland.
• The Current I.E.E. Wiring Regulations.
Where no specific instructions are given, reference should be
made to the relevant British Standard Code of Practice.
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.
Prior to commissioning all systems must be thoroughly
flushed and treated after installation with inhibitor (see
section 5.2.6). Failure to do so will invalidate the appliance
warranty.
Incorrect installation could invalidate the warranty and may lead
to prosecution.

10 MainEco Heat
1 Introduction
7215845 - 01 (08/14)
1.5.2 Installer's Responsibility
The installer is responsible for the installation and initial start up
of the appliance. The installer must adhere to the following:
Read and follow the instructions given in the manuals
provided with the appliance.
Carry out installation in compliance with the prevailing
legislation and standards.
Ensure the system is flushed and inhibitor added.
Install the flue/chimney system correctly ensuring it is
operational and complies with prevailing legislation and
standards, regardless of location of the boiler’s installation.
Only the installer should perform the initial start up and carry
out any checks necessary.
Explain the installation to the user.
Complete the Benchmark Commissioning Checklist - this is a
condition of the warranty !
Warn the user of the obligation to check the appliance and
maintain it in good working order.
Give all the instruction manuals to the user.
1.6 Homologations
1.6.1 Certifications
EC - Declaration of Conformity
Baxi Heating Uk Limited being the manufacturer / distributor
within the European Economic Area of the following
Baxi MainEco Heat
declare that the above is in conformity with the provisions of the
Council Directive
2009/142 EC 92/42 EEC 2004/108 EC 2006/95 EC
and has been subject to the following conformity procedures laid
down in
Annex 2 - Article 3 of 2009/142 EC
under the supervision of the British Standards Institution, a
Notified Body authorized by the United Kingdom Competent
Authority, and carrying the Notified Body Number 0086.
1.6.2 Directives
The boiler meets the requirements of Statutory Instrument “ The
Boiler (Efficiency) Regulations 1993 No3083” and is deemed to
meet the requirements of Directive 92/42/EEC on the energy
efficiency requirements for new hot water boilers fired with liquid
or gaseous fuels:-
Type test for purpose of Regulation 5 certified by:
Notified Body 0063.
Product/Production certified by:
Notified Body 0086.
For GB/IE only.

7215845 - 01 (08/14) MainEco Heat 11
Introduction 1
1.6.3 Standards
Codes of Practice - refer to the most recent version
In GB the following Codes of Practice apply:
Standard Scope
BS 6891 Gas Installation.
BS 5546 Installation of hot water supplies for domestic
purposes.
BS EN 12828 Heating systems in buildings.
BS EN 12831 Heating systems in buildings - Calculation of
load.
BS EN 14336 Installation & commissioning of water based
heating systems.
BS 6798 Installation of gas fired hot water boilers.
BS 5440 Part 1 Flues.
BS 5440 Part 2 Ventilation.
BS 7074 Expansion vessels and ancillary equipment for
sealed water systems.
BS 7593 Treatment of water in domestic hot water
central heating systems.
In IE the following Codes of Practice apply:
Standard Scope
I.S. 813 Domestic Gas Installations.
The following standards give valuable additional information;
BS 5546 Installation of hot water supplies for domestic
purposes.
BS EN 12828 Heating systems in buildings.
BS EN 12831 Heating systems in buildings - Calculation of
load.
BS EN 14336 Installation & commissioning of water based
heating systems.
BS 7074 Expansion vessels and ancillary equipment for
sealed water systems.
BS 7593 Treatment of water in domestic hot water
central heating systems.

