Baxi Duo-tec Combi 24 HE A Release note

Please leave these instructions with the user
Baxi Platinum Combi HE Range
Gas Fired Wall Mounted Condensing
Combination Boiler
Installation & Servicing Instructions

2
Natural Gas
Baxi Platinum Combi 24 HE
G.C.No47 075 20
Baxi Platinum Combi 28 HE
G.C.No47 075 21
Baxi Platinum Combi 33 HE
G.C.No47 075 22
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. From 1 April 2005 this
can be achieved via a Competent Persons Self Certification
Scheme as an option to notifying the Local Authority directly.
Similar arrangements will follow for Scotland and will apply in
Northern Ireland from 1 January 2006.
CORGI operate a Self Certification Scheme for gas heating
appliances.
These arrangements represent a change from the situation
whereby compliance with Building Regulations was accepted as
being demonstrated by completion of the Benchmark Logbook
(which was then left on site with the customer).
With the introduction of Self Certification Schemes, the
Benchmark Logbook is being withdrawn. However, a similar
document in the form of a commissioning checklist and service
interval record is incorporated at the back of these instructions.
Baxi 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.
Baxi is a BS-EN ISO 9001
Accredited Company
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 0085.
Product/Production certified by:
Notified Body 0085.
For GB/IE only.

3
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
CORGI will record the data and
will send a certificate of
compliance to the property
You must ensure that the
notification number issued by
CORGI is writen onto the
Benchmark Checklist
Scheme Members only
Call CORGI on: 0870 88 88 777
or log onto:
www.corgi-notify.com
within 10 days
If you notify via CORGI Scheme,
CORGI will then notify the
relevant Local Authority
Building Control Scheme
on member's behalf
Complete the
Benchmark Checklist
Install and Commission this
appliance to manufacturer's
instructions
Competent Person's
Self Certification Scheme Building Control

4
Legislation
Codes of Practice - refer to the most recent version
IMPORTANT - Installation, Commissioning, Service & Repair
This appliance must be installed in accordance with the manufacturer’s instructions and
the regulations in force. 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.
Definition of competence: A person who works for a CORGI 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”.
Lifting - This product should be lifted and handled by two people. Stooping should be
avoided and protective equipment worn where necessary. Carrying & lifting equipment
should be used as required, e.g. when installing in a loft space.
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.
Warning - Check the information on the data plate is compatible with local supply
conditions.
All CORGI registered installers carry a CORGI identification card and have a
registration number. You can check your installer is registered by telephoning 0870
4012300 or writing to:-
1 Elmwood,
Chineham Business Park,
Crockford Lane,
Basingstoke. RG24 8WG
or check online at www.corgi-gas-safety.com
Baxi declare 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 CORGI
Registered Installer. It must be carried out in accordance with
the relevant requirements of 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.
All systems must be thoroughly flushed and treated with
inhibitor (see section 6.2).
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 5449 Forced circulation hot water 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 5449 Forced circulation hot water systems.
BS 7074 Expansion vessels and ancillary equipment for
sealed water systems.
BS 7593 Treatment of water in domestic hot water
central heating systems.

5
CONTENTS
1.0 Introduction 6
2.0 General Layout 7
3.0 Appliance Operation 8
4.0 Technical Data 9
5.0 Dimensions and Fixings 12
6.0 System Details 13
7.0 Site Requirements 16
8.0 Installation 22
9.0 Commissioning 28
10.0 Completion 31
11.0 Servicing 32
12.0 Changing Components 34
13.0 Combustion Check 43
14.0 Electrical 44
15.0 Short Parts List 45
16.0 Fault Finding 46
17.0 Notes 52
Benchmark Checklist 54
Section Page

