Baxi Combi 80e User guide

Baxi Combi 80e & 105e
Gas Fired Wall Mounted Combination Boiler
Installation and
Servicing Instructions
Please leave these instructions with the user
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Baxi UK Limited is one of the leading manufacturers
of domestic heating products in the UK.
Our first priority is to give a high quality service to our
customers. Quality is designed into every Baxi product
- products which fulfil the demands and needs of
customers, offering choice, efficiency and reliability.
To keep ahead of changing trends, we have made a
commitment to develop new ideas using the
latest technology - with the aim of continuing to make
the products that customers want to buy.
Everyone who works at Baxi has a commitment to
quality because we know that satisfied customers
mean continued success.
We hope you get a satisfactory service from Baxi. If
not, please let us know.
Natural Gas
Baxi Combi 80e
G.C.No47 075 06
Baxi Combi 105e
G.C.No47 075 08
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 0051.
Product/Production certified by:
Notified Body 0051.
For GB/IE only.

3
1.0 Introduction 4
2.0 General Layout 5
3.0 Appliance Operation 6
4.0 Technical Data 7
5.0 Dimensions and Fixings 9
6.0 System Details 10
7.0 Site Requirements 13
8.0 Installation 18
9.0 Commissioning the Boiler 23
10.0 Completion 25
11.0 Servicing the Boiler 26
12.0 Changing Components 28
13.0 Illustrated Wiring Diagram 37
14.0 Fault Finding 38
15.0 Short Parts List 43
Section Page
Contents

Baxi UK Limited declare that no substances
harmful to health are contained in the
appliance or used during appliance
manufacture.
1.1 Description
1. The Baxi Combi 80e or 105e is a fully automatic
gas fired wall mounted 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
24.0 kW (80e) or 31.0 kW (105e).
3. It is designed for use on Natural Gas (G20) and
can be converted to use Propane (80e and 105e)
or Butane (80e).
4. The boiler is suitable for use only on fully
pumped sealed heating systems. Priority is given
to domestic hot water.
5. The boiler data badge gives details of the
model, serial number and Gas Council number
and is situated on the control box. It is visible when
the case front panel is removed (Fig. 1).
6. The boiler is intended to be installed in
residential / commercial / light industrial E.M.C.
environments on a governed meter supply only.
7. The boiler must be installed with one of the
purpose designed flues such as the standard
horizontal flue kit, part no. 247719.
8. All systems must be thoroughly flushed and
treated with inhibitor (see section 6.2).
1.2 Installation
1. The appliance is suitable for installation only in G.B. and
I.E. and should be installed in accordance with the rules in
force. For Ireland install in accordance with I.S.813
“INSTALLATION OF GAS APPLIANCES”. The installation must be
carried out by a CORGI Registered Installer or other
competent person and be in accordance with the relevant
requirements of GAS SAFETY (Installation and Use)
REGULATIONS, the BUILDING REGULATIONS (Scotland)
(Consolidation), the LOCAL BUILDING REGULATIONS, the
CURRENT I.E.E. WIRING REGULATIONS and the bye laws of the
Local Water Undertaking. Where no specific instructions are
given, reference should be made to the relevant BRITISH
STANDARD CODES OF PRACTICE.
1.3 Optional Extras
Various flue extensions, bends, vertical flue kits,
control accessories etc. are available as
optional extras. These are detailed in a
separate publication.
1.0 Introduction
4
Data Badge
Fig. 1
Control Box
“Benchmark”Log Book
As part of the industry-wide “Benchmark”initiative all Baxi boilers now
include an Installation, Commissioning and Service Record Log Book.
Please read the Log Book carefully and complete all sections relevant to
the appliance and installation. These include sections on the type of
controls employed, flushing the system, burner operating pressure etc.
The details of the Log Book will be required in the event of any warranty
work. Also, there is a section to be completed at each subsequent regular
service visit. The Log Book must be left with the user.
Case Front Panel
NOTE: 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.

