Baxi MainEco Combi 24 User manual

D
Duo-tec Combi
User Guide
Gas Fired Wall Mounted Condensing Combination Boiler
24 - 28 - 33 - 40
28 LPG
en
United Kingdom
Please keep these instructions in a safe place.
If you move house, please hand them over to the next occupier.

2© Baxi Heating UK Ltd 2015
© Baxi Heating UK Ltd 2015 All rights reserved. No part of this publication may
be reproduced or transmitted in any form or by any means, or stored in any
retrieval system of any nature (including in any database), in each case whether
electronic, mechanical, recording or otherwise, without the prior written
permission of the copyright owner, except for permitted fair dealing under
Copyrights, Designs and Patents Act 1988.
Applications for the copyright owner’s permission to reproduce or make other
use of any part of this publication should be made, giving details of the proposed
use, to the following address:
The Company Secretary, Baxi Heating UK Ltd,
Brooks House, Coventry Road, Warwick. CV34 4LL
Full acknowledgement of author and source must be given.
WARNING: Any person who does any unauthorised act in relation to a
copyright work may be liable to criminal prosecution and civil claims for damages.
1.0 Quick Reference Guide 3
2.0 Troubleshooting 4
3.0 Repressurising System 6
4.0 Clearances 7
5.0 Care of the Boiler 8
6.0 Legislation 9
7.0 Warranty & Service 10
8.0 ErP Information 12
9.0 Notes 16
10.0 Emergency 19
11.0 Disposal 19
Section Page
Contents
Boiler Controls - see opposite page
for Operating Quick Reference Guide
0086
ISO 9001
FM 00866
The Benchmark Scheme
Baxi Heating UK Ltd is a licensed member of the Benchmark Scheme which aims
to improve the standards of installation and commissioning of domestic heating
and hot water systems in the UK and to encourage regular servicing to optimise
safety, efficiency and performance.
Benchmark is managed and promoted by the Heating and Hotwater Industry
Council. For more information visit www.centralheating.co.uk
Natural Gas
Baxi Duo-tec 24 Combi ErP
G.C.No47 075 96
Baxi Duo-tec 28 Combi ErP
G.C.No47 075 97
Baxi Duo-tec 33 Combi ErP
G.C.No47 075 99
Baxi Duo-tec 40 Combi ErP
G.C.No47 077 03
Propane
Baxi Duo-tec 28 LPG Combi ErP
G.C.No47 075 98

1.0 Quick Reference Guide
3
© Baxi Heating UK Ltd 2015
bar
0
1
2
3
4
bar
0
1
2
3
4
ON/OFF/Reset
Selector Switch
Display Central Heating
Temperature Control
Domestic Hot Water
Temperature Control
System Pressure Gauge
OFF Position
The boiler will not operate.
Central Heating Temperature Control
Turn the knob clockwise to increase or anticlockwise to decrease the temperature.
Range 25 - 80° C.
Domestic Hot Water Temperature Control
Turn the knob clockwise to increase or anticlockwise to decrease the temperature.
Central Heating Indicator - The indicator will illuminate when the boiler is in the central
heating mode.
Domestic Hot Water Indicator - The indicator will illuminate when hot water is being
supplied to a tap or shower.
Burner On Indicator - The indicator will illuminate when the burner has fired and is heating
your central heating or domestic hot water.
Boiler Output Temperature - In either the central heating or domestic hot water position
the display will illuminate showing the current boiler temperature in degrees centigrade.
Central Heating System Pressure - The normal operating water pressure is between 1 and
2.0 bar. If the pressure exceeds 3 bar the safety pressure valve will operate and a fault is
indicated. Contact your Installer.
Central Heating & Hot Water
Both Heating & Hot Water will operate.
Reset
Hold for approx 5 seconds and release.
Display
Position of
Optional Timer

