Baxi Maxflow Combi WM Operation instructions

Baxi Maxflow Combi WM
Gas Fired Wall Mounted Combination Boiler
with Unvented Hot Water Storage
User’s Operating
Instructions
Please keep these instructions safe.
Should you move house, please hand
them over to the next occupier.

2
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.
Baxi Maxflow Combi WM
G.C.No47 075 03
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.

1.0 Warnings
3
1.1 Safe 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 registered competent person and be in
accordance with the relevant requirements of
current GAS SAFETY (Installation and Use)
REGULATIONS most recent edition, the BUILDING
REGULATIONS issued by the Department of the
Environment, BUILDING STANDARDS (Scotland)
(Consolidation) REGULATIONS issued by the
Scottish Development Department and the LOCAL
BUILDING REGULATIONS.Where no specific
instructions are given, reference should be made
to the relevant BRITISH STANDARD CODES OF
PRACTICE and INSTALLATION
SPECIFICATIONS.
2. This appliance must be installed in
accordance with the manufacturer’s instructions
and the rules in force, and only used in a suitably
ventilated location.
3. Read the instructions before installing or
using this appliance.
4. Any purpose provided ventilation should be
checked periodically to ensure that it is free from
obstruction.
IMPORTANT - The addition of anything that
may interfere with the normal operation of the
appliance without the express written
permission of Baxi UK Limited could invalidate
the appliance warranty and infringe the GAS
SAFETY (Installation and Use) REGULATIONS.
1.2 In case of gas leaks
1. If a gas leak is found or suspected, turn off the
gas supply at the meter immediately and at the
isolating valve on the boiler if possible. Contact your
Installer or Transco (under ‘Gas’in the ‘phone
directory).
1.3 Servicing your Appliance
1. For reasons of safety and economy your
appliance should be serviced annually. Servicing
must be performed by a competent person. Your
Installer or British Gas Service will be able to advise
you.
1.4 Electricity Supply
1. THIS APPLIANCE MUST BE EARTHED.
2. A standard 230V ~ 50Hzsupply is required. The
appliance must be protected by a 3 amp fuse.
STANDARD
B.S. 6891
B.S. 5440: Pt 1
B.S. 5440: Pt 2
B.S. 5546
B.S. 7074
B.S. 5449: Pt 1
B.S. 6798
SCOPE
Gas Installation.
Flues.
Air Supply.
Installation of hot water supplies
for domestic purposes.
Expansion vessels and ancillary
equipment for sealed water systems.
Forced circulation hot water systems.
Installation of gas fired hot water
boilers.
IN AN EMERGENCY
If a water or gas leak occurs or is suspected, the boiler can be
isolated at the inlet valves as follows;
1. Turn off the electrical supply and turn the selector switch on
the facia to the OFF position (see 2.2).
2. The isolating valves are positioned under the boiler and can be
closed using either a flat bladed screwdriver or an open ended
spanner across the flats.
3. Turn the gas tap clockwise to the stop position to isolate the
gas supply at the boiler.
4. To isolate the water system, close the three valves fully by
turning clockwise.
5. Call your Service Engineer as soon as possible.
“Benchmark”Installation, Commissioning and Service Record
Log Book
Please ensure that your installer has completed the Installation and
Commissioning sections of the Log Book and hands the Log Book over.
The details of the Log Book will be required in the event of any warranty
work. Keep the Log Book in a safe place and ensure that the relevant
sections are completed at each subsequent regular service visit.
All CORGI registered installers carry a CORGI identification card and have
a registration number. Both should be recorded in your boiler Log Book.
You can check your installer is registered by telephoning 01256 372300 or
writing to:-
1 Elmwood,
Chineham Business Park,
Crockford Lane,
Basingstoke
RG24 8WG
Never Hang Flammable Items Over The
Appliance
NOTE: Adjacent to the boiler at either the left
or right hand side there will be fitted an
expansion vessel, relief valve. tundish etc.
These components must not be adjusted or
interfered with in any way. They are part of the
Unvented Hot Water Kit and are important
safety items.

