Baxi Genesis 80 User guide

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Please leave these Instructions with the User
Baxi Genesis
Gas Fired Wall Mounted Combination Boiler
Natural Gas, Propane & Butane
Comp No. 236463 - 10/96
Baxi Genesis 80 – G.C.No47 077 01
Baxi Genesis 96 – G.C.No47 077 02
Installation
and
Servicing
Instructions

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Baxi Heating Ltd is one of the leading manufacturers of
domestic heating products in the U.K.
Our first priority is to give a high quality service to our
customers. Quality is built into every Baxi product -products
which fulfil the demands and needs of consumers, 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.
Baxi is also the largest manufacturing partnership in the
country. Everyone who works at the company has a
commitment to quality because, as shareholders, we know
that satisfied customers mean continued success.
We hope you get a satisfactory service from Baxi. If not,
please let us know
Baxi is a BS-EN ISO 9002 Accredited Company

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Contents – Page 3
Introduction PAGE 4
General Layout PAGE 5
Appliance Operation PAGE 6
Technical Data PAGE 7-8
General Dimensions & Fixings PAGE 9
System Details PAGE 10-12
Central Heating circuit
Bypass
System Control
System Filling & Pressurising
Pressure Vessel
Pressure Relief Valve
Domestic Hot Water Circuit
Showers
Hard Water Areas
Site Requirements PAGE 13-16
B.S. Codes of Practice
Clearances
Location
Ventilation of Compartments
Gas Supply
Electrical Supply
Flue
Terminal Guard
Installation PAGE 17-24
Initial Preparation
Flushing
Preparing the Boiler
Fitting the Boiler
Fitting the Flue
Making the Electrical Connections
Commissioning the Appliance PAGE 26
Servicing The Appliance PAGE 27
Changing Components PAGE 28-41
Pressure Switch
Fan
Gas Valve Solenoids
Domestic Hot Water Heat Exchanger
Heat Exchanger
Pump
PCB & Spark Generator
Thermistors
Safety Thermostat
Expansion Vessel
Pressure Relief Valve
Pressure Gauge
Flow Switches
Flame Sensing Probe
Spark Electrode
Injector Manifold
3-Way Valve
Water Filters
Automatic Air Vent
Flow Regulator
Fault Finding PAGE 42-50
Short Parts List PAGE 51

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Introduction – Page 4
Description
The Baxi Genesis 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.
Genesis 80
The boiler is preset to give a maximum output of 23.25 kW
(79,347 Btu/hr) for both hot water and central heating
modes.
Genesis 96
The boiler is preset to give a maximum output of 28.0 kW
(95,555 Btu/hr) for both hot water and central heating
modes.
It is designed for use on natural gas (G20). Using the
conversion kit it can be used on LPG (Propane G31 or
Butane G30).
The boiler is suitable for use only on fully pumped sealed
heating systems. Priority is given to domestic hot water.
The appliance data badge is positioned on the electrical box
behind the outer case.
A label on the user door panel gives details of the model,
serial number and Gas Council number.
Optional Extras
KIT PART No
Flue extension 1 M (Use two kits for 2M etc.) 236439
Flue Extension 0.25M 238605
Flue Extension 0.5M 238604
DHW Expansion Vessel Kit 238395
Wall liner/internal fixing 236441
Programmable room thermostat 24 hr. 236254
Programmable room thermostat 7 day 238326
Integral 7 day Electronic Timer Kit 238399
Integral 12 hr. AM/PM 8ectro-Mechanical
Timer Kit 238398
80 LPG Conversion - Propane & Butane 235983
96 LPG Conversion - Propane & Butane 237474
Flue bend - 45º 236467
Flue bend - 90º 236466
Vertical Flue Equipment -
See Installer’s Guide or Notes For Guidance

