Baxi System 100 HE Plus Release note

Please leave these instructions with the user
Baxi System 100 HE Plus
Wall Mounted Powered Flue Condensing
Gas Fired Central Heating Boiler
Installation & Servicing Instructions

2
Natural Gas
Baxi System 100 HE Plus
G.C.No1 075 3
The boiler meets the requirements of Statutory Instrument “
The Boiler (Efficiency) Regulations 1993 No3083” and is
deemed to meet the requirements of Directive 92/ 2/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 0087.
Product/Production certified by:
Notified Body 0086.
For GB/IE only.
Baxi is a BS-EN ISO 9001
Accredited Company
This product has an energy rating (A) on a scale of A to G.
For more information see www.boilers.org.uk. This is a certification mark.
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Benchmark Logbook is being withdrawn.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.
Potterton 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.

Installer Noti ication Guidelines
3
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

Legislation
Codes o Practice, most recent version should be used
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.
De inition o 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”.
Li ting - This product should be lifted and handled by two people. For recommended
hand holds see section 8. . 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.
Baxi declare that no substances harm ul to health are
contained in the appliance or used during appliance
manu acture.
The appliance is suitable only or installation in GB and IE and
should be installed in accordance with the rules in orce, 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 lushed and treated with
inhibitor (see section 6.2).
In GB the ollowing Codes o Practice apply:
Standard Scope
BS 6891 Gas Installation.
BS 55 6 Installation of hot water supplies for domestic
purposes.
BS 5 9 Forced circulation hot water systems.
BS 6798 Installation of gas fired hot water boilers.
BS 5 0 Part 1 Flues.
BS 5 0 Part 2 Ventilation.
BS 707 Expansion vessels and ancillary equipment for
sealed water systems.
BS 7593 Treatment of water in domestic hot water
central heating systems.
In IE the ollowing Codes o Practice apply:
Standard Scope
I.S. 813 Domestic Gas Installations.
The following BS standards give valuable additional information;
BS 55 6 Installation of hot water supplies for domestic
purposes.
BS 5 9 Forced circulation hot water systems.
BS 707 Expansion vessels and ancillary equipment for
sealed water systems.
BS 7593 Treatment of water in domestic hot water
central heating systems.
All CORGI registered installers carry a CORGI identification card and have a
registration number. You can check your installer is registered by telephoning
0870 012300 or writing to:-
1 Elmwood,
Chineham Business Park,
Crockford Lane,
Basingstoke. RG2 8WG
or check online at www.corgi-gas-safety.com

5
1.0 Introduction 6
2.0 General Layout 7
3.0 Appliance Operation 8
4.0 Technical Data 9
5.0 Dimensions and Fixings 10
6.0 System Details 11
7.0 Site Requirements 1
8.0 Installation 20
9.0 Electrical 26
10.0 Commissioning 28
11.0 Outer Case 29
12.0 Servicing 30
13.0 Changing Components 32
14.0 Short Parts List 1
15.0 Fault Finding 2
Benchmark Checklist 50
Section Page
Contents

1.0 Introduction
6
1.1 Description
1. The Baxi System 100 HE Plus is a gas fired room sealed fan
assisted condensing central heating system boiler.
2. The maximum output of the boiler is preset at 75,000
Btu/hr. The boiler will automatically adjust down to 30,000
Btu/hr according to the system load. If required, the output
can be set to 100,000 Btu/hr. Please refer to section 8.7.
3. It is designed for use on Natural Gas (G20).
. The boiler is suitable for sealed central heating and
domestic hot water systems.
5. A label giving details of the model, serial number and Gas
Council number is situated on the rear of the lower door
panel (Fig. 1).
6. The boiler data badge is positioned on the air box door
(Fig. 2).
7. The boiler is intended to be installed in residential /
commercial / light industrial E.M.C. environments on a
governed meter supply only.
8. The boiler must be installed with one of the purpose
designed flues such as the standard horizontal flue kit, part no
236921.
1.2 Important In ormation
Man-made mineral ibre
• Some component parts of this appliance (insulation pads,
gaskets and rope seals) are manufactured from man-made
mineral fibre.
• Prolonged or excessive exposure to this material may
result in some irritation to the eyes, skin or respiratory tract.
• It is advisable to wear gloves when handling these items.
• Irritant dust will only be released from the items if they are
broken up or subjected to severe abrasion. In these instances
a suitable dust mask and goggles should be worn.
• Always thoroughly wash hands after installation, servicing or
changing components.
• When disposing of any items manufactured from man-
made mineral fibre care must be exercised.
• If any irritation of the eyes or severe irritation of the skin is
experienced seek medical attention.
NOTE: All illustrations show the PCB Connection
Cover removed unless otherwise shown.
Fig. 1
Data Badge
Air Box Door
Lower Door Panel
Fig. 2
Label