6
1.0 Introduction
1.1 Description
1. The Baxi Platinum Combi HE is a fully automatic gas fired
wall mounted condensing combination boiler. It is room sealed
and fan assisted, and will serve central heating and mains fed
domestic hot water.
2. The boiler is set to give a maximum output of :-
24 models - 24 kW DHW
25.9 kW CH (Condensing)
28 models - 28 kW DHW
25.9 kW CH (Condensing)
33 models - 33 kW DHW
30.3 kW CH (Condensing)
3. It is designed for use on Natural Gas (G20).
4. The boiler is suitable for use only on fully pumped sealed
heating systems. Priority is given to domestic hot water.
5. The boiler is supplied with a filling loop and integral timer.
6. The boiler data badge gives details of the model, serial
number and Gas Council number and is situated on the inner
door panel. It is visible when the case front panel is removed
(Fig. 1).
7. The boiler model name and serial number are also shown
on the information label on the iner face of the right hand
case panel. This is for user reference.
8. The boiler is intended to be installed in residential /
commercial / light industrial E.M.C. environments on a
governed meter supply only.
9. The boiler must be installed with one of the purpose
designed flues such as the standard horizontal flue kit, part no.
5111073.
10. All systems must be thoroughly flushed and treated with
inhibitor (see section 6.2).
1.2 Optional Extras
Various flue extensions, bends, vertical flue kits, control
accessories etc. are available as optional extras. These are
detailed in a separate publication.
NOTE: All illustrations show the Platinum Combi 24 HE
unless otherwise stated.
Fig. 1
Control Box
Case Front Panel
Data Badge
Information
Label

7
2.0 General Layout
2.1 Layout
1. Expansion Vessel
2. Automatic Air Vent
3. DHW Plate Heat Exchanger
4. Circulation Pump
5. Drain Off Point
6. Pressure Relief Valve
7. Integral Timer Position
8. Central Heating System Pressure Gauge
9. PCB
10. Control Box
11. 3-Way Valve Assembly
12. Condensate Trap
13. Flame Sensing Electrode
14. Spark Electrode
15. Primary Heat Exchanger
16. Fan Assembly
17. On/Off/Reset Selector Switch
18. Central Heating Temperature Control
19. Hot Water Temperature Control
20. Venturi
21. Air/Gas Collector
22. Combustion Box Cover & Burner
23. Igniter
24. Burner On Light
25. Central Heating Mode Light
26. Domestic Hot Water Mode Light
27. Display
1
17 18 19 87
2
1
0
4
3
bar
1
2
3
4
5
PM
7
8
9
10
11
12
1
2
3
4
5
AM
7
8
9
10
11
12
GRASSLIN
0
22
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
20
21
23
24
25 26
27

