Baxi Slim 1.230 FiN Use and care manual

Gas boilers with a cast-iron base,
sealed chamber, automatic ignition
and electronic fl ame modulation
User and Installer Manual
BAXI S.p.A., one of the leading European companies in the production of heating and hot-water appliances for household use
(wall-mounted gas boilers, free-standing boilers and electric water heaters) has obtained CSQ certifi cation in accordance with
UNI EN ISO 9001 standards.
This certifi cation confi rms that the Quality System of
BAXI S.p.A. in Bassano del Grappa, where this boiler was manufactured,
satisfi es the strict UNI EN ISO 9001 standard covering all aspects of company organisation, manufacturing and distribution.
UNI EN ISO 9001
CERTIFICAZIONE DEI SISTEMI
QUALITA' DELLE AZIENDE
Fi - FiN

Dear Customer,
We are sure your new boiler will comply with all your requirements.
Purchasing one of the BAXI products satisfies your expectations: good functioning, simplicity
and ease of use.
Read these instructions fully before installing or using the appliance: you can find useful
information, which will help you to run your boiler correctly and efficiently.
BAXI boilers bear the CE mark in compliance with the
essential requirements as laid down in the following
Directives:
- Gas Directive 90/396/CEE
- Performance Directive 92/42/CEE
- Electromagnetic Compatibility Directive 89/336/CEE
- Low voltage Directive 73/23/CEE
Do not leave any parts of the packaging (plastic bags, polystyrene, etc.) within children’s reach as they are a potential source of danger.

3
1 General Information pag. 4
2 Instruction prior to installation 4
3 Instruction prior to commissioning 4
4 Commissioning of the boiler 5
5 Room temperature adjustment 6
6 Turning off the boiler 6
7 Filling the boiler 6
8 Emptying the boiler 6
9 Prolonged standstill of the system 6
10 Safety devices indicators – meaning – 7
11 Gas conversion 7
12 Servicing instructions 7
CONTENTS
Instructions
pertaining to the user
Instructions
pertaining to the installer
1 Overall dimensions 8
2 General information 9
3 Instructions prior the installation 10
4 Installation 10
5 Electrical connection 16
6 Electrical diagram 17
7 Room thermostat connection 18
8 Connecting a programming timer 19
9 Domestic hot water storage tank connection 20
10 Connection of the external probe 24
11 Connection of the climatic regulator QAA73 25
12 Air vent and release of the pump 27
13 Regulation on the electronic card (PCB) 27
14 Gas conversion 28
15 Table of gas consumption and injectors 29
16 Regulation and safety devices 30
17 Check of combustion parameters 30
18 Specifications of flow rate/head at the plate 31
19 Hydraulique resistance performances 31
20 How to service and clean the boiler 31
21 Technical data 32