2.0 Operating the Boiler
4
2.1 Introduction
1. Your Baxi Maxflow Combi WM is a gas fired,
room sealed, powered flue combination boiler,
which provides central heating for your home and
incorporates a 54 litre unvented hot water storage
cylinder. It is fully automatic and does not have a
pilot light. Frost and pump protection is an integral
part of the appliance. The appliance will provide
between 10.4 and 28.0 kW output.
2. Priority is given to the hot water mode - when a
hot water tap is turned on the supply of heat to the
radiators is interrupted. No reduction in room
temperature should be apparent.
3. A shortened version of these operating
instructions appears on the reverse of the lower
door panel. A label gives details of the model,
serial number, G.C.Noand the manufacturer’s
name and address.
2.2 Operating the Boiler
1. Ensure that the gas and electricity supplies are
turned on and that all timers, thermostats etc. are
calling for heat.
2. Hinge down the facia panel (Fig. 1).
Check that the central heating pressure is in the
green area on the gauge. The Power ON indicator
will be lit ( ).
3. Turn the on-off selector switch either
anti-clockwise from the off position (Fig. 3) to both
central heating and domestic hot water or
clockwise for domestic hot water only.
4. Position (i) In this position the boiler will heat
the radiators according to demand or will heat the
hot water storage cylinder as required (Fig. 4).
5. Position (ii) In this position the boiler will heat
the hot water storage cylinder as required.
(Fig. 5).
7. The boiler will light automatically on demand.
8. The Burner ON indicator ( ) will light when the
boiler is operating and the main burner has lit
(Fig. 2).
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 the
Position (i) or Position (ii).
RESET
Domestic Hot Water
Temperature Control
Central Heating
Temperature Control
Position (ii)
(Hot Water Only)
Position (i)
(Central Heating
or Hot Water)
Fig. 4
Fig. 5
OFF Position Fig. 3
Fig. 2
ON/OFF
Selector Switch
Fig. 1
Facia Panel
Pressure GaugeReset Button
Flame Failure
Reset Button
Indicator
Neons

2.0 Operating the Boiler
5
Domestic Hot Water
Temperature Control
Fig. 6
Central Heating
Temperature Control
Fig. 7
2.3 Temperature Control
1. Central Heating: The central heating hot water
flow temperature can be adjusted between 30°C
minimum and 82°C maximum.
2. Turn the control knob clockwise to increase the
temperature (Fig. 6).
3. In normal winter usage we recommend that the
central heating temperature be set at maximum.
4. Domestic Hot Water: The temperature of the
domestic hot water can be adjusted up to a
maximum of 65°C. Turn the control knob
clockwise to increase the temperature (Fig. 7).
5. It may take a short while, and a degree of
experimentation, to obtain the best performance
from your Baxi Maxflow Combi as the appliance
does not provide domestic hot water in the same
manner as other combi or conventional boilers.
6. When the temperature control is set to
maximum the domestic hot water as delivered will
be too hot for bathing purposes without the
addition of cold water. As a general
recommendation, when the control knob is set
between 90°and 180°clockwise from the OFF
position the hot water will be delivered at a
temperature suitable for most domestic
requirements. This can be adjusted according to
experience and personal requirements.
7. If the store has reached maximum selected
temperature and a hot tap is turned on full to give
a flow rate of approximately 16 litres/min., such as
when filling a bath, it will take approximately 3
minutes to deplete the store. During this time the
boiler will relight ( indicator neon will be
illuminated). Unless the flow rate is reduced
before the store is depleted the water temperature
will not recover. By reducing the flow rate to
around half (or less) approximately two minutes
after first turning the tap on the temperature will be
maintained.
8. If the tap is initially opened approximately half
way to deliver a flow of 8 to 10 litres/min. the boiler
will continue to provide hot water at the selected
temperature.
9. As an example, with the temperature control set
at maximum and the stored water fully heated a
flow rate of 8 litres/min. will provide enough hot
water for the average bath within 5 or 6 minutes.
This would then require the addition of cold water
for bathing comfort.
10. Other factors that will influence the
performance are the temperature of the cold water
supply to the boiler, the ambient air temperature
both outside and in the room in which the hot
water is being drawn off, the distance from the
boiler to the point of draw off, pipe insulation etc.
11. When demand ceases, the boiler will quickly
and automatically replenish the store of hot water
to the selected temperature.