12 MainEco Heat
2 Safety
7215845 - 01 (08/14)
2 Safety
2.1 General Safety Instructions
2.2 Recommendations
DANGER
If you smell gas:
1. Turn off the gas supply at the meter
2. Open windows and doors in the hazardous area
3. Do not operate light switches
4. Do not operate any electrical equipment
5. Do not use a telephone in the hazardous area
6. Extinguish any naked flame and do not smoke
7. Warn any other occupants and vacate the
premises
8. Telephone the National Gas Emergency Service
on:- 0800 111 999
WARNING
Installation, repair and maintenance must be carried
out by a Gas Safe Registered Engineer
(in accordance with prevailing local and national
regulations).
When working on the boiler, always disconnect the
boiler from the mains and close the main gas inlet
valve.
After maintenance or repair work, check the
installation to ensure that there are no leaks.
CAUTION
The boiler should be protected from frost.
Only remove the casing for maintenance and repair
operations. Replace the casing after maintenance
and repair operations.

7215845 - 01 (08/14) MainEco Heat 13
Safety 2
2.3 Specific Safety Instructions
2.3.1 Handling
General
• The following advice should be adhered to, from when first
handling the boiler to the final stages of installation, and
also during maintenance.
• Most injuries as a result of inappropriate handling and lifting
are to the back, but all other parts of the body are
vulnerable, particularly shoulders, arms and hands. Health
& Safety is the responsibility of EVERYONE.
• Before lifting the boiler, the circumstances of the installation
must be assessed, please use appropriate manual handling
techniques and equipment.
• Do not handle or lift unless you feel physically able.
• Wear appropriate Personal Protection Equipment
e.g. protective gloves, safety footwear etc.
Preparation
• Co-ordinate movements - know where, and when, you are
both going.
• Minimise the number of times needed to move the boiler -
plan ahead.
• Always ensure when handling or lifting the route is clear
and unobstructed. If possible avoid steps, wet or slippery
surfaces, unlit areas etc. and take special care on
ladders/into lofts.
Technique
• When handling or lifting always use safe techniques - keep
your back straight, bend your knees. Don’t twist - move your
feet, avoid bending forwards and sideways and keep the
load as close to your body as possible.
• Where possible transport the boiler using a sack truck or
other suitable trolley.
• Always grip the boiler firmly, and before lifting feel where the
weight is concentrated to establish the centre of gravity,
repositioning yourself as necessary. See the ‘Installation’
section of these instructions for recommended lift points.
Remember
• The circumstances of each installation are different. Always
assess the risks associated with handling and lifting
according to the individual conditions.
• If at any time when installing the boiler you feel that you
may have injured yourself STOP !! DO NOT ‘work through’
the pain - you may cause further injury.
IF IN ANY DOUBT DO NOT HANDLE OR LIFT THE BOILER -
OBTAIN ADVICE OR ASSISTANCE BEFORE PROCEEDING !

14 MainEco Heat
3 Technical Specification
7215845 - 01 (08/14)
3 Technical Specifications
3.1 Technical Data
NOTE: All data in this section are nominal
values and subject to normal production
tolerances.
Appliance Category CAT I 2H
Horizontal
Flue Terminal Diameter 100mm
Dimensions Projection 125mm
Outercase Dimensions
Overall Height Inc Flue Elbow - 790mm
Casing Height - 625mm
Casing Width - 370mm
Casing Depth - 270mm
Connections
Gas Supply - 22mm
Central Heating Flow
(compression fitting) - 22mm
Central Heating Return
(compression fitting) - 22mm
Condensate Drain - for 21.5mm
plastic waste pipe
Recommended System
Temperature Drop
Condensing 20°C 36°F
Heat Input (Gross) Max Min
15 model kW 18.32 8.59
18 model kW 21.75 8.59
24 model kW 28.62 8.59
Heat Output
(Non Condensing 70° C Mean Water
Temp)
Max Min
15 model kW 16 7.5
18 model kW 19 7.5
24 model kW 25 7.5
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption Max Rate
15 model W 20
18 model W 23
24 model W 33
External Fuse Rating 3A
Internal Fuse Rating (Terminal Strip)
Fuse 1.6T
Appliance Type C13 C33 C53 Nox Class 5
Water Content
litres 1.7
Static Head
max 25 metres
Low Head 0.4m min
System Detail
fully pumped open vented & sealed systems
Electrical Protection IPX4D
CO/CO2Ratio Up to a maximum
of 0.004
Flow Temperature (adjustable)
30° C to 80° C (± 5° C)
Max Gas Rate (Natural Gas - G20)
(After 10 Mins)
m3/hr
15 model 1.75
18 model 2.07
24 model 2.73
Pressure Switch
12/15/18 Model - Not Fitted
21/24 Model - Fitted
300
250
200
150
100
50
0
0.00.20.40.60.81.01.21.41.61.8
Flow (m3hr)
Pressure drop vs Flow
Pressure drop (mbar)
Clearances
Both Sides 5mm Min
Above Casing (Top Flue) 190mm Min
Above Casing (Rear Flue) 35mm Min
Below Casing (in Cupboard) 35mm Min
Below Casing 120 mm Min
Front (For Servicing) 800mm Min
Front (In Operation) 5mm Min
See Section 5.3.6 for full details !
Weights
Packaged Boiler Carton 21.5 kg
Installation Lift Weight 19.5 kg
Dynamic (nominal) Inlet Pressure
(Natural Gas - G20)
mbar 20
with a CV of 37.78 MJ/m3
15 model - 89.2% 24 model - 89.1%
18 model - 89.2%
SEDBUK 2005 Declaration
15 model - 90.2% 24 model - 90%
18 model - 90.1%
This 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 has been certified by 0063.
SEDBUK 2009 Declaration