2.0 General Layout
7
2.1 Layout (Figs. 3, & 5)
1. Wall Plate
2. Flue Elbow
3. Heat Exchanger
. Burner
5. Air Box
6. Fan Protection Thermostat
7. Fan Assembly
8. Condensate Trap
9. Gas Tap
10. Gas / Air Ratio Valve
13. Flow Temperature Safety Thermostat - Black
1 . Flow Temperature Thermistor - Red
15. Flow Switch (dry fire protection)
16. Circulation Pump
17. Manual Air Vent
18. Pressure Relief Valve
19. Water Pressure Gauge
20. Expansion Vessel
1
2
3
4
5
6
7
8
9
10
13/14
17
16
Fig. 4
Fig. 3
Fig. 5
15
18
19
20
Fig. 6
2.2 Optional Extras
KIT PART No
FLUE EXTENSION KITS (110/70)
Flue Extension 0.25M 2 1692
Flue Extension 0.5M 2 169
Flue Extension 1M (Use two kits for 2M etc.) 2 1695
Flue Bend x 2 - 5° (Reduce overall length of flue
by 0.5m when fitting this bend) 2 1689
Flue Bend - 90° (Reduce overall length of flue
by 1m when fitting each bend) 2 1687
Horizontal Extended Flue (1.75M) 5111 57
VERTICAL FLUE (110/70)
Vertical Flue Terminal 2 2802
Vertical Flue Adaptor 5106888
VERTICAL FLUE (80/80)
Kit Boiler Connection Twin 2 2757

3.0 Appliance Operation
8
3.1
1. Switched Live To Boiler On: When the switched live
switches on if the flow temperature is less than the set
point then pump on occurs. When the switched live to
the boiler switches on if the flow temperature is greater
than the set point then pump overrun occurs.
2. Pump On: The pump is on while the fan, spark
generator and gas valve are off. After 10 seconds if the
flow switch has made then fan pre-purge occurs. After
10 seconds if the flow switch has not made then anti-
cycle occurs.
3. Fan Pre-Purge: The pump and fan are on while the
spark generator and gas valve are off. After 5 seconds
ignition occurs.
. Ignition: The pump, fan, spark generator and gas
valve are on. If a flame is detected then burner on
occurs. If a flame is not detected within 5 seconds and
less than 5 ignition attempts have been made then fan
purge occurs. If a flame is not detected within 5 seconds
and 5 ignition attempts have been made then ignition
lockout occurs.
5. Burner On: The pump, fan and gas valve are on while
the spark generator is off. Flow temperature is
controlled by varying the fan speed (and thereby the
gas rate) to achieve optimum operation. If the flow
temperature is greater than the set point then pump
overrun occurs. If the TRVs all shut down then anti-
cycle occurs.
6. Pump Overrun: The pump is on while the fan, spark
generator and gas valve are off. After 1 minute anti-
cycle occurs.
7. Anti-cycle: The pump, fan, spark generator and gas
valve are off. After 3 minutes if the flow temperature is
less than the set point then pump on occurs. After 3
minutes if the flow temperature is greater than the set
point then pump overrun occurs.
8. Ignition Lockout: The pump, fan, spark generator and
gas valve are off. The boiler can only be reset by
manually using the reset button.
Switched Live
to Boiler On.
Flow
temperature less
than set point ?
YES
5 second
Fan Pre-Purge.
Flame Detected ?
Burner On.
Ignition
Lockout.
5 second
Ignition Period.
All TRVs
shut down ?
Ignition done and
5 attempts made ?
Ignition done
and less than 5
attempts made ?
Flow switch made ?
NO
YES
YES
YES
10 second
Pump On.
1 minute
Pump Overrun.
3 minute
Anti-cycle.
NO
YES
YES
NO