4
2. Instructions prior to
installation
This boiler is designed to heat water at a lower than boiling temperature
at atmospheric pressure.
The boiler must be connected to a central heating system and to a DHW
distribution system, in compliance whit its performances and heat
output.
Have the boiler installed by a Qualifi ed Service Engineer and ensure the
following operations are accomplished:
• Accurate purging of the whole pipe work in order to remove any
deposits.
• Careful checking that the boiler is fi t for operation with the type of
gas available. For more details see the notice on the package and the
label on the appliance itself.
• Careful checking that the fl ue terminal draft is appropriate, that the
terminal is not obstructed and that no other appliance exhaust gases
are expelled through the same fl ue duct, unless the fl ue is especially
designed to collect the exhaust gas coming from more than one ap-
pliance, in conformity whit the laws and regulations in force.
3. Instructions prior to
commissioning
First commissioning of the boiler must be carried out by an authorized
Service Engineer. Ensure the following operations are carried out:
• Compliance of boiler parameters with (electricity, water, gas) supply
systems settings.
• Compliance of installation with the laws and regulations in force.
• Appropriate connection to the power supply and grounding of the
appliance.
Electrical safety of the appliance is only guaranteed by correct groun-
ding, in compliance whit the applicable laws and regulations.
The boiler must be electrically connected to a 230 V single-phase +
earth mains with the three-wire cable supplied, observing the polarity
LIVE (L) - NEUTRAL (N).
Use a double-pole switch with a contact separation of at least 3mm
In both poles.
In case you replace the power supply cable fi t a HAR H05 VV-F 3x1
mm2 cable with an 8 mm diameter max.
The following instructions give important information for the commission
and the use of the device.
The remarks and technical instructions, addressed to Service Engineers
to help them to carry out a faultless installation, will be contained in the
second part of this manual.
1. General description
The SLIM boilers are high-effi ciency gas boilers with a cast-iron base,
sealed combustion circuit, forced ventilation, direct burner ignition,
electronic ionizing fl ame control and electronic modulation of the gas
fl ow rate, to be used as generators in single-family hot-water heating
systems.
The SLIM series is made in two versions.
Instructions pertaining to the user
TABLE I
Ia: FiN models without plumbing accessories
boiler nominal heating reduced heating num. exchanger
models power power elements
kW kW
1.230 FiN 22,1 11,8 4
1.300 FiN 29,7 14,9 5
Fi models with plumbing accessories
boiler nominal heating reduced heating num. exchanger
models power power elements
kW kW
1.230 Fi 22,1 11,8 4
1.300 Fi 29,7 14,9 5

5
4. Commissioning of the
boiler
To have access to the control system of the boiler, open the transparent
panel which covers the control panel. The panel rotates down.
To open the upper door of the boiler pull on its upper corners so that the
door will be released from the outer casing.
To correctly light the boiler proceed as follows:
• Provide power supply to the boiler;
• Open the gas cock;
• Verify that the system is full of water and the pressure is the right one
(see point 7);
• Turn the selector switch (ref. 1 fi gure 1) to set the boiler on winter
operation.
• Regulate the room thermostat (if present) at the desired temperatu-
re.
• Set the Central Heating regulation knob (ref. 2 fi gure 1) in order to
have the boiler at the desired temperature.
For a better energy saving we suggest you to set the regulation knobs in
the “COMFORT” position, environment conditions permitting.
Important: when selector is set to Winter (ref. 1 fi gure 1) you have
to wait few minutes every time the heating regulation device switches
off the burner (ref. 2 fi gure 2). If you want the burner to switch on im-
mediately, turn the selector in position (O) and then switch it again, in
winter position.
Warning: During fi rst commissioning, until the air inside the gas pipes
is not released, the burner may fail to light immediately and this may
cause a blockage of the boiler. Under such conditions we recommend
you to repeat the ignition procedure until gas is delivered to the burner,
briefl y setting knob (1) to position (ref. 1 fi gure 1).
4.1 Operation with Water Storage Tank Unit
The boiler water adjustment knob (Ref. 3 Figure 1) is only active when
there is a Tank unit. In this case it is possible to adjust the domestic
hot water temperature by turning the knob onto the required hot water
setting.
With the summer/winter selector set to winter mode , when the
water of the tank has reached the selected temperature, the boiler works
automatically for the heating system (priority is given to the domestic
hot water supply).
It is possible to exclude the sanitary mode just setting the knob (ref. 3
fi gure 1) to the minimum value, that corresponds to the anti-frost function
of the tank.
With the summer/winter selector set to summer mode , the burner is
alight and the tank’s pump works only when the temperature of the water
inside the tank is less than the value set with the DHW knob.
Picture 1: control panel of the boiler
Key:
1. Summer-Winter-Reset selector
2. Central Heating water regulation knob
3. DHW water regulation knob
4. Voltage presence indicator
5. DHW production mode indicator
6. Central heating mode indicator
7. Flame presence indicator
8. Gas block indicator
9. Overheating indicator
10. Blocked fl ue pressostat indicator
11. Blocked pressostat indicator (option)
12. DHW probe failure indicator options
13. Central heating probe failure indicator
14. Place for programming timer
8-9-10-11-12-13
Central heating thermometer
The domestic hot water function is only active
with the boiler unit
0401_2101
1
2
4
5
6
7
8
9
10
11
12
13
14
3