2.0 Troubleshooting
4© Baxi Heating UK Ltd 2015
START
Make sure the gas supply is
turned ON and check if other
gas appliances are operating
(e.g. fire, cooker).
If no gas, consult your
supplier.
Is the ON/OFF/Reset
Select Switch in the
( ) position ?
Is the ( ) or ( ) light on
and the ( ) on ?
Check electricity to the
boiler is switched on.
Is the display lit ?
Display
Central Heating
Indicator
Domestic Hot
Water Indicator
Burner On
Indicator
Boiler operating satisfactorily.
bar
0
1
2
3
4
Is the Central Heating System
Pressure between 1 and 2.5
bar ?
If the reading falls below 1 bar
repressurise the system as
described in section 3.1.
Does the display show an error
code e.g. E133, E110 ?
Boiler not working
NO
NO
YES YES
YES
NO
Turn the ON/OFF/Reset
Selector Switch to Reset.
Error Code E119 showing low
pressure.
NO
YES
YES
NO
If boiler does not
Reset

2.0 Troubleshooting
5
© Baxi Heating UK Ltd 2015
Is the Timer ON and calling for
heat ?
Ensure timer is set for Central
Heating ON (see any
instructions supplied with
timer).
Is the Room Thermostat (if
fitted) set high enough ?
15
10
5
20
25
15
10
5
20
25
Turn Room Thermostat to
maximum setting (typical
example shown).
If you don’t know what you need to do to
get the boiler to light, or need help with
the system and controls, contact your
installer as soon as possible.
YES
NO
CONTACT YOUR
INSTALLER OR
SERVICE ENGINEER.
YES
12
1
2
3
4
5
6
7
8
9
10
11
Typical
examples of
external timer
NO

3.0 Repressurising System
6© Baxi Heating UK Ltd 2015
bar
0
1
2
3
4
bar
0
1
2
3
4
3.1 Central Heating System Pressure
1. The normal operating water pressure is between 1
and 2.5 bar (Fig. 1). If the pressure exceeds 3 bar the
safety pressure valve will operate and a fault is indicated.
Contact your installer.
2. It may be necessary to repressurise the system
occasionally (Fig. 2). A filling device (the filling loop) will
be fitted on the system. This will be on the boiler itself,
or on pipework near to the boiler.
3. If you are unsure of its position, or cannot identify it,
consult the installer who fitted the boiler.
4. The filling loop consists of two taps and a separate
copper pipe with connection fittings.
5. Only when repressurising should the copper pipe be
connected between the two taps. Ensure that the nuts
on the pipe ends are tightened onto the taps.
6. Fully open one of the taps first, and then while
watching the pressure gauge, carefully open the second
tap.
7. When the needle on the gauge is indicating 1 or more
turn both taps off.
8. Disconnect the copper pipe from the taps (a small
amount of water may be present) and remove it. Keep
the pipe in a safe place for future use.
Fig. 1
Fig. 2
Normal Pressure
Requires
Repressurising

4.0 Clearances
7
© Baxi Heating UK Ltd 2015
Fig. 3
Fig. 4
150mm Min*
780mm
450mm
200mm Min
(300mm Min if
using 80/125mm
flueing system
5mm Min
5mm Min
450mm Min
For Servicing
Purposes
In Operation
5mm Min 4.1 For your Safety
1. This appliance must have been installed in accordance
with the manufacturer’s instructions and the regulations
in force.
2. Any modification 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.
3. Your boiler must not be operated without the casing
correctly fitted.
4. Do not interfere with any sealed components on this
boiler.
5. Take note of any warning labels on your boiler.
6. Your boiler should have the following minimum
clearances for Safety and Maintenance
(Figs. 3 & 4):-
Top - 200mm
Bottom - 150mm
Left side - 5mm
Right Side - 5mm
Front - 5mm (In Operation)
- 450mm (For Servicing)
*This is the MINIMUM recommended dimension.
Greater clearance than this will aid installation and
maintenance.
7. If your boiler is installed in a compartment, do not use
it for storage purposes. Do not obstruct any purpose
provided ventilation openings.
8. Flammable materials must not be stored in close
proximity to your boiler.
9. Avoid skin contact when your boiler is in operation, as
some surfaces may get hot e.g. pipework.
10. Ensure that the flue terminal, outside the house,
does not become damaged or obstructed, particularly
by foliage.
11. It is important that the condensate drain system is
not blocked, modified or damaged in any way as this
would affect the operation of your boiler. Your installer
should have insulated any exposed pipework.
GB - Heating Industry definition meaning England, Scotland,
Wales, Northern Ireland, Isle of Man and the Channel Isles

