Baxi LUNA HT 1.280 User manual

Wall-mounted condensing boilers
Installer’s and User’s Instructions
UNI EN ISO 9001
CERTIFICAZIONE DEI SISTEMI
QUALITA' DELLE AZIENDE
HT
BAXI S.p.A., one of the leading European enterprises to produce central heating and hot water devices for domestic use (wall-mounted gas-operated
boilers, floor-standing boilers and electrical water-heaters) has obtained the CSQ certificate of conformity to the UNI EN ISO 9001 norms. This
certificate guarantees that the Quality System applied at the BAXI S.p.A. factory in Bassano del Grappa, where your boiler was produced, meets
the standards of the UNI EN ISO 9001 norm, which is the strictest and concerns all organization stages and operating personnel involved in the
production and distribution processes.
0085

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.
Do not dispose of this booklet without reading it: you can find here some
very useful information, which will help you to run your boiler correctly
and efficiently
.
Do not leave any parts of the packaging (plastic bags, polystyrene, etc.) within childrenʼs reach as
they are a potential source of danger.
BAXI boilers bear the CE mark in compliance with the basic 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

Contents
1. Instructions prior to installation 4
2. Instructions prior to commissioning 4
3. Commissioning of the boiler 5
4. Filling the boiler 10
5. Turning off the boiler 10
6. Prolonged standstill of the system. Frost protection 11
7. Gas change 11
8. Servicing instructions 11
Instructions pertaining
to the user
9. General information 12
10. Instructions prior to installation 12
11. Boiler installation 13
12. Boiler size 13
13. Fittings present in the packaging 14
14. Installation of flue and air ducts 14
15. Connecting the mains supply 18
16. Gas change modalities 24
17. Setting the boiler parameters 27
18. Control and operation devices 28
19. Positioning of the ignition and flame sensing electrode 29
20. Check of combustion parameters 29
21. Activating the flue-sweeper function 29
22. Output / pump head performances 30
23. How to disassemble the DHW heat exchanger 30
24. Cleaning the cold water filter 31
25. Annual service 31
26. Boiler schematic 32-33
27. Illustrated wiring diagram 34-35
28. Technical data 36
Instructions pertaining
to the installer

4
Instructions pertaining to the user
2. Instructions prior to
commissioning
Initial lighting of the boiler must be carried out by a licensed technician. Ensure the following ope-
rations are carried out:
a) compliance of boiler parameters with (electricity, water, gas) supply systems settings.
b) compliance of installation with the laws and regulations in force.
c) appropriate connection to the power supply and grounding of the appliance.
The names of authorized Service Centres are listed on the accompanying sheet.
Failure to observe the above will render the guarantee null and void.
Prior to commissioning remove the protective plastic coating from the unit. Do not use any tools or
abrasive detergents as you may spoil the painted surfaces.
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 domestic hot water supply system
in compliance with its performances and output power.
Have the boiler installed by a Qualified Service Engineer and ensure the following operations are
accomplished:
a) careful checking that the boiler is fit for operation with the type of gas available. For more details
see the notice on the packaging and the label on the appliance itself.
b) careful checking that the flue terminal draft is appropriate; that the terminal is not obstructed and
that no other appliance exhaust gases are expelled through the same flue duct, unless the flue is
especially designed to collect the exhaust gas coming from more than one appliance, in conformity
with the laws and regulations in force.
c) careful checking that, in case the flue has been connected to pre-existing 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.
d) to ensure correct operation of the appliance and avoid invalidating the guarantee, observe the
following precautions:
1. Hot water circuit:
1.1. If the water hardness is greater than 20 °F (1 °F = 10 mg calcium carbonate per litre of water)
a polyphosphate or comparable treatment system responding to current regulations.
1.2. Domestic Hot Water circuit must be thoroughly flushed after the installation of the appliance
and before its use.
2. Heating circuit
2.1. new system
Before proceeding with installation of the boiler, the system must be cleaned and flushed
out thoroughly to eliminate residual thread-cutting swarf, solder and solvents if any, using
suitable proprietary products.
To avoid damaging metal, plastic and rubber parts, use only neutral cleaners, i.e. non-acid
and non alkaline. The recommended products for cleaning are:
SENTINEL X300 or X400 and FERNOX heating circuit restore. To use this product proceeding
strictly in accordance with the makerʼs directions.
2.2. existing system
Before proceeding with installation of the boiler, the system must be cleaned and flushed
out to remove sludge and contaminants, using suitable proprietary products as described in
section 2.1.
To avoid damaging metal, plastic and rubber parts, use only neutral cleaners, i.e. non-acid
and non-alkaline such as SENTINEL X100 and FERNOX heating circuit protective. To use
this product proceeding strictly in accordance with the makerʼs directions.
Remember that the presence of foreign matter in the heating system can adversely affect the
operation of the boiler (e.g. overheating and noisy operation of the heat exchanger).
Failure to observe the above will render the guarantee null and void.
1. Instructions prior to
installation