6
8. Emptying the boiler
8.1. Emptying the boiler
To empty the boiler use the tap you find on the right side of the cast-iron
exchanger after opening the upper door of the boiler and the door of
room sealed.
To achieve this operation connect the tap with a flexible pipe to a drainpipe
as it is here described:
• Connect the flexible pipe to the hose adapter of the drain tap of the
boiler.
• Unscrew the nut of the drain tap.
• Open the draining valves of the radiators, starting, from the ones which
are in the upper position.
It is absolutely forbidden to empty the boiler through its safety
valve.
9. Prolonged standstill of
the system -
Frost protection
It is wise to avoid draining the entire heating system since frequently
changing the water leads to harmful scale getting deposited in the boiler
and in the heating elements.
If the heating system is not to be used during the winter, and when there
is a risk of freezing, it is advisable to mix the water in the system with
suitable antifreeze solutions intended for this specific use (e.g., propylene
glycol associated with incrustation and corrosion inhibitors).
The boiler is equipped with an “antifreeze” function that, with system
delivery temperatures under 5 °C, makes the burner operate until the
delivery reaches a temperature of 30 °C.
The frost protection function is enabled if:
• Electrical supply to the boiler is on;
• Selector (1) is not in position (0);
• There is gas;
• The system water pressure is as required;
• The boiler is not blocked.
When there is a DHW tank the Boiler also has an “antifreeze” function
for the domestic hot water. The electronic control will prevent it from
falling under 5°C.
5. Room temperature
adjustment
The system must be equipped with a room thermostat (see the relevant
regulations) to control the temperature in the rooms.
In case of temporary absence of a room thermostat, it will be possible,
during initial lighting, to control the room temperature operating on
the boiler water temperature regulation device (ref. 2 figure 1): in these
conditions the central heating pump will continuously operate.
To increase the temperature turn the knob clockwise and anticlockwise
to decrease it.
6. Turning off the boiler
To turn off the boiler correctly, follow the instructions described here
below:
PARTIAL TURN OFF
• Turn the selector switch (ref. 1 figure 1) on (0) and verify that the
voltage lamp switches off (ref. 4 figure 1): in this way you cut off the
electrical input to the boiler.
TOTAL TURN OFF
• Close the gas cock if the boiler will not operate for a long time.
7. Filling the boiler
Important: Regularly check that the pressure displayed by the pressure
gauge of the installation (for FiN models) or by the pressure gauge of
the boiler (for Fi models) is 0.5 to 1 bar with the boiler stopped. In case
the pressure is lower than 0,5 bar, fill the system by means of the filling
tap that it must be present in the heating circuit.
We recommend you to carry out the filling operation very slowly in order
to let off the air.
Do not fill the system when the boiler is still warm.
In case pressure drops occur frequently, the boiler has to be checked by
a qualified Service Engineer.