5.0 Care of the Boiler
8© Baxi Heating UK Ltd 2015
5.1 Cleaning the Outer case
The painted panels should be wiped with a damp cloth and
then dried completely. DO NOT USE ABRASIVE
CLEANING AGENTS.
5.2 Protection & Precaution
1. The boiler incorporates an integral frost protection feature
that will operate in both modes. If the boiler temperature falls
below 5° C, then the boiler will operate until the water
temperature has been raised.
2. If a system frost thermostat has been fitted (your installer
will be able to advise you), then to operate correctly and
protect your system, the gas and electricity must be left on and
the appliance set in the central heating mode.
3. The boiler incorporates an integral pump protection feature
which continually monitors the time since the pump last
operated. To prevent seizure, the pump will operate for
approximately 1 minute if it has not run in the last 24 hours.
5.3 Fault Indication
1. If a fault occurs on the boiler an error code may be shown
on the facia display.
2. The codes are either two or three digit, preceded by the
letter 'E'. For example, code E133 will be displayed by 'E1'
alternating with '33'. E50 is shown as 'E' then '50'.
3. E20, E28, E50, E125 & E160 indicate faulty components.
You should make a note of the displayed error code and
contact your installer or service engineer.
4. If E110 or E130 is displayed overheat of the primary water
or flue system has occurred. Turn the selector switch to the
reset position and hold for at least 5 seconds. If the boiler
does not relight, or the code is displayed regularly contact your
installer or service engineer.
5. E119 is displayed when the primary water pressure is less
than 0.5 bar. After repressurising the system the boiler should
operate. Your installer will be able to advise you about the
method of repressurising. See page 6 for further details.
6. E133 indicates that the gas supply has been interrupted,
ignition has failed or the flame has not been detected. Ensure
that the gas supply has not been turned off, and turn the
selector switch to the reset position and hold for at least 5
seconds. If the boiler does not relight, or the code is displayed
regularly contact your installer or service engineer.
Central Heating NTC Fault
Flue NTC Fault
Hot Water NTC Fault
Safety Thermostat Operated
Water Pressure Switch Not Operated
Circulation Fault (Primary Circuit)
Flue NTC Operated
Interruption Of Gas Supply or Flame Failure
Fan or Fan Wiring Fault
E20
E28
E50
E110
E119
E125
E130
E133
E160
Table of Error Codes
bar
0
1
2
3
4
Display
Then
Fig. 5

6.0 Legislation
9
© Baxi Heating UK Ltd 2015
6.1 Installation, Commissioning, Service & Repair
1. This appliance must be install in accordance with the
manufacturer’s instructions and the regulations in force. Read
the instructions fully before installing or using the appliance.
2. In GB, this must be carried out by a competent person as
stated in the Gas Safety (Installation & Use) Regulations.
3. 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.
4. In IE (Eire), this must be carried out by a competent person
as stated in I.S. 813 “Domestic Gas Installations”.
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
The boiler meets the requirements of Statutory Instrument
“The Boiler (Efficiency) Regulations 1993 No 3083” 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 0085.
Product/Production certified by:
Notified Bodies 0086.
For GB/IE only.
6.2 Benchmark Commissioning Checklist
1. Please ensure that the installer has fully completed the
Benchmark Checklist on the inside back pages of the
installation instructions supplied with the product and that you
have signed it to say that you have received a full and clear
explanation of its operation. The installer is legally required to
complete a commissioning checklist as a means of complying
with the appropriate Building Regulations (England and Wales).
2. All installations must be notified to Local Area Building
Control either directly or through a Competent Persons
Scheme. A Building Regulations Compliance Certificate will
then be issued to the customer who should, on receipt, write
the Notification Number on the Benchmark Checklist.
3. This product should be serviced regularly to optimise its
safety, efficiency and performance. The service engineer should
complete the relevant Service Record on the Benchmark
Checklist after each service.
4. The Benchmark Checklist may be required in the event of
any warranty work.