2.0 General Layout
5
2.1 Layout
1. Air Pressure Switch
2. Expansion Vessel
3. Burner Manifold
4. Automatic Air Vent
5. DHW Plate Heat Exchanger
6. Circulation Pump
7. Drain Off Point
8. Pressure Relief Valve
9. Optional Integral Timer
10. Central Heating System Pressure Gauge
11. PCB
12. Control Box
13. 3-Way Valve Assembly
14. Spark Generator
15. Flame Sensing Electrode
16. Spark Electrode
17. Burner
18. Primary Heat Exchanger
19. Fan Assembly
20. On/Off/Reset Selector Switch
21. Central Heating Temperature Control
22. Hot Water Temperature Control
23. Flame Failure
24. Safety Thermostat
25. Fault on Fan or Flue
26. Fault on Pump or Low System Pressure
27. Fault on Hot Water Sensor
28. Fault on Central Heating Sensor
29. Power On
30. Domestic Hot Water Mode
31. Central Heating Mode
32. Burner On
When neons 23 to 28 are constantly illuminated,
they indicate the temperature of the central heating
water.
19
18
17
14
15
16
13
12 11
10 9
20 21 22 10 9
7
6
3
4
5
8
2
1
30°40°50°60°70°80°
2
1
0
4
3
bar
30°40°50°60°70°80°
23 24 25 26 27 28
29 30 31 32

3.0 Appliance Operation
6
NOTE: All delay timers mentioned in 3.1 and 3.2
are overridden by domestic hot water demand.
3.1 Central Heating Mode (Fig. 2)
1. With a demand for heating, the pump circulates
water through the primary circuit. At a pre-
determined flow rate the central heating flow
switch operates, initiating the ignition sequence.
2. The main burner ignites at low rate, then the
gas valve 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 30 seconds (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 DHW flow
switch 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 (if fitted) 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
20
21
22
23
24
25
26
3
1 Primary Heat Exchanger
2 Burner
3 Ignition Electrode
4 Flame Sensing Electrode
5 Gas Valve
6Pump
7 Automatic Air Vent
8 Plate Heat Exchanger
9 Flow Sensor with Filter
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 Hydraulic Differential Pressure Sensor Microswitch
19 Automatic By-Pass
20 Hydraulic Differential Pressure Sensor
21 Diverter Valve Assembly
22 Domestic Hot Water Flow Priority Assembly
23 Domestic Hot Water Flow Priority Microswitch
24 Safety Thermostat
25 Central Heating Temperature Sensor
26 Expansion Vessel
27 Domestic Hot Water Temperature Sensor
Key
Central Heating Circuit
Domestic Hot Water Circuit
Fig. 3
1
2
4
5 6
7
8
9
10
11
1213141516
17
18
19
20
21
22
23
24
25
26
3
Fig. 2
27
27