7
11. Gas conversion
These boilers are adjusted for natural gas but can be converted to work
with LPG.
Any gas conversion must be carried out by Qualified Service Engineer.
12. Servicing instructions
To maintain an efficient and safe operation of your boiler, it has to be
checked by a Qualified Service Engineer at the end of every season.
Careful servicing will ensure economical operation of the system.
Do not clean the outer casing of the appliance with abrasive, aggressive
and/or easily flammable cleaners (i.e. gasoline, alcohol, and so on).
Always isolate the electrical supply to the appliance before cleaning it.
The lights 8÷13 display the temperature of the water in the central heating
system (when not blinking).
The flashing warning (10) no draught, is activated by an air - flue gas
pressure switch in the event of:
• total or partial obstruction of the flue outlet or duct;
• fan jammed;
In these conditions the boiler stays on standby (burner off) and only after
removing the cause of the warning will normal operation be automati-
cally restored.
The blinking of light (9) signs the safety thermostat operation and
indicates that the water of the central heating circuit has reached very
high levels of temperature due to an anomaly in the boiler’s regulation
devices.
In this condition the boiler blocks and the light (9) continues to blink.
Once you have solved the problem, to re-establish the normal working
condition, rotate the knob of the selector (1) temporarily in position
, after waiting for a lowering of at least 20°C of the heating flow water
temperature.
When the light (9) is blinking, the light (8) will be blinking as
well.
It is forbidden to disable these safety devices
The gas block light (8) starts to blink when a lack of gas or an incom-
plete ignition of the burner occurs.
In this condition the boiler stays in a safety block.
To re-establish the normal working condition of the boiler, rotate the
selector knob (1) temporarily in position .
In case of repeated operations of these safety devices, contact the
Qualified Service Engineer.
oce_010605_0300
1. Summer-Winter-Reset selector
4. Voltage presence indicator
5. DHW production mode indicator
6. Central heating mode indicator
7. Flame presence indicator
8. Gas block indicator
9. Overheating indicator
10. Blocked flue indicator
11. Blocked pump indicator (not active)
12. DHW temperature probe failure indicator
13. Central heating temperature probe failure indicator
8-9-10-11-12-13
Central heating thermometer
10. Safety device indicators
- meaning
13 12 11 10 9 8
7 6 5 4 1

8
The following remarks and instruction are addressed to Service Engineers
to help carry out a faultless installation.
Instructions regarding lighting and operation of the boiler are contained
in the ‘Instructions pertaining to the user’s section”.
CAUTION:
- When moving the unfastened appliance, the door of the instrument
panel may accidentally open and get damaged by knocking against
other objects. If installation requires special handling of the appliance,
it is recommended to secure it with adhesive tape.
- The parts of the packing (plastic bags, polystyrene, etc.) must not be
left within reach of children as they are potential sources of danger.
1. Overall dimensions
1.230 FiN, 1.300 FiN Models
010917_1000
C
B
A
Instructions pertaining to the installer

9
2. General information
This boiler must be installed by a qualifi ed service engineer.
Important:
• Connect the inlet gas pipe of the boiler to the gas distribution network
using a metallic pipe and install a gas cock before the boiler.
• The boiler can be used with any type of radiators, convectors, single
or double pipe. Sections of the system will be, in any case, calculated
according to the normal methods, keeping in mind of the hydraulique
resistance performances (see paragraph 18).
• In case of external installation, avoid that the boiler is directly exposed
to atmospheric agents as wind, water, frost, which can prejudice
the operation and the safety of the boiler. Non-observance of such
TABLE I
FiN models without plumbing accessories
boiler dimensions connections water cont.
models height H width depth L delivery return gas
mm mm mm A B C l
1.230 FiN 850 350 542 3/4” m 3/4” m 1/2” m 11,8
1.300 FiN 850 350 622 3/4” m 3/4” m 1/2” m 14,6
TABLE II
Fi models with plumbing accessories
boiler dimensions connections water cont.
models height H width depth L delivery return gas DHW tank outlet
mm mm mm A B C D l
1.230 Fi 850 350 596 3/4” m 3/4” m 1/2” m 3/4” F 11,8
1.300 Fi 850 350 676 3/4” m 3/4” m 1/2” m 3/4” F 14,6
1.230 Fi, 1.300 Fi models
010917_1100
A
B
C
D
prescription involves the immediate loss of the guarantee. For this
reason we suggest the creation of a technical space, protected from
bad weather.
• Do not leave any parts of the packaging (plastic bags, polystyrene,
etc.) within children’s reach as they are a potential source of danger.
• Initial ignition of the boiler must be carried out by Qualifi ed Service
Engineer.
Non-observance of such prescription involves the immediate loss of the
guarantee.