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General Layout – Page 5
1Chassis with Expansion Vessel
2Combustion Box
3Fan Assembly
4Primary Heat Exchanger
5Combustion Chamber
6Burner Assembly and Electrodes
7Gas Valve Assembly
8Automatic Air Seperator and Vent
9Flow Switch Heating Circuit
10 Flow Switch DHW Circuit
11 Circulation Pump
12 Electrical Box
13 Safety Thermostat
14 By-Pass Valve
15 DHW Thermostat Sensor
16 CH Thermostat Sensor
17 Three Way Valve
18 DHW Plate Heat Exchanger
19 Selector Switch On-Off
20 DHW Temperature Adjustment
21 Heating Temperature Adjustment
22 Heating Temperature Indicator
23 Green Light - Power On
24 Orange Light - Boiler On
25 Red Light - Flame Failure
26 Flame Failure Reset Button
27 Pressure Gauge
28 Pressure Switch
29 Isolating Valves
30 Optional Integral Timers

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Appliance Operation – Page 6
CENTRAL HEATING MODE
With a demand for heating the pump (11) circulates water
through the primary circuit. At a flow rate of approximately
250 I/hr the central heating flow switch (9) operates,
commencing the ignition sequence.
The main burner (6) ignites at 1/3 rate then switches to full
gas rate. The gas valve (7) controls the gas rate “HIGH -
LOW” to maintain the heating temperature measured by the
thermostat sensor (16).
When demand is satisfied the burner is extinguished, the
pump continues to run. The duration of each OFF cycle is 3
minutes before re-lighting automatically. Each ON cycle
commences with a 45 second duration at third gas rate
before switching to full rate if necessary.
On completion of a heating period the pump will continue to
run for a period of 3 minutes (PUMP OVERRUN).
DOMESTIC HOT WATER MODE
Priority is given to hot water supply. A demand at a tap or
shower will override any central heating requirement.
The flow of cold water will operate the DHW flow switch (10)
which requests the 3 way valve (17) to change position to
allow the pump (11) to circulate the primary water through
the secondary DHW heat exchanger (18).
The appliance-will light automatically and the temperature of
the domestic water is controlled by the thermostat sensor
(15).
When the hot water demand ceases the burner will
extinguish and for a period of 3 minutes the appliance
remains ready in the DHW mode before returning to the
central heating mode.

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Technical Data – Page 7
GENESIS 80

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Technical Data – Page 8
GENESIS 96

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General Dimensions and Fixings – Page 9

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System Details – Page 10
The Genesis Combination Boiler is a ‘Water Byelaws
Scheme - Approved Product’.
To comply with the Water Byelaws your attention is
drawn to the following installation requirements and
notes (IRN).
1) IRN 001 - See text of entry for installation requirements
and notes.
2) IRN 116- Byelaw 90 and 91.
3) IAN 302 - Byelaw 14.
Reference to the WRc publications, ‘Water fittings and
materials directory’ and ‘Water supply byelaws guide’ give
full details of byelaws and the IRNs.
Central Heating Circuit
The appliance is suitable for fully pumped SEALED
SYSTEMS ONLY.
All systems should be thoroughly flushed prior to
connection of the appliance. If the installation is on an
existing sealed system, or a modified open system, it is
particularly important to flush preferably using an
appropriate descaling/flushing agent.
Where used, corrosion inhibitors, flushing agents/descalers
should be approved and suitable for all system metals.
BYPASS
The appliance has an integral pre-set bypass, therefore no
external bypass on the system is required. TRV’s can be -
used on all radiators.
SYSTEM CONTROL
Operation of the system under control of the boiler
thermostat only does not produce the best results. The
heating system should include a control system. This should
comprise of at least a single channel timer.
Integral Single Channel Timer Kits are available as optional
extras.
For optimum operating conditions and best economy the
fitting of a programmable thermostat is recommended.
Programmable thermostats - the ‘Baxi Genesis
Controllers’ are available as an optional extra.