2.0 Operating the Boiler
6
2.4 Indicator Neons
1. The appliance is fitted with six vertically aligned
status indicator neons, and one illuminated reset
button. The indicators are:-
Air Flow Monitor
Safety Thermostat
Burner On
Power To Boiler
Boiler Supplying DHW
Boiler Supplying CH
The illuminated reset button is below the
symbol.
2.5 Air Flow Monitor Indicator
1. The boiler is fitted with an air pressure sensing
device. This monitors the flue system.
2. On starting the boiler the indicator ( ) will be
on while the sensor checks that the fan is
functioning correctly (Fig. 8).
3. If the neon stays on permanently it indicates
that the flue or flue terminal is blocked or
obstructed in some way, or that there is an
internal fault. If there is no external blockage of
the flue terminal that can be easily removed
contact your Service Engineer.
2.6 Safety Thermostat Indicator
1. Your Baxi Maxflow Combi WM is fitted with an
additional safety device, which shuts down the
boiler in the event of the system or the boiler
overheating.
2. If the device operates, the safety thermostat
indicator will light ( ) and the boiler will shut
down.
3. To reset: Press the white reset button (below
the indicator lights) to relight the boiler (Fig. 8).
4. If the safety thermostat operates repeatedly,
causing boiler shutdown, a fault is indicated. Your
Service Engineer should be contacted as soon as
possible.
2.7 Burner On Indicator
1. The indicator ( ) will illuminate once the
burner has ignited. When the burner goes out the
indicator will be extinguished.
2.8 Supply Indicators
1. The supply indicators show whether the boiler
is satisfying the Domestic Hot Water demand ( )
or the Central Heating ( ).
2.9 Flame Failure Reset Button
1. The reset button below the ( ) symbol will
illuminate in the event of the burner failing to light,
or when incomplete lighting of the burner occurs.
2. Pressing the button will restart the ignition
sequence. If the reset button illuminates
repeatedly a fault is indicated. Your Service
Engineer should be contacted as soon as
possible.
RESET
Fig. 8
Reset Button
Air Flow Monitor
Safety Thermostat
Burner On
Power On
Domestic Hot Water Mode
Central Heating Mode
Flame Failure
Reset Button

2.0 Operating the Boiler
7
2.10 Central Heating System Pressure
1. The water pressure in the central heating
system is indicated by the pressure gauge.
2. The recommended system pressure when cold
is 1.0 bar (Fig. 9). The minimum pressure is
0.5 bar (Fig. 11), the maximum is 2.5 bar (Fig. 12).
3. A pressure of 2.5 or greater indicates a fault.
The safety pressure relief valve will operate at a
pressure of 3. It is important that your Service
Engineer is contacted as soon as possible in the
event of over pressurisation of the system.
4. The MINIMUM pressure for correct operation is
0.5 (Fig. 11). If the pressure falls below 0.5, this
may indicate a leak on the central heating system.
Below 0.5 the boiler will not function.
5. The system must be checked and
re-pressurised by your Service Engineer.
2.11 To Shut Off the Boiler
1. For short periods: Turn the selector switch to
the DHW position ( , Fig. 14).
2. For longer periods: Turn the selector switch to
the OFF position (Fig. 15) and turn off the
electricity and gas supplies.
If your home is to be left unoccupied for long
periods during cold weather the boiler and
whole system should be drained unless there is
additional frost protection.
3. Your installer will advise you about frost
protection and draining the system.
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 the Position (i) or Position (ii).
2.12 Frost Protection Mode
1. The frost protection feature will operate when
the selector switch is in the central heating and
domestic hot water mode.
The gas and electrical supplies to the boiler must
be on and the system pressure must be within the
range described in Section 2.10.
2. If the system temperature falls below 5°C, then
the boiler will fire until the water temperature has
been raised.
3. Further frost protection can be incorporated by
using a frost thermostat to protect the whole
system.
2.13 Pump Protection
1. With the selector switch in either operating
position (Figs. 13 & 14) the pump will
automatically operate for 1 minute in every 24
hours to prevent sticking.
0
1
2
3
4
CORRECT PRESSURE WHEN COLD
bar
0
1
2
3
4
CORRECT PRESSURE WHEN COLD
bar
0
1
2
3
4
CORRECT PRESSURE WHEN COLD
bar
Fig. 11
Fig. 9
Fig. 12
Fig. 14
Fig. 13
Fig. 15
Correct pressure when cold
Minimum operating pressure Maximum operating pressure
OFF Position
Domestic
Hot Water
Fig. 10
Fig. 16
Central Heating and
Domestic Hot Water