10
oce.9803100601
Figure 1: Hydraulic diagrams for multi-zones heating circuit
MULTI-ZONES INSTALLATION WITH PUMPS
MULTI-ZONES INSTALLATION WITH VALVES
RETURN MANIFOLD/COLLECTOR
BOILER RETURN
BOILER RETURN
RETURN MANIFOLD/COLLECTOR
NO-RETURN VALVES
ZONE VALVES
ZONE PUMPS
FLOW MANIFOLD/COLLECTOR
BOILER FLOW
BOILER FLOW
ADJUSTABLE BY-PASS
FLOW MANIFOLD/COLLECTOR
3. Instruction prior the
installation
This boiler is designed to heat water at lower than boiling temperature at
atmospheric pressure. The boiler must be connected to a central heating
system in compliances and heat output.
Ensure the following operations are carried out:
• Careful washing of all the pipes of the system to remove possible
threat or welding residual and solvents.
• Careful checking that the boiler is fit for operation with the type of
gas available. For more details see the label on the packaging and the
serial number label on the appliance.
• Careful checking that, in case the flue has been connected to pre-exi-
sting flue ducts, thorough cleaning has been carried out in that residual
combustion products may come off during operation of the boiler and
obstruct the flue duct thus engendering dangerous situations.
4. Installation
After determining the exact location of the boiler, installation should be
performed taking account in particular of easy maintenance (the front
door must open).
To evaluate the weight the boiler exerts on the floor it is necessary to take
account of the weight of the water too (see table I or II).
The floor must not be made of flammable materials. If necessary, insert
a panel made of non-flammable, insulating material under the bottom
of the boiler.
4.1. Connecting to the Heating System
Install the heating system starting from the position of the connections
(dimensions and connections are given in table I or II). It is advisable to
install two shut-off cocks on the heating circuit delivery and return lines
so it is possible, in the event of major work, to work without having to
drain the entire heating system.
In addition, it is necessary to install an automatic loading unit and three-
piece joints, on both the water and gas connections.
The FiN models have no expansion tank and safety valve; these de-
vices must be present in the system and suitably sized for the heating
capacity and the capacity of the system itself.
Zone systems equipped with motorized valves must have a bypass con-
nection between the boiler delivery and return with an adjustable overflow
valve in between (the bypass is not necessary in systems equipped with
zone pumps).
The boiler is drained by using the drain cock on the right of the cast-iron
shell (remove the panel of sealed room).

11
4.3.1 coaxial (concentric) inlet - outlet duct
This type of duct can be used to discharge fl ue gases and draw in air for
combustion both outside the building and in LAS-type fl ues.
The 90° coaxial bend enables connecting the boiler to the inlet - outlet
ducts in any direction since rotation is possible through 180°. It can also
be used as an additional bend in combination with the coaxial duct or
45° bend.
The boiler is supplied with a diaphragm for concentric pipes.
(*) The concentric diaphragm should only be inserted when the length
of the outlet duct is less than 1 metre.
When discharging outside, the inlet - outlet duct must protrude from the
wall by at least 18 mm to permit positioning the aluminium rose and
sealing it in order to prevent moisture getting inside.
max reduction reduction fl ue external
outlet duct length in length in length terminal duct
type of ducts without terminal to insert to insert diameter diameter
90° bend 45° bend
coaxial 5 m 1 m 0,5 m 100 mm 100 mm
twin horizontally 10 m 0,5 m 0,25 m - 80 mm
twin vertically 6 m 0,5 m 0,25 m 133 mm 80 mm
oce.9405030833
Joint
Diaphragm (concentric) (*)
Concentric union
Flexible sleeve
4.2 Gas connection
The gas installation and commissioning must be performed by a special-
ized technician in compliance with current regulations.
Connect the boiler gas supply pipe to the gas mains by means of a metal
pipe, inserting a stopcock upstream from the boiler.
The dimensions and height of the boiler’s gas pipe connection are given
in table I or II.
4.3 Installing the inlet - outlet ducts
SLIM Fi forced fl ow gas boilers can be installed easily and fl exibly thanks
to the accessories supplied, which are described further on.
The boiler is originally fi tted for connection to a vertical or horizontal,
coaxial inlet - outlet duct. Thanks to the splitter accessory it is possible
to use separate ducts too.
Only accessories supplied by the manufacturer must be used for
installation!

