Baxi MainEco Combi 24 User manual

United Kingdom
en
Combi 24-28-35 / System 18-24
User Manual
Wall Mounted Gas Condensing Boiler
Baxi MainEco Combi and System

Dear customer,
Thank you for purchasing this appliance.
Please read this manual carefully before using the product and keep it in a safe place for future reference.
In order to ensure continued safe and efficient operation we recommend that the product is regularly maintained. Our Service
and After Sales organization can assist with this.
We hope you will receive many years of satisfactory service.

Contents
1 Introduction ................................................................................................4
1.1 Symbols used .......................................................4
1.2 Abbreviations ........................................................4
1.3 General ..................................................................5
1.3.1 Manufacturer’s liability .............................................5
1.3.2 Installer’s liability .....................................................5
1.3.3 User’s liability ..........................................................6
1.4 Certifications .........................................................6
2Safety instructions and recommendations ..............................................7
2.1 Safety instructions ...............................................7
2.2 Recommendations ................................................8
2.2.1 Benchmark Commissioning Checklist .....................8
3Description ..................................................................................................9
3.1 Operating principle ...............................................9
3.1.1 Gas/air setting .........................................................9
3.1.2 Combustion .............................................................9
3.1.3 Heating and domestic hot water production ............9
3.2 Main parts ............................................................10
3.3 Clearances around the boiler ............................10
3.4 Control system ....................................................11
3.4.1 Adjustment ............................................................11
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3.5 Control panel .......................................................11
4 Operating the boiler .................................................................................12
4.1 Commissioning the boiler ..................................12
4.2 Reading the various current values ..................12
4.3 Installation shutdown .........................................13
4.4 Antifreeze protection ..........................................13
5 Checking and maintenance .....................................................................14
5.1 General instructions ...........................................14
5.2 Periodic checks ..................................................14
5.3 Filling the system ...............................................15
5.4 Bleeding the heating system .............................16
5.5 Draining the installation .....................................17
6 Troubleshooting .......................................................................................18
6.1 Error codes ..........................................................18
6.2 Incidents and solutions ......................................20
7 Technical specifications ..........................................................................21
7.1 Technical specifications ....................................21
8 Energy savings .........................................................................................22
8.1 Energy-saving advice .........................................22
8.2 Room thermostat and settings ..........................22
9 Warranty ....................................................................................................23
9.1 General ................................................................23
9.2 Warranty terms ...................................................23
9.2.1 Warranty registration, service & repair ..................23
9.2.2 Benchmark Commissioning Checklist ...................23
9.2.3 Ways to register your warranty .............................23
9.2.4 Annual service .......................................................24
10 Appendix ...................................................................................................25
10.1 User instruction card ..........................................25
Contents
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1 Introduction
1.1 Symbols used
In these instructions, various danger levels are employed
to draw the user’s attention to particular information. In so
doing, we wish to safeguard the user’s safety, highlight
hazards and guarantee correct operation of the appliance.
DANGER
Risk of a dangerous situation causing serious
physical injury.
WARNING
Risk of a dangerous situation causing slight
physical injury.
CAUTION
Risk of material damage.
Signals important information.
¼Signals a referral to other instructions or other pages
in the instructions.
1.2 Abbreviations
4LTH: Low temperature heating
4DHW: Domestic hot water
4HRU: Heat Recovery Unit
4PCU: Primary Control Unit - Electronic system to
control burner function
4SCU: Secondary Control Unit - Additional electronic
system
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1.3 General
1.3.1. Manufacturer’s liability
Our products are manufactured in compliance with the
requirements of the various applicable European
Directives. They are therefore delivered with [ marking
and all relevant documentation.
In the interest of customers, we are continuously
endeavouring to make improvements in product quality.
All the specifications stated in this document are therefore
subject to change without notice.
Our liability as the manufacturer may not be invoked in the
following cases:
4Failure to abide by the instructions on using the
appliance.
4Faulty or insufficient maintenance of the appliance.
4Failure to abide by the instructions on installing the
appliance.
1.3.2. Installer’s liability
The installer is responsible for the installation and
commissioning of the appliance. The installer must
respect the following instructions:
4Read and follow the instructions given in the manuals
provided with the appliance.
4Carry out installation in compliance with the prevailing
legislation and standards.
4Perform the initial start up and carry out any checks
necessary.