8
3.0 Appliance Operation
3.1 Central Heating Mode (Fig. 2)
1. With a demand for heating, the pump circulates water
through the primary circuit.
2. Once main burner ignites the fan speed controls the gas
rate to maintain the heating temperature measured by the
temperature sensor.
3. When the flow temperature exceeds the setting
temperature, a 3 minute delay occurs before the burner
relights automatically (anti-cycling). The pump continues to
run during this period.
4. When the demand is satisfied the burner is extinguished
and the pump continues to run for a period of 3 minutes
(Pump Overrun).
3.2 Domestic Hot Water Mode (Fig. 3)
1. Priority is given to the domestic hot water supply. A
demand at a tap or shower will override any central heating
requirement.
2. The flow of water will operate the Hall Effect Sensor
which requests the 3 way valve to change position. This will
allow the pump to circulate the primary water through the
DHW plate heat exchanger.
3. The burner will light automatically and the temperature of
the domestic hot water is controlled by the temperature
sensor.
4. When the domestic hot water demand ceases the burner
will extinguish and the diverter valve will remain in the
domestic hot water mode, unless there is a demand for
central heating.
IMPORTANT: When the selector switch is in the ‘0’
(Off) position the electrical supply to the boiler is isolated.
The boiler will not operate and the integral timer will
require resetting once the selector switch is set to either
Position (i) or Position (ii).
3.3 Frost Protection Mode
1. The frost protection mode is integral to the appliance and
functions only with the selector switch (see Section 2.1) in
the domestic hot water and central heating position. If the
system temperature falls below 5° C then the boiler will fire
on its minimum setting until a flow temperature of 30° C is
reached. Further protection can be incorporated by using a
system frost thermostat.
3.4 Pump Protection
1. With the selector switch (see Section 2.1) in either the
central heating or central heating and domestic hot water
position, the pump will automatically operate for 1 minute in
every 24 hours to prevent sticking.
1
2
4
5 6
7
8
9
10
11
1213141516
17
18
19
21
22
24
25
26
3
1 Primary Heat Exchanger
2 Burner
3 Ignition Electrode
4 Flame Sensing Electrode
5 Gas Valve
6 Pump
7 Automatic Air Vent
8 Plate Heat Exchanger
9 Flow Sensor with Filter & Regulator
10 Pressure Relief Valve
11 Boiler Drain Point
12 Heating Return
13 Cold Water Inlet On/Off Valve and Filter
14 Gas Inlet
15 Domestic Hot Water Outlet
16 Heating Flow
17 Pressure Gauge
18 Water Pressure Sensor
19 Automatic By-Pass
20 Fan
21 Diverter Valve Assembly
22 Diverter Valve Motor
23 Domestic Hot Water Flow Temperature Sensor
24 Safety Thermostat
25 Central Heating Temperature Sensor
26 Expansion Vessel
Key
Central Heating Circuit
Domestic Hot Water Circuit
Fig. 3
1
2
4
5 6
7
8
9
10
11
1213141516
17
18
19
21
22
24
25
26
3
Fig. 2
23
23
20
20

9
4.0 Technical Data
4.1 Platinum Combi 24 HE
Flue Terminal Diameter 100mm
Dimensions Projection 125mm
Outercase Dimensions
Casing Height - 780mm
Overall Height Inc Flue
Elbow - 965mm
Casing Width - 450mm
Casing Depth - 345mm
Weights kg
Packaged Boiler Carton 56.5
Installation Lift Weight 45
Central Heating Primary Circuit
Pressures
bar
Safety Discharge 3
Max Operating 2.5
Min Operating 0.5
Recommended Operating Range 1-2
DHW Circuit bar
Pressures
Max Operating 8
Min Operating 0.15
Flow Rates l/min
DHW Flow Rate
@ 30o C Rise 11.43
DHW Flow Rate
@ 35o C Rise 9.8
Min Working
DHW Flow Rate 2
Pump
Available Head See graph below
Expansion Vessel - (For Central Heating
only. Integral with appliance)
bar
Min Pre-charge Pressure 0.5
litre
Max Capacity of
CH System 125
Primary Water Content
of Boiler (unpressurised) 2.5
Connections copper tails
Gas Supply - 22mm
Central Heating Flow - 22mm
Central Heating Return - 22mm
Cold Water Mains Inlet - 15mm
DHW Flow - 15mm
Pressure Relief Discharge - 15mm
Temperatures
C.H. Flow Temp (adjustable)
25°C to 80°C max (± 5°C)
D.H.W. Flow Temp (adjustable)
35°C to 60°C max (± 5°C)
dependent upon flow rate
NOxClass 5
0
200 400 600 800 1000 1200
0.5
1
1.5
2
2.5
3
3.5
4
Metre (wg)
Flow Rate (l/h)
Pump - Available Head
0
5
5.5
4.5
Clearances
Above Casing 200 mm Min
Below Casing 200 mm Min
Front 450 mm Min (For Servicing)
Front 5 mm Min (In Operation)
L.H. Side 5 mm Min
R.H. Side 5 mm Min (In Operation)
Heat Input CH (Net)
Max Min
kW 24.7 7
Heat Output CH (Non-Condensing)
Max Min
kW 24 6.8
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption 155W
Electrical Protection IPX0D
Internal Fuse Rating
F2L
Appliance Category CAT I 2H
Inlet Pressure (Natural Gas - G20)
mbar 20
Injector (Natural Gas - G20)
7.5mm
Appliance Type C13 C33
Heat Output CH (Condensing)
Max Min
kW 25.9 7.4
Heat Input DHW (Net)
Max
kW 24.7
Heat Output DHW
Max
kW 24
Max Gas Rate (Natural Gas - G20)
(After 10 mins)
m3/h 2.61
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 have been certified by 0085.
SEDBUK Declaration For Platinum 24 HE
The seasonal efficiency (SEDBUK) is 90.1%
Band A
Condensate Drain
To accept 21.5mm (3/4in) plastic waste pipe
Heat Input CH (Gross)
Max Min
kW 27.4 7.8
Heat Input DHW (Gross)
Max
kW 27.4
External Fuse Rating 3A