12
The minimum slope of these ducts towards the outside must be 1 cm
per metre in length.
oce_010621_0300 oce_011009_0100
Adding a 90° bend shortens the total length by 1 metre.
Adding a 45° bend shortens the total length by 0.5 metres.
oce_010621_0500
L max = 4 m
oce_010621_0700 oce_010621_0800
(L1+L2) max = 3 m
oce_010621_0600
examples of installation with horizontal ducts
MINIMUM SLOPE 1 cm per metre (down towards
the outside to drain off condensation)
(L1+L2) max = 3 m
(L1+L2+L3) max = 3 m
view from above
view from above
view from above
view from
above

13
oce_010621_0900
oce_010621_1000
oce_010621_1100
examples of installation with LAS-type fl ues examples of installation with vertical ducts
Installation can be performed either with a pitched roof or with a
fl at roof using the stack and the special tile and sheath available on
request.
For more detailed instructions on how to fi t the accessories, please
refer to the technical notes provided with the accessories.
4.3.2 twin pipe ducts
This type of duct can be used to discharge fl ue gases both outside the
building and in single fl ues. The air for combustion can be drawn in at
different places to those for discharge.
The splitter is an accessory comprising an exhaust reduction coupling
(100/80) and a shutter air intake coupling.
The seal and the screws of the air intake coupling are the ones re-
moved beforehand from the plug.
For more detailed instructions on how to fi t this accessory, please refer
to the technical notes provided with it.
L max = 4 m (L1+L2) max = 3 m
L max = 4 m L max = 4 m
(L1+L2) max = 3 m L max = 3,5 m

14
Air register adjustment for split outlet
This register needs to be adjusted to optimize efficiency and combus-
tion parameters. By turning the air intake coupling you can adjust the
excess air appropriately according to the total length of the ducts for
the combustion air intake and outlet.
The air intake coupling must be fitted with the pointer facing the
inside of the boiler (see figure).
For better optimization it is possible, using an analyzer for the prod-
ucts of combustion, to measure the content of CO2 in the flue gases
at the highest heating capacity and gradually adjust the air register in
order to obtain a CO2 measurement of:
• 6.5% with natural gas G.20
• 7% with liquid gas G.30-G.31
The 90° bend enables connecting the boiler to the inlet and outlet ducts
in any direction since rotation is possible through 180°. It can also be
used as an additional bend in combination with the duct or 45° bend.
Adding a 90° bend shortens the total length by 0.5 metres.
Adding a 45° bend shortens the total length by 0.25 metres.
0004191400
oce_011009_0200
Figure: Air register adjustment
opening
POSITION •• (L1+L2) max = 2 m
POSITION ••• (L1+L2) max = 20 m
cap seat
remove plug and
seal
insert the cap in the
hole respecting the
locator
cap locator
oce_000317_1300
1.300 Fi - FiN
1.230 Fi - FiN
view from above

15
examples of installation with twin pipe horizontal ducts
oce_010621_1400
oce_010716_0200
oce_010716_0300
The outlet pipe must never be any longer than 10 metres calculated with a
90° bend. For lengths greater than 6 metres, it is necessary, for the entire
length of the outlet duct, to use insulated pipes and bends so that the loss
of temperature along the duct is limited.
(*) The two end pieces (combustion air inlet - fl ue gas outlet) must be installed in the same area of the building.
(*)
oce_010621_1700
oce_010621_1800
examples of installation with twin pipe vertical ducts
IMPORTANT: The single duct for discharg-
ing fl ue gases must be suitably insulated where
it comes into contact with the walls of the
building, using appropriate insulation (such as
fi breglass padding).
For more detailed instructions on how to fi t
the accessories, please refer to the technical
notes provided with the accessories.
(L1+L2) max = 19 m (L1+L2) max = 18,5 m
(L1+L2) max = 9 m
L max = 5,5 m L max = 4,5 m
view from above