4.0 Technical Data
7
Flue Terminal Diameter 100mm
Dimensions Projection 95mm
Outercase Dimensions
Casing Height - 780mm
Overall Height Inc Flue
Elbow - 980mm
Casing Width - 450mm
Casing Depth - 345mm
Clearances
Both Sides 5 mm Min
Above Casing 200 mm Min
Below Casing 200 mm Min
Front 450 mm Min (For Servicing)
Front 5 mm Min (In Operation)
Weights kg
Packaged Boiler Carton 47
Packaged Flue Kit 3
Installation Lift Weight 39
Central Heating Primary Circuit
Pressures
bar
Safety Discharge 3
Max Operating 2.5
Min Operating 0.5
Recommend Operating 1-2
DHW Circuit bar
Pressures
Max Operating 8
Min Operating 0.2
Min Operating Pressure
at 9.8 l/min 0.9
Flow Rates l/min
DHW Flow Rate
@ 30°C Rise 13.7
DHW Flow Rate
@ 35°C Rise 9.8
Min Working
DHW Flow Rate 2.5
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 1.0
of Boiler (unpressurised)
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
Recommended System
Temperature Drop 11°C20°F
Temperatures
C.H. Flow Temp (adjustable)
35°C to 85°C max (± 5°C)
D.H.W. Flow Temp (adjustable)
35°C to 65°C max (± 5°C)
dependent upon flow rate
Heat Input C/H & DHW (Gross)
Max Min
kW 26.3 10.6
Btu/h 89,739 31,738
Heat Output Max Min
kW 24.0 9.3
Btu/h 81,891 31,738
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption 170W
External Fuse Rating 3A
Internal Fuse Rating
Fuse 2A Fast Blow to BS 4265
Appliance Category CAT II 2H 3+
Max Gas Rate (Natural Gas - G20)
(After 10 Mins)
m3/h 2.78
ft3/h 98.12
Inlet Pressure (Natural Gas - G20)
mbar 20
in wg 8
Burner Injector (Natural Gas - G20)
12 x 1.28mm Diameter
Burner Pressure (Natural Gas - G20)
Max Rate Min Rate
mbar 12.2 ± 0.5 2.5 ± 0.2
in wg 4.88 ± 0.2 1.0 ± 0.2
0
200 400 600 800 1000 1200
0.5
1
1.5
2
2.5
3
3.5
4
Metre wg
l/h
Pump - Available Head
0
Appliance Type C12 C32 NOxClass 3
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 0051.
SEDBUK Declaration For Combi 80e
The seasonal efficiency (SEDBUK) is 78.6 %
Electrical Protection
IPX5D
4.1 Combi 80e
LPG Gases Propane - G31 and
Butane - G30
Burner Injector 12 x 0.77mm diameter
Burner Pressure
Propane mbar
in wg
Butane mbar
in wg
Inlet Pressures
mbar
in wg
Max Rate
36.2
14.5
28.3
11.3
Min Rate
6.4
2.6
5.3
2.1
Propane
37
14.8
Butane
28
11.2

4.0 Technical Data
8
4.2 Combi 105e
Flue Terminal Diameter 100mm
Dimensions Projection 95mm
Outercase Dimensions
Casing Height - 780mm
Overall Height Inc Flue
Elbow - 980mm
Casing Width - 450mm
Casing Depth - 345mm
Clearances
Both Sides 5 mm Min
Above Casing 200 mm Min
Below Casing 200 mm Min
Front 450 mm Min (For Servicing)
Front 5 mm Min (In Operation)
Weights kg
Packaged Boiler Carton 49
Packaged Flue Kit 3
Installation Lift Weight 41
Central Heating Primary Circuit
Pressures
bar
Safety Discharge 3
Max Operating 2.5
Min Operating 0.5
Recommend Operating 1-2
DHW Circuit bar
Pressures
Max Operating 8
Min Operating 0.2
Min Operating Pressure
at 12.7 l/min 0.96
Flow Rates l/min
DHW Flow Rate
@ 30°C Rise 14.8
DHW Flow Rate
@ 35°C Rise 12.7
Min Working
DHW Flow Rate 2.5
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 1.2
of Boiler (unpressurised)
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
Recommended System
Temperature Drop 11°C20°F
Temperatures
C.H. Flow Temp (adjustable)
35°C to 85°C max (± 5°C)
D.H.W. Flow Temp (adjustable)
35°C to 65°C max (± 5°C)
dependent upon flow rate
Heat Input C/H & DHW (Gross)
Max Min
kW 34.3 11.9
Btu/h 117,036 40,610
Heat Output Max Min
kW 31.0 10.4
Btu/h 105,776 35,490
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption 190W
External Fuse Rating 3A
Internal Fuse Rating
Fuse 2A Fast Blow to BS 4265
Appliance Category CAT II 2H 3P
Max Gas Rate (Natural Gas - G20)
(After 10 Mins)
m3/h 3.63
ft3/h 128.12
Inlet Pressure (Natural Gas - G20)
mbar 20
in wg 8
Burner Injector (Natural Gas - G20)
15 x 1.28mm Diameter
Burner Pressure (Natural Gas - G20)
Max Rate Min Rate
mbar 13.4 ± 0.5 1.8 ± 0.2
in wg 5.36 ± 0.2 0.72 ± 0.2
Appliance Type C12 C32 NOxClass 3
Electrical Protection
IPX5D
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 0051.
SEDBUK Declaration For Combi 105e
The seasonal efficiency (SEDBUK) is 78.5 %
0
200 400 600 800 1000 1200
0.5
1
1.5
2
2.5
3
3.5
4
Metre wg
l/h
Pump - Available Head
0
5
4.5
LPG Gases Propane - G31
Burner Injector 15 x 0.77mm diameter
Burner Pressure
Propane mbar
in wg
Inlet Pressures
mbar
in wg
Max Rate
36.2
14.5
Min Rate
6.4
2.6
37