4.0 Technical Data
9
Appliance Category CAT I 2H
Horizontal
Flue Terminal Diameter 110mm
Dimensions Projection 150mm
Outercase Dimensions
Overall Height Inc Flue Elbow - 1000mm
Casing Height - 850mm
Casing Width - 90mm
Casing Depth - 320mm
Weights kg lb
Packaged Boiler Carton 53.6 118
Packaged Flue Kit 3.6 8.0
Weight Empty 8.6 107
Installation Lift Weight 0.2 88.6
Connections compression
Gas Supply - 1/2” BSPF
Central Heating Flow - 22mm
Central Heating Return - 22mm
Pressure Relief Discharge - 15mm
Condensate Drain - 1” BSP
Recommended System
Temperature Drop
Condensing 20°C 36°F
Heat Input Gross Max Min
kW 33.76 10.2
Btu/h 115,200 3 ,8 0
Heat Output
(Non Condensing 70° C Mean Water Temp)
Max Min
kW 30.18 9.1
Btu/h 102,980 31,180
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption 200W
External Fuse Rating 3A
Internal Fuse Rating (BS 265)
Fuse 3.15 AT (PCB)
Inlet Pressure (Natural Gas)
Min 18.1 mbar
Max 22.5 mbar
(see Section 10.1)
Injector (Natural Gas)
6.3mm Diameter
Clearances
(For unventilated compartments see Section 7.2)
Both Sides 5mm Min
Above Casing 200mm Min
Below Casing 200mm Min
Front (For Servicing) 500mm Min
Front (In Operation) 5mm Min
Appliance Type C13 C33
NoxClass 5
Heat Output
(Condensing 0° C Mean Water Temp)
Max Min
kW 32.61 10.1
Btu/h 111,280 3 ,520
Water Content
litres 3.5
pints 6.2
Controls
boiler thermostat, safety thermostat,
flow switch, electronic flame sensing,
temperature protection thermostat &
condensate blockage sensor.
Central Heating Primary
Circuit Pressures
bar lb/in2
Safety Discharge 3 3.5
Max Operating 2.5 36.3
Min Operating 0.7 10.2
Recommend Operating 1-2 1 .5-29
Expansion Vessel - (For Central Heating only.
Integral with appliance)
bar lb/in2
Min Pre-charge Pressure 0.95 13.6
Nominal Pre-charge
Pressure 1 1 .5
litre gal
Max Capacity of
CH System 125 27.5
0
120 2 0 360 80
100
200
300
00
500
600
Pump Head (mbar)
Flow Rate (l/h)
Central Heating Circuit available Pump Head
0 600 720 8 0
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 0086.
SEDBUK Declaration For
Baxi System 100 HE Plus
The seasonal e iciency (SEDBUK) is 90.9 %
Max Gas Rate (Natural Gas)
(After 10 Mins)
Btu/hr 102,980 75,000
m3/h 2.95 2.36
ft3/h 10 .2 83.3
NOTE: The maximum output of the
boiler is factory set at 22.0kW (75,000
Btu/hr). This can be altered to 30.18kW
(102,980 Btu/hr)
- see section 8.7.
CO/CO2Ratio 0.001
Electrical Protection IPX2

5.0 Dimensions and Fixings
10
DIMENSIONS
A850mm
B320mm
C90mm
D125mm Ø Min.
E150mm
F125mm
SIDE FLUE (le t and right)
For every 1m of horizontal flue
length, the clearance above the top
of the flue elbow should be 55mm to
incorporate the 3°
(1 in 20) fall in the flue from the
terminal to the elbow.
The 3° (1 in 20) fall provided by the
elbow is to allow condensate to run
back to the boiler, for disposal
through the condensate discharge
pipe.
Flue length (Y)
up to 1m
1m - 2m
2m - 3m
Clearance (X)
55mm
110mm
165mm
360° Orientation
Tube Ø 110mm
DC
B
A
E
F
Y
3°
(1 in 20)
X
3°
(1 in 20)
Fig. 7
Fig. 8