7.0 Warranty & Service
10 © Baxi Heating UK Ltd 2015
7.1 General
To make sure your boiler warranty is activated and maintained,
it is essential that the:
1. Benchmark checklist is completed by your installer
2. Warranty is registered with Baxi
3. Boiler has an annual service
Please note that failure to adhere to terms and conditions will
make your warranty invalid.
7.2 Standard Warranty Terms and Conditions
Warranty Registration, Service & Repair
For full terms and conditions, visit www.baxi.co.uk/terms.
Benchmark Checklist
The Benchmark Checklist will be completed by your installer
and records that the boiler has been installed and
commissioned correctly. It can be found at the back of the
installation and service manual and should be kept in a safe
place for the life of the boiler. We will check that the
Benchmark Checklist has been completed on an in-warranty
visit.
Ways to register your warranty
If your boiler is eligible for an extended warranty, your installer
may register the product on your behalf and provide you with
the relevant documentation. Please check with your installer.
Should this not be the case, you can register your warranty
online at www.baxi.co.uk/registration
To activate a standard two year warranty, please use one of
the following methods:
• Freephone 0800 013 7989 or
• Return the enclosed registration card

7.0 Warranty & Service
11
© Baxi Heating UK Ltd 2015
Annual Service
A service must be completed every 12 months from the
date of installation to maintain your warranty.
This service must be completed by one of the following:
• A Gas Safe registered installer/engineer
• Baxi Customer Support; call us 0344 871 1525
Please make sure that your engineer has logged the service
information at the back of the installation and service manual.
You will be asked for your service history on any in-warranty
repair visit.
If you experience a problem with your boiler
For any in or out of warranty repair, Baxi Customer Support is
on hand to help you. Call our award-winning team to arrange
for one of our nationwide team of Gas Safe registered
engineers to visit.
If your product is in warranty, everything is free of charge,
subject to our warranty terms and conditions. If it is out of
warranty, we can still help and offer a range of options you can
choose from to suit your needs.
Contact Baxi Customer Support 0344 871 1525
Opening hours
Monday - Friday, 8.00am - 6.00pm
Weekends and Bank Holidays, 8.30am - 2.00pm
Please note calls may be recorded for training and monitoring
purposes.
When contacting Baxi Customer Support, please have the
following information to hand:
• Boiler serial number. This can be found on the
appliance.
• Proof of purchase if you do not have the boiler
serial number.
Please note that for in-warranty repairs, our engineers will ask
to see your service history record, completed Benchmark
Checklist and details of your installer. These can all be found in
the installation and user manual.
Information Label

8.0 ErP Information
12 © Baxi Heating UK Ltd 2015
8.1 Product Fiche - Combination Boilers
Productfichefor combination boilers
Spaceheating - Temperatureapplication
Baxi Duo-tec Combi ErP
MediumMediumMediumMedium
Water heating - Declared loadprofileXL
Seasonal spaceheating energy efficiency class
Water heating energy efficiency class
A
A
A
A
A
A
A
A
A
A
Rated heatoutput
(Prated or Psup)
kW
Spaceheating - Annual energy consumption kWh
GJ
Water heating - Annual energy consumption kWh
GJ
Seasonal spaceheating energy efficiency %
Water heating energy efficiency %
Sound power level LWA indoors dB
See
24 28
Medium
28 LPG4033
For specific precautions aboutassembling, installing and maintaining
consulttherelevant section as detailed on theContents page.
XL XL XL XL
20 24 28 32 24
17391 20870 24348 27826 20870
63 75 88 100 75
18 18 18 18 18
92 92 92 92 92
84 81 83 84 81
50 53 52 50 53