4Explain the installation to the user.
4If a maintenance is necessary, warn the user of the
obligation to check the appliance and maintain it in
good working order.
4Give all the instruction manuals to the user.
Baxi MainEco Combi and System 24 - 28 - 35 / 18 -24 1. Introduction
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1.3.3. User’s liability
To guarantee optimum operation of the appliance, the
user must respect the following instructions:
4Read and follow the instructions given in the manuals
provided with the appliance.
4Call on qualified professionals to carry out installation
and initial start up.
4Get your installer to explain your installation to you.
4Ensure the Appliance is serviced in accordance with
the manufacturer’s instructions by a suitable qualified
person.
4Keep the instruction manuals in good condition close
to the appliance.
This appliance is not intended to be used by persons
(including children) whose physcial, sensory or mental
capacity is impaired or persons with no experience or
knowledge, unless they have the benefit, through the
intermediary of a person responsible for their safety, of
supervision or prior instructions regarding use of the
appliance. Care should be taken to ensure that children
do not play with the appliance.
If the mains power lead is damaged it must be replaced
by the original manufacturer, the manufacturer’s dealer or
another competent person to prevent hazardous
situations.
1.4 Certifications
CE identification no PIN 0063CM3019
NOx classification 5 (Standards EN)
Type of connection (Flue gas outlet) C13, C33, C53
Gas Council number MainEco Combi 24: 47–075–93
MainEco Combi 28: 47–075–94
MainEco Combi 35: 47–075–95
MainEco System 18: 41–470–13
MainEco System 24: 41–470–14
1. Introduction Baxi MainEco Combi and System 24 - 28 - 35 / 18 -24
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2 Safety instructions and
recommendations
2.1 Safety instructions
DANGER
If you smell gas:
1. Do not use a naked flame, do not smoke, do not
operate electrical contacts or switches ( doorbell,
light, motor, lift, etc..).
2. Shut off the gas supply.
3. Open the windows.
4. Evacuate the premises.
5. Call your fitter.
DANGER
If you smell flue gases:
1. Switch the appliance off.
2. Open the windows.
3. Evacuate the premises.
4. Call your fitter.
WARNING
Depending on the settings of the appliance:
4The temperature of the flue gas conduits may exceed
60°C.
4The temperature of the radiators may reach 85°C.
4The temperature of the domestic hot water may reach
65°C.
CAUTION
Do not neglect to service the appliance:
4For completely safe and optimum operation, you
must have your boiler regularly serviced by an
approved installer.
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2.2 Recommendations
WARNING
Only qualified professionals are authorised to work on the
appliance and the installation.
4Regularly check the water pressure in the installation (minimum
pressure 0.8 bar, recommended pressure between 1 and 2 bar).
4Keep the appliance accessible at all times.
4Never remove or cover labels and rating plates affixed to the
appliance. Labels and rating plates must be legible throughout the
entire lifetime of the appliance.
4The appliance should be on Summer or Antrifreeze mode rather
than switched off to guarantee the following functions:
-Anti blocking of pumps
-Antifreeze protection
2.2.1. Benchmark Commissioning Checklist
Please ensure that the installer has fully completed the Benchmark
Checklist on the inside back pages of the installation instructions
supplied with the product and that you have signed it to say that you
have received a full and clear explanation of its operation. The
installer is legally required to complete a commissioning checklist as
a means of complying with the appropriate Building Regulations
(England and Wales).
All installations must be notified, by the installer, to Local Area
Building Control either directly or through a Competent Persons
Scheme. A Building Regulations Compliance Certificate will then be
issued to the customer who should, on receipt, write the Notification
Number on the Benchmark Checklist.
This product should be serviced annually to optimise its safety,
efficiency and performance. The service engineer should complete
the relevant section of the Benchmark Service Record in the
Installation & Service manual after each service.
The completed Benchmark Checklist & proof of annual servicing
(where applicable) will be required in the event of any warranty work.
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3 Description
3.1 Operating principle
3.1.1. Gas/air setting
The casing fitted to the boiler is also used as an air box. Air is sucked
in by the fan and gas injected into the venturi by the fan intake. The
fan rotation speed is set according to the settings parameters, the
thermal energy requirement and the temperatures measured by the
temperature sensors. The gas and air are mixed in the venturi. The
gas/air ratio ensures that the quantities of gas and air are adjusted to
each other. This provides optimum combustion on the entire output
range. The gas/air mixture is fed into the burner on top of the
exchanger.