6.0 System Details
11
6.1 Water Circulating Systems
1. The appliance is suitable for fully pumped sealed systems
only.
The ollowing conditions should be observed on all systems:
• The boiler must not be used with a direct cylinder.
• Drain cocks should be fitted to all system low points.
• All gas and water pipes and electrical wiring must be installed
in a way which would not restrict the servicing of the boiler.
• Air vents should be fitted to all system high points.
• An air rejection separator is recommended to ensure correct
operation of all appliance components.
2. If the system requires an output from the boiler greater than
75,000 Btu/hr then an additional external pump will need to be
fitted.
3. If the system is fully TRV’d with no bypass then any external
pump can be wired back to the boiler Optional Pump Feed
connection. This will protect the pump by turning it off if all the
TRVs are shut (sensed by the boiler flow switch). This is wired
as in Fig. A. See section 8.7 for how to increase boiler output
from 75.000 Btu/hr to 100,000 Btu/hr.
6.2 Treatment o 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.
• When upgrading existing systems that exhibit evidence of
sludging, it is advisable to clean the system prior to treatment in
order to remove any sludge and reduce the likelihood of these
deposits damaging new components.
• When fitting new systems flux will be evident within the system,
which can lead to damage of system components.
• All systems must be thoroughly drained and flushed out. The
recommended flushing and cleansing agents are Betz-Dearborn
Sentinel X300 or X 00 and Fernox Superfloc Universal Cleanser
which should be used following the flushing agent manufacturer’s
instructions.
• System additives - corrosion inhibitors and flushing
agents/descalers should be suitable for aluminium and comply to
BS7593 requirements. The only system additives recommended
are Betz-Dearborn Sentinel X100 and Fernox-Copal which should
be used following the inhibitor manufacturer’s instructions.
Failure to lush and add inhibitor to the system will 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.
Boiler
Hot water
Central
heating
load
Live feed to
pump
Switch live from
programmer, etc.
S/L N
Optional
Pump
Feed
Fig. A Wiring an extra pump to the pump eed
connection o boiler
Boiler
Connections
S/L N
Filter

6.0 System Details
12
6.3 System Controls
This boiler does not require a bypass.
This boiler does not require a permanent live.
An additional external pump is required i a boiler
output o greater than 75,000 Btu/hr is required.
The additional external pump only needs wiring directly
to the boiler or ully TRV’d systems.
1. To comply with Part L1 of the Building Regulations the
heating system into which the boiler is installed should
include the following:
a) zone controls
b) timing controls
c) boiler control interlocks
2. Such a system needs to be fully pumped and must
provide independent temperature and time control to
both the heating and hot water circuits and have a boiler
interlock.
3. The boiler should be controlled so that it operates on
demand only. Where it is proposed to effect control by
thermostatic radiator valves, a room thermostat (or
other device such as a flow switch - a flow switch is
integral to this boiler) should also be provided to switch
off the boiler when there is no demand for heating or hot
water.
. The interlock for the CH circuit can be provided by
either a Room Thermostat or by a fully TRV’d system
without a bypass. If an external pump is required and the
boiler flow switch is being used as the system interlock
then the additional pump will need to be wired back to
the boiler optional pump feed connection. Connection
diagrams for both options for Y and S plan systems are
shown.
Y Plan
Diverter
Valve
Cylinder
Stat
Room
Stat
Pump
Timer
230V
50Hz
L NE
L
N
CH on
HW on
HW off
LNE
b
g/y w
o
gr
1
C2
Electrical
Filter
LEN
g/y
S Plan
Valve
Cylinder
Stat
Room
Stat
Pump
Timer
230V
50Hz
L NE
L
N
CH on
HW on
LNE
Motor
S Plan
Valve
Motor
o
o
gr
b
g/y
b
gr
br
br
Electrical
Filter
LEN
Y Plan
Diverter
Valve
Cylinder
Stat
Pump
Timer
230V
50Hz
L NE
L
N
CH on
HW on
HW off
LNE
Optional
Pump Feed
b
g/y
o
gr
1
C2
w
Filter
LEN
g/y
S Plan
Valve
Cylinder
Stat
Pump
Timer
230V
50Hz
L NE
L
N
CH on
HW on
LNE
Optional
Pump Feed
Motor
S Plan
Valve
Motor
o
o
gr
b
g/y
b
gr
br
br
Electrical
Filter
LEN
Y Plan, Room Thermostat System, CH Interlocked By Room Thermostat
At least the Radiator(s) near the Room Thermostat not TRV’d
Pump run from Switched Live
By-pass permitted but not required for Part L1 compliance
S Plan, Room Thermostat System, CH Interlocked By Room Thermostat
At least the Radiator(s) near the Room Thermostat not TRV’d
Pump run from Switched Live
By-pass permitted but not required for Part L1 compliance
Y Plan, Fully TRV’d System, CH Interlocked By Boiler Flow Switch
Room Thermostat should not be fitted
Pump must be run from Boiler Optional Pump Feed connection for Part L1 compliance
By-pass not permitted (must be valved off) for Part L1 compliance
S Plan, Fully TRV’d System, CH Interlocked By Boiler Flow Switch
Room Thermostat should not be fitted
Pump must be run from Boiler Optional Pump Feed connection for Part L1 compliance
By-pass not permitted (must be valved off) for Part L1 compliance
Key to colours
b - Blue
br - Brown
w - White
o - Orange
gr - Grey
g/y - Green/Yellow