10
4.0 Technical Data
4.2 Platinum Combi 28 HE
Flue Terminal Diameter 100mm
Dimensions Projection 125mm
Outercase Dimensions
Casing Height - 780mm
Overall Height Inc Flue
Elbow - 965mm
Casing Width - 450mm
Casing Depth - 345mm
Weights kg
Packaged Boiler Carton 56.5
Installation Lift Weight 45
Central Heating Primary Circuit
Pressures
bar
Safety Discharge 3
Max Operating 2.5
Min Operating 0.5
Recommended Operating Range 1-2
DHW Circuit bar
Pressures
Max Operating 8
Min Operating 0.15
Flow Rates l/min
DHW Flow Rate
@ 30o C Rise 13.3
DHW Flow Rate
@ 35o C Rise 11.5
Min Working
DHW Flow Rate 2
Pump
Available Head See graph below
Expansion Vessel - (For Central Heating
only. Integral with appliance)
bar
Min Pre-charge Pressure 0.5
litre
Max Capacity of
CH System 125
Primary Water Content
of Boiler (unpressurised) 2.5
Connections copper tails
Gas Supply - 22mm
Central Heating Flow - 22mm
Central Heating Return - 22mm
Cold Water Mains Inlet - 15mm
DHW Flow - 15mm
Pressure Relief Discharge - 15mm
Temperatures
C.H. Flow Temp (adjustable)
25°C to 80°C max (± 5°C)
D.H.W. Flow Temp (adjustable)
35°C to 60°C max (± 5°C)
dependent upon flow rate
NOxClass 5
0
200 400 600 800 1000 1200
0.5
1
1.5
2
2.5
3
3.5
4
Metre (wg)
Flow Rate (l/h)
Pump - Available Head
0
5
5.5
4.5
Clearances
Above Casing 200 mm Min
Below Casing 200 mm Min
Front 450 mm Min (For Servicing)
Front 5 mm Min (In Operation)
L.H. Side 5 mm Min
R.H. Side 5 mm Min (In Operation)
Heat Input CH (Net)
Max Min
kW 24.7 9
Heat Output CH (Non-Condensing)
Max Min
kW 24 8.7
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption 155W
Electrical Protection IPX0D
Internal Fuse Rating
F2L
Appliance Category CAT I 2H
Inlet Pressure (Natural Gas - G20)
mbar 20
Injector (Natural Gas - G20)
7.5mm
Appliance Type C13 C33
Heat Output CH (Condensing)
Max Min
kW 25.9 9.5
Heat Input DHW (Net)
Max
kW 28.9
Heat Output DHW
Max
kW 28
Max Gas Rate (Natural Gas - G20)
(After 10 mins)
m3/h 3.1
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 have been certified by 0085.
SEDBUK Declaration For Platinum 24 HE
The seasonal efficiency (SEDBUK) is 90.1%
Band A
Condensate Drain
To accept 21.5mm (3/4in) plastic waste pipe
Heat Input CH (Gross)
Max Min
kW 27.4 10
Heat Input DHW (Gross)
Max
kW 32.1
External Fuse Rating 3A