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SYSTEM DETAILS – Page 11
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.
The filling method adopted must be in accordance with
all relevant water supply byelaws using approved
equipment.
Your attention is drawn to: IRN 302 and Byelaw 14.
Unvented primary circuits may be filled or replenished by
means of a temporary connection between the circuit and a
supply pipe provided a ‘Listed’ double check valve or some
other no less effective backflow prevention device is
permanently connected at the inlet to the circuit and the
temporary connection is removed after use.
PRESSURE VESSEL
The appliance expansion vessel is pre-charged to 0.7 bar
(10 lb/in2). Therefore, the minimum cold fill pressure is 0.7
bar. The vessel is suitable for correct operation for system
capacities up to 125 litres (27.5gal). For greater system
capacities an additional expansion vessel must be fitted -
refer to BS 7074 Pt 1.
PRESSURE RELIEF VALVE
The pressure relief valve is set at 3 bar, therefore all
pipework, fittings etc should be suitable for pressures in
excess of 3 bar.
The pressure relief discharge pipe should be not less than
15mm, run continuously downward, and discharge outside
the building, preferably over a drain, and in such a manner
that no hazard occurs to occupants or cause damage to
wiring or electrical components.
The end of the pipe should terminate facing down and
towards the wall.
THE DISCHARGE MUST NOT BE ABOVE A WINDOW,
ENTRANCE OR OTHER PUBLIC ACCESS.
CONSIDERATION MUST BE GIVEN TO THE POSSIBIUTY
THAT BOILING WATER /STEAM COULD DISCHARGE
FROM THE PIPE.

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SYSTEM DETAILS – Page 12
Domestic Hot Water Circuit
All DHW circuits, connections, fittings etc should be
fully in accordance with relevant standards and water
supply bye-laws.
Your attention is drawn to: IRN 116 and Byelaw 90 and 91.
Sealed primary circuits and / or secondary hot water
systems shall incorporate a means for accommodating the
thermal expansion of water to prevent any discharge from
the circuit and / or system except in an emergency situation.
When the system includes any device which prevents water
expanding back towards the supply (check valve, loose
jumpered stopcock; water meter, water treatment device),
then an expansion vessel must be fitted e.g. (Zilmet 160ml,
R ½ 15bar).
To comply with Byelaw 91,a check valve must also be fitted
on the supply as shown, to ensure efficient operation and
also to prevent the reverse flow of hot water into the supply
pipe.
IF THE HOT WATER EXPANSION IS NOT PROVIDED
FOR, THEN HIGH PRESSURES CAN DEVELOP WHICH
MAY RESULT IN DAMAGE TO FITTINGS AND DEVICES
ON THE SYSTEM.
The appliance maximum working mains pressure is 10 bar
(150 lb/in2), therefore all pipework, connections, fittings etc
should be suitable for pressures in excess of 10 bar: A
pressure reducing valve must be fitted for pressures in any
outlet fittings, such as a shower excess of 10 bar: The
manufacturer of valve, may require a lower maximum
pressure. The pressure reduction must take account of all
fittings connected to the DHW system.
SHOWERS
If a shower control is supplied from the appliance it should
be of the thermostatic or pressure balanced type.
Thermostatic type shower valves provide the best comfort
and guard against water at too high a temperature. Existing
controls may not be suitable - refer to the shower
manufacturers.
HARD WATER AREAS
If the area of the installation is recognised as a HARD
WATER AREA then a suitable device should be fitted to
treat the mains water supply to the appliance.

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Site Requirements – Page 13
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 instruction is given reference should be
made to the relevant British Standard Codes of Practice.)
B.S. Codes of Practice
Standard Scope
BS 6891 Gas Installation.
BS 5546 Installation of hot water supplies for
domestic purposes.
BS 5449 Part 1 Forced circulation hot water systems.
BS 6798 Installation of gas fired hot water
boilers.
BS 5440 Part 1 Flues.
BS 5440 Part 2 Air supply
BS 7074 Expansion vessels and ancillary
equipment for sealed water systems.
WARNING
The addition of anything that may interfere with the
normal operation of the appliance without the express
written permission of Baxi Heating could invalidate the
appliance warranty and infringe the GAS SAFETY
(Installation and Use) REGULATIONS.
Clearances
A flat vertical area is required for the installation of the boiler.
These dimensions include the necessary clearances around
the appliance 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 appliance.
Location
The appliance may be fitted to any suitable wall with the flue
passing through an outside wall and discharging to
atmosphere in a position permitting satisfactory removal of
combustion products and providing an adequate air supply.
The appliance should be fitted within the building unless
otherwise protected by a suitable enclosure ie. garage or
outhouse. (The appliance may be fitted inside a cupboard -
see page 14).
If the appliance is fitted in a room containing a bath or
shower reference must be made to the Current I.E.E. Wiring
Regulations and Building Regulations. If the appliance is to
be fitted into a building of timber frame construction then
reference must be made to British Gas document DM2.