3.0 Clearances
8
3.1 Clearances around the Boiler
(Figs. 17 & 18)
1. The minimum clear spaces needed around
the boiler measured from the casing are as
follows:
Top - 200mm
Bottom - 250mm
Left hand side - 20mm
Right hand side - 5mm
Front - 450mm (For Servicing)
5mm (In operation)
2. These areas must not be obstructed in any
way. Blocking the clearance spaces may
result in the boiler overheating and damage
may occur.
3. The gas burning compartment of your boiler is
completely sealed from the room in which it is
fitted. Products from the combustion of gas are
vented to the outside through the flue terminal
which must be kept free from obstruction as this
would interfere with the correct operation of the
boiler.
4. The boiler may be installed in a cupboard or
compartment if the following clearances are
kept:-
Top - No clearances required
& Bottom if non-combustible material is
used between the boiler and
compartment panels.
Both sides - 45mm
Front - 40mm
The compartment should be large enough to
house the boiler and ancillary equipment only.
5. IT SHOULD NOT BE USED AS A STORAGE
CUPBOARD.
250mm Min
950mm
600mm
200mm Min
5mm Min
20mm Min
For Servicing
Purposes
Fig. 17
Fig. 18
450mm
450mm Min
5mm Min
In Operation

4.0 Check List
9
4.1 Check List
1. If a fault develops, or is suspected, call your
Service Engineer as soon as possible.
2. Go through the following check list before you
make contact.
a) Are the gas and electricity supplies on ?
b) Is the selector switch on and set for both
Central Heating and Domestic Hot Water ?
c) Is the red “Flame Failure”reset button lit ?
If so, press the Reset Button.
d) Is the overheat indicator lit ?
If so, press the white Reset Button.
e) Is the mains water supply turned on ?
f) Are the boiler temperature controls set high
enough ?
g) Are the time clock and room thermostat
(where fitted) calling for heat ?
h) Are all the radiator valves open ?

5.0 Cleaning, Spares &
Guarantee
10
5.1 Cleaning the Outercase
The painted panels should be wiped with a damp
cloth and then dried completely. DO NOT USE
ABRASIVE CLEANING AGENTS.
5.2 Spare Parts
IMPORTANT - Only a competent person
should be used to service or repair this boiler
1. Any repairs to the boiler will usually be the
responsibility of the Installer during the
guarantee period after which spare parts may be
obtained through approved Baxi stockists if
required.
2. Quote the appliance name, model number
and where possible the part number when
ordering spares. A short parts list is included in
the Installation and Servicing Instructions.
5.3 Guarantee
1. Your Baxi Maxflow Combi WM is designed
and produced to meet all the relevant Standards.
2. Baxi UK Limited provide a 12 month
guarantee on the boiler. The guarantee operates
from the date installation is completed for the
customer who is the original user.
3. To maximise the benefit from our guarantee
we urge you to return the reply-paid guarantee
registration.
4. This does not in any way prejudice your rights
at Common Law. Such rights between the
customer and the installer or supplier from whom
the unit was purchased remain intact.
Any component or part which becomes
defective during the guarantee period as a
result of faulty workmanship or material
whilst in normal use will be repaired or
replaced free of charge.

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Baxi UK Limited manufacture a comprehensive range
of products for the domestic heating market.
Gas Central Heating Boilers
(Wall, Floor and Fireside models).
Independent Gas Fires.
Renewal Firefronts.
Gas Wall Heaters.
Solid Fuel Fires.
If you require information on any of these products,
please write, telephone or fax to the Sales Department.

Baxi UK Limited
Brownedge Road
Bamber Bridge Preston
Lancashire
PR5 6SN
www.baxi.com
After Sales Service
08706 096 096
Comp No247309 - Iss 5 - 5/01
921.431.2