6.0 System Details
13
6.4 Pipework
1. The sizes of flow and return pipes from the boiler should
be determined by normal methods, according to the
requirements of the system. The connection to the boiler is
22mm compression fitting.
2. Due to space requirements at the rear of the tap bracket,
pipework should comprise of solder fittings.
3. A 20 °C (36°F) drop in temperature across the system is
recommended for condensing boilers. Existing radiators may
be oversized and so allow this, but where radiator sizing is
marginal it may be advisable to retain a system temperature
drop of 11°C (20°F).
. In systems using non-metallic pipework it is necessary to
use copper pipe for the boiler Flow and Return. The copper
must extend at least 1 metre from the boiler and include any
branches (Fig. 9).
6.5 Thermal Stores
1. When the Baxi System 100 HE Plus is itted in
conjunction with a thermal store, both jumpers must be
removed rom the Control PCB, see Fig. 34 Section 8.7.
Boiler Flow
Return
Copper
0.5m
Copper
1m
Copper
0.5m
Fig. 9

6.0 System Details
1
6.6 System Filling and Pressurising (Fig. 10)
1. A filling point connection on the central heating return
pipework must be provided to facilitate initial filling and
pressurising and also any subsequent water loss
replacement/refilling.
2. The filling method adopted must be in accordance
with the Water Supply (Water Fittings) regulations and
the Water Bylaws (Scotland).
3. Your attention is drawn to, for GB: Guidance G2 .2
and recommendation R2 .2 of the Water Regulations
Guide. for IE: the current edition of I.S. 813 “Domestic
Gas Installations”.
. The sealed primary circuits may be filled or
replenished by means of a temporary connection
between the primary circuit and a supply pipe provided
the arrangement in accordance with Diagram R2 .2a of
the Water Regulations Guide.
5. The temporary hose must be completely removed at
both ends after use.
6.7 Expansion Vessel (Fig. 11)
1. The appliance expansion vessel is pre-charged to 1
bar (10 lb/in2). Therefore, the minimum cold fill pressure
is 1 bar. The vessel is suitable for correct operation for
system capacities up to 125 litres (27.5 gal). For greater
system capacities an additional expansion vessel must be
fitted - refer to BS 707 Pt 1.
6.8 Pressure Relie Valve (Fig. 11)
1. The pressure relief valve is set at 3 bar, therefore all
pipework, fittings, etc. should be suitable for pressures in
excess of 3 bar.
2. The pressure relief discharge pipe should be not less
than 15mm dia, run continuously downward, and
discharge outside the building, preferably over a drain. It
should be routed in such a manner that no hazard
occurs to occupants or causes damage to wiring or
electrical components. The end of the pipe should
terminate facing down and towards the wall.
3. The discharge must not be above a window, entrance
or other public access. Consideration must be given to
the possibility that boiling water/steam could discharge
from the pipe.
Fig. 10
Stop
Valve
Double
Check
Valve
Cold
Mains
CH
Return
Temporary
Hose
Stop
Valve
Pressure Relief
Valve
Expansion Vessel
removed for clarity
Fig. 11
Expansion Vessel