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SITE REQUIREMENTS – Page 14
Ventilation of Compartments
Where the appliance is installed in a cupboard or
compartment, air vents are required (for cooling purposes) in
the cupboard or compartment at high and low level which
may communicate with a room or direct to outside air.
Detailed recommendations for air supply are given
in BS 5440: Part 2.
An existing cupboard or compartment may be used,
provided that it is modified for the purpose.
Recommendations for air supplies and details of -essential
cupboard compartment design are given In BS 5440:Part2.
NOTE:-Both air vents must communicate with the same
room or both be on the same wall to outside air.
Genesis 80
Position of Air from Air direct
Air Vent Room from Outside
High 257cm2(39in2)128cm2(19.5in2)
Low 257cm2(39in2)128cm2(19.5in2)
Genesis 96
Position of Air from Air direct
Air Vent Room from Outside
High 311cm2(48.2 in2)156cm2(24.1 in2)
Low 311cm2(48.2 in2)156cm2(24.1 in2)
Gas Supply
The-gas installation should be in accordance with BS 6891.
The connection to the appliance is a 22mm copper tail
located at the rear of the gas cock.
Ensure that the pipework from the meter to the appliance is
of adequate size. Do not use pipes of a smaller diameter
than the appliance gas connection.
Electrical Supply
External wiring must be correctly earthed, polarized and in
accordance with current I.E.E. Wiring Regulations.
The mains supply is 230V - 50Hz fused at 3A.
NOTE:-The method of connection to the electricity
supply must facilitate complete electrical isolation of the
appliance.
Connection may be via a fused double-pole isolator with a
contact separation of at least 3mm in all poles and servicing
the appliance and system controls only.

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SITE REQUIREMENTS – Page 15
Flue
An internal fitting kit is available for installations where the
flue terminal is inaccessible from the outside. -(Part No
236441). This is available from merchants or direct from Baxi
free of charge.
The following guidelines indicate the general requirements
for siting balanced flue terminals. Recommendations for
flues are given in BS 5440 Pt.1.
If the terminal is fitted within 1 metre (39 in) of a plastic
gutter, within 500mm (19 ½ in) of a painted eave or a
painted gutter, an aluminium shield of at least 1 metre (39 in)
long should be fitted to the underside of the gutter or painted
surface. An air space of 5mm (3/16 in) should be left
between shield and gutter.
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.
Terminal Position with Minimum Distance (mm)
ADirectly below an openable window or other
opening. e.g. an air brick. 300
BBelow gutters. 25
CBelow eaves, soil pipes or drain pipes. 75
DBelow balconies or car port roof 200
EFrom vertical drain pipes and soil pipes. 75
FFrom internal or external corners. 25
GAbove ground, roof or balcony level. 300
HFrom a surface facing a terminal. 600
IFrom a terminal facing a terminal. 1200
JVertically from a terminal on the same wall. 1500
KHorizontally from a terminal on the same wall. 300
LFor an opening in a car port (e.g. door, window)
into a dwelling. 1200

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SITE REQUIREMENTS – Page 16
Flue Dimensions
The standard flue supplied with the appliance is suitable for
use with flue lengths between 220mm (8 21/32in) and
610mm (24in).
TOTAL FLUE LENGTH PERMISSIBLE IS:
3 METRES MAX.
Terminal Guard
When codes of practice dictate the use of terminal guards,
they can be obtained from most Plumbers and Builders
Merchants nationwide.
When ordering a terminal guard, quote the appliance model
number.
The guard manufacturers listed below can be contacted for
terminal sizes and guard model numbers.
Tower Flue Components Ltd.,
Tower House,
Vale Rise,
Tonbridge,
Kent.
Tel: [phone].
Quinnell, Barrett & Quinnell,
884 Old Kent Road,
London, SE15 1NL
Tel: [phone].
FIXING
The flue terminal guard should be positioned centrally over
the terminal and fixed as illustrated.