3.1.2. Combustion
The burner heats the heating water circulating in the heat
exchanger. At a return temperature lower than around 55°C, the flue
gases cool down to a temperature lower than the dew point, thus
causing the condensation of the water vapour contained in the flue
gases in the lower section of the heat exchanger. The heat released
during this condensation process (the latent heat or condensing heat)
is also transferred to the heating water. The cooled combustion gases
are evacuated via the combustion gas outlet flue. The condensation
water is evacuated via a condensate trap.
3.1.3. Heating and domestic hot water production
On combi boilers, an integrated plate exchanger heats the domestic
water. A 3-way valve determines whether the heated water is fed into
the heating system or the plate exchanger. A pick-up sensor signals
that a hot water tap is being opened. This signal is transmitted to the
control panel, which then switches the 3-way valve to the hot water
position and trips the heating pump. The 3-way valve is spring-loaded
but only consumes electricity when it switches to another position.
The heating water reheats the domestic water in the plate
exchanger. In comfort mode, if there is no hot water draw-off, the
boiler handles the periodic reheating of the plate exchanger. Any
limescale particles are kept out of the plate exchanger by a self-
cleaning water filter (self-cleans once every 76 hours).
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3.2 Main parts
1Flue gas outlet/Air intake (Combustion air/flue gas
adapter 60/100)
2Casing/air box
3Outlet for measuring combustion gases
4Ignition/ionization electrode
5Flue gas discharge pipe
6Gas/air system with a fan, gas block and automatic burner
unit
7Air intake silencer
8Plate heat exchanger (DHW) (Only for Combi models)
9Connection box
10 Condensate trap
11 Circulation pump
12 3-way valve
13 Primary heat exchanger
14 Expansion vessel
15 Automatic air vent
3.3 Clearances around the boiler
(1) Clearance when operating
(2) Clearance for maintenance
T004783-A
3
5
6
7
9
8
13
12
14
15
11
10
1
2
4
R000698-A
368 5
1000 (2)
364
≥ 200
5
≥ 250
554
5 (1)
3. Description Baxi MainEco Combi and System 24 - 28 - 35 / 18 -24
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3.4 Control system
3.4.1. Adjustment
The power of the boiler can be adjusted in the following ways:
4On/Off setting
The output between the minimum and maximum values varies
based on the heating flow set point temperature.
4Adjustable control
The output between the minimum and maximum values varies
based on the heating flow temperature determined by the
modulating control system.
3.5 Control panel
MainEco Combi 24 - 28 - 35
1Domestic hot water temperature rotary knob
2Heating water temperature rotary knob
3Sweep key B and Status signals
4RESET-button and on/off signal
MainEco System 18 - 24
1No function
2Heating water temperature rotary knob
3Sweep key B and Status signals
4RESET-button and on/off signal
The instrument panel for the connection box has 2 push buttons with
signals. The signals provide information about the operating condition
of the boiler. The RESET button lights up green when the boiler is
connected to the mains. The status signal for the B button can flash
in a range of colours and at different frequencies. The meaning of
these signals can be found in the User instruction card supplied with
the boiler. ¼See also: "User instruction card", page 25
CAUTION
The instruction card must be slid underneath the
connection box after the boiler installation or use of the
card.
The instrument panel for the connection box also has 2 rotary
knobs. The N rotary knob can be used to set the temperature of the
domestic hot water. The D rotary knob can be used to set the
maximum flow temperature of the heating water. The heating/
domestic hot water function can be switched off by turning the rotary
knob to position off.
T002247-D
321 4
R000714-A
321 4
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4 Operating the boiler
4.1 Commissioning the boiler
1. Check the water pressure in the heating system.
If the water pressure is lower than 0.8 bar, more water
should be added. If necessary, top up the water level in the
heating system (recommended hydraulic pressure
between 1 and 2 bar).
¼See chapter: "Filling the system", page 15
2. Open the gas valve on the boiler.
3. Turn the boiler on.
4. The boiler will begin an automatic venting-programme (which lasts
approx. 4 minutes) and will do this every time the power supply is
isolated. Both push buttons on the instrument panel light up green
during the venting cycle.