7.0 Site Requirements
15
7.1 Location
NOTE: Due to the high e iciency o the boiler a plume
o water vapour will be discharged rom the lue. This
should be taken into account when siting the lue
terminal.
1. The boiler may be fitted to any suitable wall with the flue
passing through an outside wall or roof and discharging to
atmosphere in a position permitting satisfactory removal of
combustion products and providing an adequate air supply.
The boiler should be fitted within the building unless
otherwise protected by a suitable enclosure i.e. garage or
outhouse. (The boiler may be fitted inside a cupboard - see
Section 7.2).
2. If the boiler is sited in an unheated enclosure then it is
recommended to incorporate in the system controls a
suitable device for frost protection.
3. If the boiler is fitted in a room containing a bath or shower,
it can only be fitted in zone 3, (Figs. A & B shows zone
dimensions for a bathtub. For other examples refer to
Section 601 of the Current I.E.E. Wiring Regulations)
reference must be made to the relevant requirements.
In GB this is the current I.E.E. Wiring Regulations and Building
Regulations.
In IE reference should be made to the current edition of I.S.
813 “Domestic Gas Installations” and the current ETCI rules.
. If the boiler is to be fitted into a building of timber frame
construction then reference must be made to the current
edition of Institute of Gas Engineers Publication IGE/UP/7
(Gas Installations in Timber Framed Housing).
7.2 Ventilation o Compartments
1. Where the boiler is installed in a cupboard or
compartment, no air vents are required for cooling purposes
providing that the minimum dimensions below are
maintained.
Sides 25mm
Top 200mm
Bottom 200mm
Front 100mm
2. If the boiler is installed in a smaller cupboard or
compartment it must be ventilated according to
BS 5 0 Part 2 and the minimum clearances given in section
.0 “Technical Data” maintained.
3. Any compartment should be large enough to house the
boiler only.
NOTE: The ventilation label on the ront o the outer case
MUST NOT BE REMOVED when the appliance is installed
in a compartment or cupboard.
Zone 2
Zone 1
Zone 0
Zone 2
Zone 3
Zone 3
Zone 2
Window
Recess
Window
Recess
0.6 m 2. m
Ceiling
Outside
Zones
Outside Zones
Zone 3
Zone 3
Zone 2
Zone 2
Zone 1
Zone 0
2.25 m
Zone 2
Window
Recess
3.0 m
2. m
0.6 m
Fig. A
Fig. B
In GB Only
In GB Only

7.0 Site Requirements
16
7.3 Clearances (Figs. 13 &1 )
1. A flat vertical area is required for the installation of the
boiler.
2. These dimensions include the necessary clearances around
the boiler for case removal, spanner access and air
movement. Additional clearances may be required for the
passage of pipes around local obstructions such as joists
running parallel to the front face of the boiler.
3. For unventilated compartments see Section 7.2.
7.4 Gas Supply
1. The gas installation should be in accordance with the
relevant standards. In GB this is BS 6891. In IE this is the
current edition of I.S. 813 “Domestic Gas Installations”.
2. The connection to the appliance is 1/2” BSPF.
3. Ensure that the pipework from the meter to the appliance
is of adequate size. (22mm recommended at the appliance).
Do not use pipes o a smaller diameter than 22mm up to
the boiler connection.
7.5 Electrical Supply
1. External wiring must be correctly earthed, polarised and in
accordance with relevant regulations/rules. In GB this is the
current I.E.E. Wiring Regulations. In IE reference should be
made to the current edition of ETCI rules.
2. The mains supply is 230V ~ 50Hz fused at 3A.
NOTE: The method o connection to the electricity
supply must acilitate complete electrical isolation o the
appliance. Connection may be via a used double-pole
isolator with a contact separation o at least 3mm in all
poles and servicing the boiler and system controls only.
WARNING: The PCB Control and Fan
Assembly is 3 5 Vdc. Isolate at supply before
access.
200mm
850mm
90mm
200mm
5mm Min
5mm Min
5mm
500mm
For Servicing
Purposes
Fig. 13
Fig. 14 In Operation
3°
(1 in 20)
320mm