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Installation – Page 17
Initial Preparation
Remove the fixing template from the small carton.
After considering the site requirements (see page 13)
position the template on the wall.
Mark the position of the fixing holes for the two hooks. Use
the upper two holes where possible.
Mark the centre of the flue hole (rear exit). For side exit,
mark as shown. If required, mark the position of the gas and
water pipes. Remove the template.
Cut the hole for the flue (minimum diameter 107mm).
Drill and plug the wall as previously marked. Secure the two
hooks to the wall.
Insert the two outer support bracket fixing screws, leaving
them sufficiently proud to engage in the keyhole slots.
GENESIS 96 ONLY
Before fixing the support bracket to the wall remove the blue
regulator unit from the inlet connection of the cold water
isolating valve. Replace with the red regulator supplied in
the contents kit (See page 41).
Attach the support bracket and ensuring it is level, secure to
the wall.
Insert the two inner screws.
Connect the gas and water pipes to the valves on the
support bracket using the copper tails supplied. Ensure the
sealing washers are fitted correctly. (The rubber washer is
for use on the gas connection only. The fibre washers
are for the water circuit connections.)
Connect a pressure relief discharge pipe to the safety valve
tail routed to discharge safely outside the property.
The symbols for each connection are embossed on the
support bracket.
Flushing
Flush thoroughly (see system notes). There is a plastic tube
in the contents kit to aid flushing.
Insert in to valve outlet as shown.
Fit the water filter supplied in the kit to the cold water inlet
valve.

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INSTALLATION – Page 18
Preparing The Boiler
Follow the sequence depicted on the carton to unpack the
boiler.
Remove the lower cover poly bag assembly and contents kit
before laying the boiler on its back supported by the
polystyrene block.
Hinge down the lower door panel and spring off.
Remove the four securing screws, slide and lift away the
outer case.
Remove the sealing plugs from the copper bends.
Stand the boiler on its base on the carton sleeve.
Note: A small amount of water may drain from the boiler
in the upright position.

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INSTALLATION – Page 19
Fitting The Boiler
Lift the boiler using the lower edge of the combustion box
and the hand holds in the chassis.
Place boiler on the support bracket, slide back then lift to
engage on top hooks.
Hinge down the electrical box to gain access to the
connections between boiler and valves.
At both sides push in the two tabs - hinge box down by
rotating.
Check the inlet water filter is fitted (F).
Make the gas connection first (G). This will centralise the
boiler.
Insert the sealing washers between the valve outlet face and
the flange on the copper bends. The rubber washer is for
use on the gas connection only. The fibre washers are
for the water circuit connections.
Tighten the connections.

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Fitting The Flue – Page 20
HORIZONTAL FLUE
The standard flue supplied with the appliance is suitable for
lengths 220mm minimum to 610mm maximum.
Rear flue: maximum wall thickness - 490mm.
Side flue,
(left or right): maximum wall thickness - 477mm.
If fitting the optional Intel fitting kit, flue extension kit or
elbows refer to the instructions provided with the kits.
Place the flue elbow on to the flue connection, with the
outlets facing the wall opening.
Measure the distance from the outside wall face to the
elbow. This is to be dimension (X)
Mark dimension (X) on the plastic air duct measuring from
the flue terminal as shown.
Measure the length of waste material from the air duct.
Take the aluminium flue duct and mark off this length. from
the plain end. Do not cut the flared end.
The required dimension of the flue duct is (X)+55mm.
IMPORTANT:
Check your measurements before cutting.
Cut the ducts to size.