13
© Baxi Heating UK Ltd 2015
8.0 ErP Information
8.2 Package Fiche - Boilers
Package fichefor boilers indicating thespaceheating energy efficiency of thepackage
AD-3000743-01
%
1
‘I’
2
%+
3
%( - ‘I’ ) x 0.1 = ±
4
%(‘III’ x + ‘IV’ x ) x 0.9 x ( /100) x = +
(1)
A* = 0.95, A = 0.91,
B = 0.86, C = 0.83,
D - G = 0.81
5
%( - ‘I’ ) x ‘II’ = +
6
%0.5 x 0.5 x = -
54
<30%
G F E D C B A A
+A ++ A +++
%+ (50 x ‘II’) =
7
7
%
ecivedralosfoehcfimorf
pmuptaehyratnemelppuSDNAnoitubirtnocraloS
noitubirtnocraloS
dellatsniecnoycneicfifeygrenelautcastiotdnopserroctonyamehcfisihtnirofdedivorpstcudorpfoegakcapehtfoycneicfifeygreneehT
in a building, as this efficiency is infl u enced by further factors such as heatloss in thedistribution system and thedimensioning of the
products in relation to building sizeand characteristics.
?C°53tasrettimetaeherutarepmetwolhtiwdellatsnipmuptaehyratnemelppusdnarelioB
egakcap
fossalcycneicfifeygrenegnitaehecapslanosaeS
egakcapfoycneicfifeygrenegnitaehecapslanosae
S
RO
)%ni(ycneicfifeygrenegnitaehecapslanosaeS
pmuptaehyratnemelppuS
gnitarknaT
ni(ycneicfiferotcelloC
%)
)³mni(emulovknaT)²mni(ezisrotcelloC
)%ni(ycneicfifey
grenegnitaehecapslanosaeS
reliobyratnemelppuS
,%5.1=IIIssalC,%2=IIssalC,%1=IssalC
Class IV = 2%, Class V = 3%, Class VI = 4%,
Class VII = 3.5%, Class VIII = 5%
lortnocerutarepmeT
reliobfoycneicfifeygrenegnitaehecapslanosaeS
59.0esu,AevobasignitarknatfI)1(
eulavrellamstceles
pmuptaehfoehcfimorf
pmuptaehfoehcfimorf
reliobfoehcfimorf
lortnocer
utarepmetfoehcfimorf
I
Thevalueof theseasonal spaceheating energy efficiency of the
preferential spaceheater, expressed in %.
II
Thefactor for weighting theheatoutputof preferential and supple
mentary heaters of a package as set outin thefollowing table.

14 © Baxi Heating UK Ltd 2015
8.0 ErP Information
8.2 Package Fiche - Boilers (cont)
Package efficiency
Temperaturecontrol X
Baxi Duo-tec Combi ErP
%
Temperaturecontrol Y %
Thevalueof themathematical expression: 294/(11 ʷPrated),
whereby ‘Prated’ is related to thepreferential spaceheater.
Thevalueof themathematical expression 115/(11 ʷPrated),
whereby ‘Prated’ is related to thepreferential spaceheater.
Weighting of boilers
00 0
0.1 0.3 0.37
0.2 0.55 0.70
0.3 0.75 0.85
0.4 0.85 0.94
0.5 0.95 0.98
0.6 0.98 1.00
≥ 0.7 1.00 1.00
(1) Theintermediate values arecalculated by linear interpolation between thetwoadjacent values.
(2) Prated is related to thepreferential spaceheater or combination heater.
III
IV
I
V
Psup / (Prated + Psup)(1)(2) II, package withouthot water storage tank II, package with hot water storage tank
24 403328 28 LPG