5
3-1. Description of keys
(2) This key can be pressed to set the central heating water output temperature as described
in point 3-3.
(3) This key can be pressed to set the domestic hot water temperature as described in point 3-4.
(10) Central heating mode operating key
The key can be pressed to activate four boiler central heating operating modes; these
modes are identified by a black cursor line underneath the relative symbol on the display,
and are as follows:
KEYS DISPLAY SYMBOLS
Central heating mode setting key
Data display reset key
Parameter setting key (increase value)
Parameter setting key (decrease value)
Program access and scroll key
Program access and scroll keys
Reset key
Domestic hot water temperature setting
key
Central heating water temperature setting
key
Domestic hot water on/off key
Resettable alarm warning
Flame present (on)
Outdoor temperature
Standby (off)
Operation in manual mode at minimum
temperature
Operation in manual mode at the maxi-
mum temperature set
Operation in automatic mode
Operation in central heating mode
Operation in domestic hot water mode
020503_1100
Figure 1
SECONDARY display
MAIN display
To correctly light the burner proceed as follows:
1) provide power supply to the boiler;
2) open the gas cock;
3) follow the directions given below regarding the adjustments to be made at the boiler control panel.
3. Commissioning of the
boiler

6
020503_0800
Figure 2
a) Automatic operation. Operation of the boiler is controlled by the timed program as described
in point 3-5.1 “Daily timed program for operation of the central heating system”;
b) Manual operation at the maximum temperature set. The boiler comes into operation
regardless of the timed program set. The operating temperature is that set using the key
(point 3-3: “Setting the maximum central heating temperature”);
c) Manual operation at minimum temperature. The operating temperature is that set in
point 3-6: “setting the minimum central heating temperature”.
d) standby. The boiler does not work in central heating mode, although the antifreeze function
is still enabled.
(1) Domestic hot water on/off key: This key can be pressed to activate or deactivate this
function, which is identified on the display by a black cursor line under the symbol .
(4) Reset key. In case of a fault, referred to in point 3-7 “Faults and resetting the boiler”,
the boiler can be restarted by pressing this key for at least two seconds.
If this key is pressed with no fault present, the display will show the message “E153”, and
the same key has to be pressed again (for at least two seconds) to restart the boiler.
(9) Data key. This key can be pressed repeatedly to display the following information:
- Temperature (°C) of the domestic hot water ( );
- outdoor temperature (°C) ( ); only provided with the outdoor temperature sensor probe
connected.
Press either of the keys to return to the main menu.
3-2. Setting the time
a) Press either of the keys to access the programming function;
the display will show the letter P followed by a number (program line);
020503_0700
Figure 3
Dash
“Automatic mode”
active
b) press the keys until the display shows P1, referring to the time to be set;
c) press the keys to set the time; on the display, the letter P will start to flash;
d) press the key to save and exit the programming function;