The current operating condition of the boiler is shown by the status
signal on the instrument panel. The status signal for the B button
can flash in a range of colours and at different frequencies. The
meaning of these signals can be found in the User instruction card
supplied with the boiler.
See also:
¼ "User instruction card", page 25
¼ "Error codes", page 18
4.2 Reading the various current values
Boiler status information can be read using a suitable controller. The
following current values can be read off the information menu Q:
4State.
4Sub-status.
4Flow temperature (°C).
4Return temperature (°C).
4Calorifier temperature (°C).
4Outside temperature (°C) (Only with an outside temperature
sensor).
4Solar boiler temperature (°C).
4Ionization current (µA).
4Fan speed in rpm.
4Water pressure (bar (MPa)).
4Supplied relative heat output (%).
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4.3 Installation shutdown
If the central heating system is not used for a long period, we
recommend switching the boiler off.
4Switch off the boiler electrical power supply.
4Shut off the gas supply.
4Ensure that the boiler and system are protected against frost
damage.
4.4 Antifreeze protection
CAUTION
Drain the boiler and central heating system if you are not
going to use your home or the building for a long time and
there is a chance of frost.
Set the temperature control low, for example at 10°C.
To prevent radiators and the system from freezing in rooms where
there is a risk of frost (e.g. a garage or storage room), a frost
thermostat or outside sensor can be connected to the boiler.
CAUTION
4The antifreeze protection does not function if the
boiler is switched off.
4The integrated protection system only protects the
boiler, not the installation.
4Open the valves on all radiators connected to the
heating system
4If the boiler has been placed in a room at risk of frost,
the condensate drain and condensate trap should
preferably be protected against freezing with a frost
protection cable.
When the heating water temperature in the boiler falls by too much,
the integrated protection system in the boiler starts up. This protection
functions as follows:
4If the water temperature is lower than 7°C, the heating pump starts
up.
4If the water temperature is lower than 4°C, the boiler starts up.
4If the water temperature is higher than 10°C, the boiler shuts down
and the circulation pump continues to run for a short time.
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02092014 - 7621607-02 13

5 Checking and maintenance
5.1 General instructions
WARNING
4Maintenance operations must be done by a qualified
engineer.
4An annual inspection is compulsory.
4Only original spare parts must be used.
4Carry out the inspection and standard maintenance operations
once a year.
4Carry out specific maintenance operations if necessary.
CAUTION
4Maintenance operations must be done by a qualified
engineer.
4We recommend taking out a maintenance contract.
4Only original spare parts must be used.
5.2 Periodic checks
4Check the water pressure in the installation.
If the water pressure is lower than 0.8 bar, more water
should be added. If necessary, top up the water level in the
heating system (recommended hydraulic pressure
between 1 and 2 bar).
¼See chapter: "Filling the system", page 15.
4Carry out a visual check for the presence of any water leaks.
4Open and close the radiator valves several times a year (this
prevents the valves from seizing up).
4Clean the outside of the boiler using a damp cloth and a light
detergent.
CAUTION
Only a GasSafe Registered Installer is authorised to clean
the inside of the boiler.
1
2
3
4
T000181-B
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5.3 Filling the system
Topping up without a refilling device:
1. Use the pressure gauge to check the water pressure in the heating
system.
If the water pressure is lower than 0.8 bar, more water
should be added. If necessary, top up the water level in the
heating system (recommended hydraulic pressure
between 1 and 2 bar).
2. Open the valves on all radiators connected to the heating system.
3. Set the room thermostat to as low a temperature as possible.
4. Wait until the temperature drops below 40°C and the radiators
seem cold before filling the central heating system.
5. To fill with water, use a filling tube with two tap connections, a rag
and a bleed key.
6. Connect the filling tube to a (cold) water tap.
7. Eliminate the air from the filling tube. Slowly fill the tube with
water. Hold the end of the tube up, above a bucket. Turn off the
tap as soon as water runs out of the pipe.
8. Unscrew the plug from the filling/draw-off valve.
The filling/draw-off valve is not necessarily located next to
the boiler.
9. Attach the tube to the filling/draw-off valve. Firmly tighten the nut
on the filling tube.
10.Open the filling/draw-off valve on the heating system.
11.Open the running water tap.
12.Use the pressure gauge to check the water pressure in the heating
system.
13.Close the water tap when the water pressure reaches 2 bar.