15
© Baxi Heating UK Ltd 2015
8.0 ErP Information
8.3 Package Fiche - Combination Heaters (Boilers
or Heat Pumps
Package fichefor combination heaters (boilers or heatpumps) indicating thewater heating energy efficiency of the
package
AD-3000747-01
%
1
‘I’
2
%(1.1 x ‘I’ - 10%) x ‘II’ - - ‘I’ = +
‘III’
<28%
XXL
XL
L
M
G F E D C B A A
+A ++ A +++
3
%
%+ 0.4 x =
23
%- 0.2 x =
23
dellatsniecnoycneicfifeygrenelautcastiotdnopserroctonyamehcfisihtnirofdedivorpstcudorpfoegakcapehtfoycneicfifeygreneehT
in a building, as this efficiency is infl u enced by further factors such as heatloss in thedistribution system and thedimensioning of the
products in relation to building sizeand characteristics.
etamilcegarevarednuegakcapfossalcycneicfifeygrenegnitaehretaW
etamilcegarevarednuegakc
apfoycneicfifeygrenegnitaehretaW
yticirtceleyrailixuA
noitubirtnocraloS
retaehnoitanibmocfoycneicfifeygrenegnitaehretaW
ecivedralosfoehcfimorf
:redloC
:remraW
snoitidnocetamilcremrawdnaredlocrednuycneicfifeygrenegnitaehretaW
:elfiorpdaolderalceD
I
Thevalueof thewater heating energy efficiency of thecombination
heater, expressed in %.
II
Thevalueof themathematical expression (220 ʷQref)/Qnonsol,
whereQrefis taken from Regulation EU811/2013, Annex VII Table
15 and Qnonsolfrom theproductficheof thesolar devicefor thede
clared loadprofileM, L, XL or XXL of thecombination heater.
III
Thevalueof themathematical expression (Qaux ʷ2,5)/(220 ʷQref),
expressed in %, whereQaux is taken from theproductficheof the
solar deviceand Qreffrom Regulation EU811/2013, Annex VII Ta
ble15 for thedeclared loadprofileM, L, XL or XXL.

9.0 Notes
16 © Baxi Heating UK Ltd 2015

9.0 Notes
17
© Baxi Heating UK Ltd 2015

9.0 Notes
18 © Baxi Heating UK Ltd 2015

10.0 Emergency
19
© Baxi Heating UK Ltd 2015
Gas Tap
Heating Flow, Heating
Return and Mains Water
Inlet Isolating Valves
Fig. 6
In an Emergency
If a water or gas leak occurs or is suspected, the boiler can
be isolated at the inlet valves as follows;
1. Using a suitable open ended spanner, turn the square
nut on the gas tap through 90° (1/4turn) to isolate the gas
supply at the boiler (Fig. 6).
2. The water isolating valves are positioned under the
boiler and can be closed by turning their taps to the right
towards the wall (Fig. 6).
3. Call your Installer or Service Engineer as soon as
possible.
If you smell gas
Do not operate light switches
Do not operate any electrical equipment
Do not use a telephone in the hazardous area
Extinguish any naked flame and do not smoke
Open windows and doors in the hazardous area
Turn off the gas supply at the meter
Warn any other occupants and vacate the premises
Telephone the National Gas Emergency Service on:-
0800 111 999
LPG Appliance (Duo-tec 28 LPG Combi ErP)
If your boiler operates on LPG familiarise yourself with
any control and isolation valves. If in doubt consult your
installer about the operation of these devices.
Faulty boiler
If it is known or suspected that a fault exists
on the boiler, it must not be used until the fault
has been corrected by a competent person.
Warning !
11.1 Disposal and Recycling
NOTE: Removal and disposal of the boiler must be
carried out by a qualified person in accordance with
local and national regulations.
11.0 Disposal

7219666 - 01 (04/15)
0086
Baxi Customer Support
0344 871 1525
Opening hours
Monday - Friday, 8.00am-6.00pm
Weekends and Bank Holidays, 8.30am-2.00pm
Please note calls may be recorded for training and monitoring purposes
baxi.co.uk
Register now to activate your warranty:
www.baxi.co.uk/registration
For the warranty to be maintained, please make sure...
Benchmark checklist is completed
Warranty is registered with Baxi
The boiler has an annual service
1
2
3
For full terms and conditions, visit www.baxi.co.uk/terms. Failure to adhere to
terms and conditions will void your manufacturer’s warranty.
Baxi
Brooks House,
Coventry Road,
Warwick, CV34 4LL
Please ensure the boiler is installed in accordance with these installation
instructions and that you adhere to the Building Regulations.
e&oe
All descriptions and illustrations provided in this document have been
carefully prepared but we reserve the right to make changes and
improvements in our products which may affect the accuracy of the
information contained in this leaflet. All goods are sold subject to our
standard Conditions of Sale which are available on request.