16
5.2. Pump connection
(FiN models only)
These models are sold without a circulation pump. If you want to oper-
ate the system pump directly from the boiler, the connection operations
are the following:
• Cut off power to the boiler with the two-pole switch.
• Open and remove the front door of the boiler and the cap.
• Pass the pump supply cable through the cable glands (use a har-
monized cable “HAR H05 VV-F” 3x0.75 mm2 with a maximum
diameter of 8 mm). Access the wiring board as described in the
paragraph: “Electrical connection Accessing the supply terminal
block.”
• Make the electrical connection following the diagram in the fi gure.
010706_0600
Figure 2a: pump connection
post circulation
3 min
post circulation
4h
oce.9402250715
▲
Fusibile
Fusible
Figure 2: Main terminal block
5. Electrical connection
Boilers are delivered with electrical connections and electrical power
supply cable.
Electrical safety of the appliance is guaranteed only by correct grounding,
in compliance with the applicable laws and regulations.
Connect the boiler to a 230 V mono-phase + ground power supply by
means of three-pin cable supplied with it and make sure you connect
polarities L (live) and N (neutral) correctly.
Use a double-pole switch with a contact separation of at least 3mm in
both poles.
In case you replace the power supply cable, fi t a “HAR H05-VV-F”3x0.75
mm2 cable with a diameter of 8 mm max.
5.1. Access to the power supply terminal block
• Isolate the electrical supply to the boiler by means of the double-pole
switch:
• Remove the cover pulling it up;
• Open the upper panel pulling on the upper corners of the boiler;
• Unscrew the two screws securing the control board to the boiler;
• Rotate the control board;
• Unscrew the screws securing the control board to the boiler;
• A 2A fast -blowing fuse is incorporated in the power supply terminal
block (fi g. 2).
(L) = LIVE WIRE brown
(N) = NEUTRAL WIRE blue
( ) = EARTH yellow-green
(1) (2) = Room thermostat contacts

17
0509_2603
6. Electrical diagram
KEY T.RISC = changing of the Central Heating maximum temperature GPL = type of gas connector A3/A11 = timer connector RISC. = Central Heating potentiometer POMPA = post-circulation time selection T-OFF = Central Heating stand-by time selection MAX.R = Central Heating output regulation
COLOUR OF THE WIRES C = Light Blue M = Brown N = Black R = Red G/V = Yellow/Green B = White
ROOM THERMOSTAT 230V
TANK’S NTC PROBE
POWER SUPPLY
FUSE
CENTRAL HEATING PUMP
WINTER-SUMMER-RESET SWITCH
GAS VALVE
IGNITION ELECTRODE
FLAME SENSING ELECTRODE
SAFETY THERMOSTAT
FLUE THERMOSTAT
CENTRAL HEATING TIMER JUMPER STORAGE TANK PUMP
TERMINAL BOARD M2
STORAGE TANK TIMER JUMPER
CENTRAL HEATING NTC PROBE
FAN
GAS PRESSURE SWITCH JUMPER