14.Close the filling/draw-off valve on the heating system. Leave the
tube on the filling/draw-off valve until the air is purged from the
installation.
When water is added, air gets into the heating system:
4Degas the installation.
4After the air has been vented, the water pressure can
drop below the required level.
4Use the pressure gauge to check the water pressure
in the heating system.
4If the water pressure is lower than 0.8 bar, more water
should be added.
15.After filling the installation, switch the boiler on.
Filling and bleeding the installation 2 times a year should
be sufficient to obtain an adequate hydraulic pressure. If it
is often necessary to top up the installation with water,
contact your fitter.
AD-3000483-A
14
10
9
8
7
6
5
4
3
1
2
3
4
2
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02092014 - 7621607-02 15

5.4 Bleeding the heating system
It is essential that you bleed any air in the heating system to prevent
the annoying noises likely to be produced during heating or when
tapping water. To do this, proceed as follows:
1. Open the valves on all radiators connected to the heating system.
2. Set the room thermostat as high as possible.
3. Wait until the radiators are hot.
4. Switch the boiler off.
5. Wait around 10 minutes until the radiators are cold.
6. Bleed the radiators. Start with the lower floors.
7. Open the bleed connection using the bleed key provided whilst
keeping a rag pressed against the connection.
8. Wait until water comes out of the bleed valve and then close the
bleed connection.
CAUTION
The water may still be hot.
9. Switch on the boiler. A vent cycle of a duration of around 3 minutes
is carried out automatically.
10.After venting, check whether the pressure in the installation is still
sufficient.
If the water pressure is lower than 0.8 bar, more water
should be added. If necessary, top up the water level in the
heating system (recommended hydraulic pressure
between 1 and 2 bar).
¼See chapter: "Filling the system", page 15
11.Set the room thermostat or the regulator.
R000712-A
87
A
C
B
6
5
4
3
2
1
2
3
4
1
11
5. Checking and maintenance Baxi MainEco Combi and System 24 - 28 - 35 / 18 -24
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5.5 Draining the installation
It may become necessary to empty the water from the heating system
when the radiators have to be replaced, should there be a major water
leak or a risk of frost. To do this, proceed as follows:
1. Open the valves on all radiators connected to the heating system.
2. Switch off the boiler electrical power supply.
3. Wait around 10 minutes until the radiators are cold.
4. Connect an evacuation hose to the plug located at the lowest
level. Place the end of the hose in a discharge sump or in a place
where the water discharged from the valve can not do any
damage.
5. Open the filling/draw-off valve on the heating system. Vent the
heating installation.
WARNING
The water may still be hot.
6. When no more water comes out of the drainage plug, close the
drainage valve.
After draining the concentration of system corrosion
inhibitor and anti-freeze may become excessively diluted -
seek advice from your installer.
R000730-A
5
3
2
1
2
3
4
1
4
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02092014 - 7621607-02 17

6 Troubleshooting
6.1 Error codes
In the event of a fault, the status signal for the B button flashes
red. The meaning of the error codes is given in the error table:
Status signals Description Code(1)
Error code 1
(1 times red signal) Sensor error e[02 / e[03 / e[04 / e[05 / e[06 / e[07 / e[08 /
e[09 / e[10 / e[11 / e[35
Error code 2
(2 times red signal) Overheat temperature protection e[12 / e[41
Error code 3
(3 times red signal) Ignition fault e[14 / e[16 / e[36
Error code 4
(4 times red signal) Fan fault e[34
Error code 5
(5 times red signal) Parameter error e[00 / e[01
Error code 6
(6 times red signal) Miscellaneous e[17 / e[37 / e[38 / e[39 / e[40 / e[41
(1) The code can be read using a suitable controller.
If one of the above mentioned error codes is shown, proceed as
follows:
4Check the water pressure in the heating system.
-The water pressure is higher than 0,8 bar. Degas the
installation.
-The water pressure is lower than 0,8 bar. Fill the system with
clean tap water (advised water pressure is between 1,5 and 2
bar).
4Check that the gas valve is fully opened.
-Open the gas valve if it is closed.
Press the J key for 5 seconds: The status signals will
flash red quickly and the boiler will start its reset
procedure. The boiler will also start an automatic venting
cycle lasting around 4 minutes. If the error code continues
to display, contact the installer.
Before contacting the installer. Note the following information:
4Error code
4Boiler type
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