5.0 Dimensions and Fixings
9
Dimensions
A780mm
B345mm
C450mm
D107mm ØMin.
E200mm
F190mm
G143mm
360°Orientation
Tube Ø100mm
DC
B
A
E
G
F
Domestic Hot
Water Outlet
(15mm)
Cold Water
Inlet
(15mm)
Heating
Return
(22mm)
Heating
Flow
(22mm)
Pressure Relief
Valve
(15mm)
Gas
Inlet
(22mm)
65 mm 65 mm 65 mm 65 mm 65 mm
Tap Rail

6.0 System Details
10
6.1 Information
1. The Baxi Combi 80e and 105e Combination Boilers
are ‘Water Byelaws Scheme - Approved Products’.
To comply with the Water Byelaws your attention is
drawn to the following installation requirements and
notes (IRN).
a) IRN 001 - See text of entry for installation
requirements and notes.
b) IRN 302 - Byelaw 14.
2. Reference to the WRc publications, ‘Water fittings
and materials directory’and ‘Water supply byelaws
guide’give full details of byelaws and the IRNs.
6.2 Central Heating Circuit
1. The appliance is suitable for fully pumped SEALED
SYSTEMS ONLY.
Treatment of Water Circulating Systems
•All recirculatory water systems will be subject to
corrosion unless an appropriate water treatment is
applied. This means that the efficiency of the system
will deteriorate as corrosion sludge accumulates
within the system, risking damage to pump and
valves, boiler noise and circulation problems.
•For optimum performance after installation this
boiler and its associated central heating system must
be flushed in accordance with the guidelines given in
BS 7593 “Treatment of water in domestic hot water
central heating systems”.
•This must involve the use of a proprietary cleanser,
such as BetzDearborn Sentinel X300 or X400, or
Fernox Superfloc. Full instructions are supplied with
the products, but for immediate information please
contact BetzDearborn (0151 420 9563) or Fernox
(01799 550 811) directly.
•For long term protection against corrosion and
scale, after flushing it is recommended that an
inhibitor such as BetzDearborn Sentinel X100, or
Fernox MB-1 or Copal is dosed in accordance with
the guidelines given in BS 7593.
Failure to flush and add inhibitor to the system
may invalidate the appliance warranty.
•It is important to check the inhibitor concentration
after installation, system modification and at every
service in accordance with the manufacturer’s
instructions. (Test kits are available from inhibitor
stockists.)
•For information or advice regarding any of the
above contact the Baxi Helpline.
6.3 Bypass
1. The boiler is fitted with an automatic integral
bypass.
6.4 System Control
1. The boiler is designed for use in a heating
system that incorporates external controls, i.e. a
minimum of a timer device.
2. Suitable timer kits are available as optional
extras.
3. For optimum operating conditions and maximum
economy the fitting of a programmable room
thermostat, such as the Baxi Combi Controller, is
recommended.