18
0312_1503
Figure 3: Electrical diagrams connection of multi-zones installation room thermostats and pumps and valves supply
Note: if the zone valves are not the double supply type, do not consider
the broken line connections. Zone relays are not necessary when using
valves with end-stroke micro-switch.
ROOM
THERMOSTAT
OF ZONE 1
ROOM
THERMOSTAT
OF ZONE 2
ROOM
THERMOSTAT
OF ZONE N
VALVE
OF QAA73 ZONE
BOILER
POWER SUPPLY
TERMINAL BOARD
0301_2003
QAA73
QAA73 TERMINAL BOARD
ROOM
THERMOSTAT
OF ZONE 1
ROOM
THERMOSTAT
OF ZONE 2
ROOM
THERMOSTAT
OF ZONE N
BOILER
POWER SUPPLY
TERMINAL BOARD
QAA73 TERMINAL
BOARD
PUMP
OF QAA73 ZONE
QAA73
7. Room thermostat
connection
• Reach the terminal board as described in paragraph 5.1.
• Take off the jumper from terminals (1) and (2) of the main terminal
board (see electrical diagram in paragraph 6).
• Insert the duplex cable through the cable clamp of the boiler and
connect it to the two terminals (use a “HAR H05-VV-F” 2x0.75 mm2
cable with a diameter of 8 mm max).
Multi- zones installation
In case of a multi-zones installation, the room thermostats have to be
connected following the diagram of fi gure 3.
Zone-valves or zone-pumps have to be electrically supplied separately
from the boiler as described in the electrical diagram of fi gure 3.
With QAA73 climatic regulator
The zone valve and zone pump controlled by the QAA73 have to be
electrically supplied following the diagram in fi gure 3.
Case 1: Installation without external probe
The heating fl ow temperature for the single zones must be set by means
of the Central Heating circuit temperature control device of the boiler
control panel (knob 2). In case of simultaneous demand from the main
zone, controlled by the QAA73, and one of the other zones, the heating
fl ow temperature will be the maximum value between the one processed
by the QAA73 and the one set on the boiler control panel (knob 2).
Case 2: Installation with external probe
The heating fl ow temperature for the single zones is the one processed by
the electronics (PCB) of the boiler according to the external temperature
and the set heating curve as described in the section “External probe
connection”.
In case of a simultaneous demand from the main zone, controlled by the
QAA73, and one of the other zones, the heating fl ow temperature will
be the maximum value between the one processed by the QAA73 and
the one processed by the boiler PCB.

19
8. Connecting a
programming timer
(accessory on demand)
Boilers are arranged for the connection of a programming timer (daily
or weekly), which diameter is 62 mm, to program the Central Heating
and the DHW operation.
To install the timer, see the following instructions:
Central Heating timer
• Reach the inside of the electrical box as described on paragraph 5.1:
“Access to the power supply terminal block”.
• Cut with a cutting nippers the box cover anchorage (pre-cut) on the
left side of the control panel.
• Install the timer, securing the screws.
• Remove the yellow jumper of the A3 connector on the boiler PCB
(contacts 2-4) and connect the “common and normally open” contacts
of the timer to the terminal board.
• Connect the motor contacts of timer to the A3 connector of the boiler
PCB (contacts 1-3).
If a battery-run timer is used, leave contacts (1-3) of A3 connector
free.
For the right connection of the timers see also the electrical diagram of
figure 4.
0506_2002
HEATING PROGRAMMER
Figure 4: Programmer clock connection
DHW TANK PROGRAMMER
TERMINAL BLOCK M2
BOARD
BOILER
Domestic Hot Water timer (WITH WATER STORAGE TANK)
• Remove the yellow jumper of the M2 terminal block on the boiler
(contacts 5-6) and connect the “common and normally open” contacts
of the timer to the terminal board.
Insert the connecting cable through a cable clamp of the boiler.
free.
For the right connection of the timers see also the electrical diagram of
figure 4.
For the SLIM UB 80 – 120 boiler unit do not take account of these
connections, follow the instructions provided with the appliance.
PCB

20
9. Domestic hot water tank
connection
The boilers are fitted to be connected to a boiler unit to generate domestic
hot water. The boiler unit may be supplied by BAXI or be acquired on
the market.
For the plumbing connection, follow the sketch shown in Figure 5.
0401_2103
Figure 5: Storage tank plumbing connection diagram
LEGEND
UB - TANK UNIT
UR - HEATING UNIT
PS - DOMESTIC HOT WATER PUMP
PR - HEATING PUMP
SB - TANK SENSOR
MR1 - HEATING DELIVERY ON MODELS WITH PLUMBING ACCESSORIES
MR2 - HEATING DELIVERY ON MODELS WITHOUT PLUMBING ACCESSORIES
MB - TANK COIL DELIVERY
RB - TANK COIL RETURN
For the electrical connection, depending on the case, follow the in-
structions given here.