7215845 - 01 (08/14) MainEco Heat 15
Technical Specifications 3
3.2 Dimensions and Connections
IMPORTANT: The 1.5° fall provided by the elbow is
to allow condensate to run back to the boiler, for
disposal through the condensate discharge pipe.
When using extensions the fall along the flue
system must be increased to 3°.
Where extensions are used ensure the clearance
above the top of the flue elbow (X) is as shown in
the table below:-
360° Orientation
Tube Ø 100mm
DC
B
A
E
F
At Least 3°
At Least
1.5°
Flue length (Y)
up to 1m
1m - 2m
2m - 3m
3m - 4m
4m - 5m
5m - 6m
Clearance (X)
30mm
84mm
134mm
186mm
238mm
290mm
NOTE: There must be no part of the air duct
(white tube) visible outside the property after
installation. The flue seal should fit neatly and
effect a good seal.
G
X
Y6m max
DIMENSIONS
A625mm
B270mm
C370mm
D116mm Ø Min.
E165mm
F155mm
G110mm
H550mm
For clearances see
Section 5.3.6

16 MainEco Heat
3 Technical Specifications
3.1 Technical Data (cont)
7215845 - 01 (08/14)
3.3 Electrical Diagram
Gas Valve
Safety
Thermostat
Return
Sensor
Flow
Sensor
Parameter
Unit
Pressure
Switch (where
fitted)
Electrode
User Interaction
Controller
r
b
br
bg/y
g/y
r
Not used
Loop Connector
(where no pressure
switch fitted)
Mains
Electrical
Test Point
g/y
br
b
LN
Key To Wiring Colours
b - Blue
r - Red
br - Brown
g/y - Green/Yellow
All other wires are black

7215845 - 01 (08/14) MainEco Heat 17
Description of the Product 4
4 Description of the Product
4.1 General Description
1. The Baxi MainEco Heat Range are gas fired wall mounted
powered flue condensing boilers.
2. The maximum output of the boiler is :-
15 model - 16 kW
18 model - 19 kW
24 model - 25 kW
3. The boiler modulates automatically to the system load up to
the set output. It is designed for use on Natural Gas (G20) only.
4. The two illuminated User Interaction Controller push buttons
provide information about the operating condition of the boiler.
5. The boiler is suitable for fully pumped open vented central
heating and domestic hot water systems and sealed systems.
6. An information label giving details of the model, serial number
and Gas Council number is situated on the front left underside of
the outercase and is accessed by pulling forward gently (Fig. 1).
7. The boiler data label is positioned on the inside lower right-
hand side of the boiler and can be seen when the outercase
panel is removed (Fig. 1).
8. The boiler is intended to be installed in residential/domestic
environments on a governed meter supply only.
9. The boiler must be installed with one of the purpose designed
flues such as one of the standard telescopic flue kits detailed in
the Flue Accessories & Fitting Guide.
All systems must be thoroughly cleansed, flushed and
treated with inhibitor (see Section 5.2.6).
These Installation & Servicing Instructions MUST be
read in conjunction with the Flue Accessories & Fitting Guide
supplied in the Literature Pack.
Information
Label
Flip
Downward
Fig. 1
Data Label