7.0 Site Requirements
17
7.6 Condensate Drain
FAILURE TO INSTALL THE CONDENSATE
DISCHARGE PIPEWORK CORRECTLY WILL AFFECT
THE RELIABLE OPERATION OF THE BOILER
The condensate discharge pipe MUST NOT RISE at any
point along its length. There MUST be a all o AT LEAST
2.5° (50mm per metre) along the entire run.
NOTE: It is unnecessary to it an air break in the
discharge pipe.
1. The condensate outlet terminates in a 1” BSP nut and seal
for the connection of 21.5mm (3/in) plastic overflow pipe
which should generally discharge internally into the household
drainage system. If this is not possible, discharge into an outside
drain is acceptable.
2. Ensure the discharge of condensate complies with any
national or local regulations in force.
BS 6798:2000 & Part H1 o the Building Regulations give
urther guidance.
3. The discharge pipe should be run in a proprietary drain pipe
material e.g. PVC, PVC-U, ABS, PVC-C or PP.
. Metal pipework is NOT suitable for use in condensate
discharge systems.
5. The pipe should be a minimum of 21.5mm diameter and
must be supported using suitably spaced clips to prevent
sagging.
6. Any pipe fitted externally must be kept as short as possible
to minimise the potential of freezing.
7. Any condensate discharge pipework external to the building
(or in an unheated part of it e.g. garage) must be insulated to
protect against frost. It is also recommended that the pipe
diameter is increased to 32mm.
8. If the boiler is fitted in an unheated location the entire
condensate discharge pipe should be treated as an external
run.
9. In all cases discharge pipe must be installed to aid disposal of
the condensate. To reduce the risk of condensate being
trapped, as few bends and fittings as possible should be used.
10. When discharging condensate into a soil stack or waste
pipe the effects of existing plumbing must be considered. If soil
pipes or waste pipes are subjected to internal pressure
fluctuations when WC's are flushed or sinks emptied then
back-pressure may force water out of the boiler trap and cause
appliance lockout.
Examples are shown of the following methods of termination:-
i) to an internal soil & vent pipe
ii) via an internal discharge branch (e.g. sink waste)
iii) to a drain or gully
iv) to a purpose made soakaway
Boiler
2.5° Minimum fall
Termination to an internal soil and vent
pipe
50mm min
Boiler
2.5° Minimum fall
External termination via internal discharge
branch
e.g sink waste - downstream
Sink
Pipe must terminate
above water level but
below surrounding
surface
Boiler Pipe must terminate above
water level but below
surrounding surface
2.5° Minimum fall
Termination to a drain or gully
Boiler
500mm min
2.5° Minimum fall
Termination to a purpose made soak-
away
Holes in the soak-away must
face away from the building
50mm per metre of pipe run
50mm per metre of pipe run
50mm per metre of pipe run
50mm per metre of pipe run

7.0 Site Requirements
18
7.7 Flue
NOTE: Due to the high e iciency o the boiler a plume
o water vapour will be discharged rom the lue. This
should be taken into account when siting the lue
terminal.
1. The following guidelines indicate the general
requirements for siting balanced flue terminals.
For GB recommendations are given in BS 5 0 Pt. 1.
For IE recommendations are given in the current edition of
I.S. 813 “Domestic Gas Installations”.
2. If the terminal discharges onto a pathway or passageway,
check that combustion products will not cause a nuisance
and that the terminal will not obstruct the passageway.
3. Take into consideration the effect the plume of vapour
may have on neighbours when siting the flue.
. Adjacent surfaces close to the flue terminal may need
protection from the effects of condensation. Alternatively
a flue deflector kit (part no. 2 8167) is available.
5. For installation of the flue into an internal corner at the
25mm dimension the flue deflector kit (part no. 2 8167)
must be fitted.
6. * Reduction to the boundary is possible down to 25mm
but the flue deflector kit (part no. 2 8167) must be fitted.
7. If required a suitable terminal guard is available from
Baxi for use with the flue deflector.
8. For fitting under low soffits and eaves it is acceptable for
the flue to project up to 500mm from the face of the wall
to the inside of the air intake. This can be painted if
required using a suitable external paint.
9. If a terminal is less than 2 metres (783/in) above a
balcony, above ground or above a flat roof to which
people have access, then a suitable terminal guard must be
provided.
Fig. 16
Fig. 15
300 min
Terminal
Assembly
Top View Rear Flue
Property Boundary Line
NOTE: The distance from a fanned draught appliance terminal
installed parallel to a boundary may not be less than 300mm in
accordance with the diagram below
Table. 2
Terminal Position with Minimum Distance (Fig. 16) (mm)
AaDirectly below an opening, air brick, opening
windows, etc. 300
BaAbove an opening, air brick, opening window etc. 300
CaHorizontally to an opening, air brick, opening window etc. 300
D Below gutters, soil pipes or drain pipes. 25
E Below eaves. 25
F Below balconies or car port roof. 25
G From a vertical drain pipe or soil pipe. 25
H From an internal (i) or external (ii) corner. (i) 25 (ii) 115
I Above ground, roof or balcony level. 300
J From a surface or boundary line facing a terminal. 600
K From a terminal facing a terminal (Horizontal flue). 1200
From a terminal facing a terminal (Vertical flue). 600
L From an opening in carport (e.g. door, window)
into the dwelling. 1200
M Vertically from a terminal on the same wall. 1500
N Horizontally from a terminal on the same wall. 300
R From adjacent wall to flue (vertical only). 300
S From an adjacent opening window (vertical only). 1000
aIn addition, the terminal should be no nearer than 150 mm to an
opening in the building fabric formed for the purpose of accommodating
a built-in element such as a window frame. See BS 5 0 Pt. 1.
*