18 MainEco Heat
3 Technical Specifications
7215845 - 01 (08/14)
4.2 Operating Principle
1. Switched Live On: When the boiler switched live turns on
the boiler, a 20 second check cycle takes place. If the flow
temperature is less than the boiler set-point temperature the
ignition cycle will start. Pre-purge, Ignition and Burner on.
2. Fan Pre-Purge: The boiler has a 10 second pre-purge (Fan
On, Spark Generator and Gas Valve off) before the start of the
ignition sequence.
3. Ignition: The boiler has a 5 second ignition period (Fan,
Spark Generator and Gas Valve on) and burner on occurs when
a flame is detected. If a flame is not detected within the 5
second ignition period then 4 more ignition attempts are made.
If a flame is not detected after the 5 ignition attempts the boiler
goes to an ignition lock-out and an error code is displayed.
4. Burner on: After a successful ignition, Burner on occurs (Fan
and Gas Valve on, Spark Generator off). The boiler flow
temperature is controlled by varying the fan speed (and thereby
the gas rate) to achieve the optimum boiler operation. If the
boiler flow temperature exceeds the boiler set-point, the burner
will turn off (Fan and Gas Valve off).
5. Overtemperature: If a boiler overtemperature event occurs
(triggering the safety thermostat) the burner shuts down (Fan off
and Gas Valve off). A locking signal is generated and an error
code is displayed.
6. Lockout: If a lock-out error is displayed (Fan, Spark
Generator and Gas Valve off) the boiler can only be reset by
manually pressing the reset button. If 5 lock-outs are reset
within a 1 hour period then boiler becomes inoperable. It is
necessary to switch off the power supply to the boiler, and when
reinstated the reset button pressed again to operate the
appliance.
Any lock-out errors that occur regularly will require further
investigation and rectification.
Technical Enquiries: 0844 871 1555.
Mains On.
(CH or DHW demand)
Selftest cyclefor 20s
(output setting displayed)
Flow
temperature less
than set point ?
10 second pre-purge
5second ignition
Burner on
Modulate output
Ignition Lockout
Burner Off
Lockout
Mains Off
(Demand satisfied)
Flame detected ? 5th ignition attempt ?
NO
NO
NO
NO
YES
YES
YES YES
YES
Flow temp or
rate of rise too
high ?
Over Temp
Fault?

7215845 - 01 (08/14) MainEco Heat 19
Description of the Product 4
4.3 Main Components
1. Heat Exchanger
2. Combustion Control Unit
3. Condensate Trap
4. Exhaust Tube
5. Inlet Silencer
6. User Interaction Controller
7. Gas Cock
8. Air Pressure Switch (21 & 24 model only)
9. System Drain Cock
10. Air Vent
1
2
3
4
5
67
8
9
10

20 MainEco Heat
4 Description of the Product
7215845 - 01 (08/14)
4.4 Control Panel Description
4.4.1 User Interaction Controller
(Control Panel) (Fig. 2)
Key to symbols
Heating Water Temperature
Sweep Key and Status Signals
Reset button and On/Off Signal
1. The User Interaction Controller has 2 illuminating push
buttons which provide information about the operating condition
of the boiler.
2. The RESET button lights up green when the boiler has a
demand for CH or DHW.
3. The button can flash in a range of colours and at
different frequencies.
4. The User Interaction Controller also has one rotary knob. The
rotary knob can be used to set the maximum flow
temperature of the heating water.
Maximum temperature is 80°C
5. The temperature on this rotary knob must be set to a higher
temperature than the cylinder thermostat to achieve the required
hot water demand.
Fig. 2