7.0 Site Requirements
19
7.8 Flue Dimensions
See Section 2.2. The standard horizontal flue kit allows for
flue lengths between 270mm (105/8”) and 800mm (32”)
from elbow to terminal (Fig. 17).
The maximum permissible equivalent lue length is: 4
metres (Fig. 18).
NOTE: Each additional 45° o lue bend will account
or an equivalent lue length o 0.5m.
eg. 45° = 0.5m, 90° = 2 x 45° = 1m etc.
7.9 Terminal Guard (Fig. 19)
1. When codes of practice dictate the use of terminal
guards, they can be obtained from most Plumbers’ and
Builders’ Merchants.
2. There must be a clearance of at least 50mm between any
part of the terminal and the guard.
3. When ordering a terminal guard, quote the appliance
model number.
. The flue terminal guard should be positioned centrally
over the terminal and fixed as illustrated.
7.10 Vertical Flue
1. Only a flue approved with the Baxi System 100 HE Plus
can be used.
2. For information on vertical flues consult the Baxi Flue
Guide Brochure or Notes for Guidance supplied with the
vertical flue pack.
Fig. 17
Fig. 18
Pictorial examples o lue runs where EQUIVALENT lue length equals 4m
Fig. 19
270mm 800mm
0.5m
1m
0.5m
0.5m

7.0 Site Requirements
20
7.11 Flue options
Concentric
The maximum equivalent lengths are m (horizontal) or
(vertical). There lengths exclude the standard elbow and
flue/terminal assembly (horizontal) and terminal assembly
(vertical).
Twin Flue
The total maximum equivalent flue length is 150m.
NOTE: Each 1m of flue duct should be calculated as 2m.
Any additional “in line” bends in the flue system must be
taken into consideration. Their equivalent lengths are:
Concentric Pipes: 5° bend 0.5 m
93° bend 1.0 m
Twin Flue Pipe: 5° bend (air duct) 1.3 m
5° bend (flue duct) 2.6 m
90° bend (air duct) .8 m
90° bend (flue duct) 9.6 m
Detailed examples of equivalent flue length calculation are
given in the Installation Guidance Notes for each flue system
type.
(Documents 2 3501 and 2 3502 for concentric and twin
pipe respectively).
A - Standard Flue
D
C
B
E
K
L
M
D
J
F
J
N
HG
R
Key Accessory Size Baxi Code
Number
Concentric Flue System 110mm diameter
A Horizontal flue kit 850mm 236921
B Straight extension kit 1000mm 2 1695
500mm 2 169
250mm 2 1692
C Bend kit 93° 2 1687
D Bend kit (pair) 5° 2 1689
E Horizontal flue terminal 2 3013BAX
Clamp 110mm 2 301 BAX
Twin Flue System 80mm diameter
F Straight extension kit 1000mm 238690
500mm 238692
250mm 23869
G Bend kit 90° 2 6139
H Bend kit (pair) 5° 2 6138
Universal Vertical Flue Kits
J Twin flue adaptor kit 2 2757
K Vertical flue terminal 2 2802
L Universal roof tile 25°/50° 2 3015
M Roof cover plate kit 2 3131
N Flat roof flashing 2 3016BAX
R Vertical flue adaptor 5106888
Clamp 80mm 23868