7
3-3. Setting the maximum central heating temperature
- Press the key (2-figure 1) to set the central heating water temperature;
- Press the keys to set the temperature required;
- press either of the keys (1 or 10 - figure 1) to save and return to the main menu.
N.b – With the outdoor sensor probe connected, the key (2 - figure 1) can be used to shift the
central heating curve. Press the keys to decrease or increase the room temperature in the
premises to be heated.
3-4. Setting the maximum domestic hot water temperature
- Press the key (3-figure 1) to set the maximum domestic hot water temperature;
- Press the keys to set the temperature required;
- press either of the keys (1 or 10 - figure 1) to save and return to the main menu.
3-5. Setting the daily program for operation in central heating and domestic hot water modes
3-5.1. Setting the daily times for central heating mode operation
- Press either of the keys to access the programming function;
a) press these keys until the display shows P11, referring to the program start time;
b) press the keys to set the time;
- press the key; the display will show P12, referring to the program end time;
- repeat the operations described in points a and b until the third and last cycle is reached
(program line P16);
- press the key to save and exit from the programming function.
3-5.2. Setting the daily times for domestic hot water mode operation
- Carry out the operations described in point 3-5.1 for program lines 31 to 36.
3-6. Setting the minimum central heating temperature
- press either of the keys to access the programming function;
- press these keys until the display shows P5, referring to the temperature to be set;
- press the keys to set the temperature required.
This operating mode is enabled when minimum temperature central heating mode is activated or
when the daily central heating program does not require heat.
N.b – With the outdoor sensor probe connected, parameter P5 can be used to set the minimum
room temperature in the premises to be heated.

8
3-8. Fault warnings and resetting the boiler
If a fault occurs, a flashing warning code appears on the display.
The fault warnings appear on the main display (figure 1 a) together with the symbol (Figure 4).
To reset, press the reset button for at least two seconds.
3-7. Table of user-settable parameters
020503_0500
Figure 4
Note: Parameters from P31 to P36 can be displayed only if the domestic hot water program has been
enabled as described in chapter 17 for the attention of the installer (parameter H91).
Range
0…23:59
25..80
00:00…24:00
00:00…24:00
00:00…24:00
00:00…24:00
00:00…24:00
00:00…24:00
00:00…24:00
00:00…24:00
00:00…24:00
00:00…24:00
00:00…24:00
00:00…24:00
0...1
Factory
setting
———-
25
6:00
22:00
0:00
0:00
0:00
0:00
0:00
24:00
0:00
0:00
0:00
0:00
0
Parameter description
Time of day setting
Minimum central heating temperature setting (°C)
Start of first daily period of automatic central heating
End of first daily period of automatic central heating
Start of second daily period of automatic central heating
End of second daily period of automatic central heating
Start of third daily period of automatic heating
End of third daily period of automatic central heating
Start of first daily period of domestic hot water production
End of first daily period of domestic hot water production
Start of second daily period of domestic hot water production
End of second daily period of domestic hot water production
Start of third daily period of domestic hot water production
Fine End of third daily period of domestic hot water production
Reset of daily central heating and domestic hot water production programs (factory
settings). Press the - + keys together for about 3 seconds; the number 1 appears on
the display. Confirm by pressing either of the keys
Parameter
N.
P1
P5
P11
P12
P13
P14
P15
P16
P31
P32
P33
P34
P35
P36
P45

9
0510_2701
Figure 4.1
Fault warnings appear on the secondary display (figure 1 b) alternating with the time, both of them
flashing (figure 4.1). It is not possible to reset malfunction warnings which appear on the secondary
display as the cause of the alarm has first to be removed.
All the faults are displayed in order of importance; if several faults occur simultaneously, the first to
be displayed is the one with highest priority. After the cause of the first fault has been removed, the
second one will be displayed, and so on.
If any given fault occurs frequently, contact the authorised Service Centre.
action required
call the authorised service centre.
call the authorised service centre.
call the authorised service centre.
press the reset key (for about 2 seconds: if this device is triggered
repeatedly, call the authorised service centre)
call the authorised service centre.
call the authorised service centre.
call the authorised service centre.
press the reset key (for about 2 seconds); if the fault persists, call the
authorised service centre)
switch off the electricity supply to the boiler for 10 seconds; if the fault
persists, call the authorised service centre)
press the key again (about 2 seconds)
Press and hold reset button (2 seconds approx.) then press again when
warning E153 appears
call the authorised service centre.
check that the system is at the rated pressure. (refer to the section on filling
the system). if the fault persists, call the authorised service centre.
Fault description
outdoor temperature probe sensor failure
ntc output sensor failure
domestic hot water ntc sensor failure
safety or flue gas thermostat tripped
loss of flame during operation (the ionization
current has fallen below the limit)
minimum fan speed limit is hurt
floor thermostat tripped
no gas
boiler circuit board error
the reset key has been pressed
inappropriately
internal error on boiler circuit module
fan speed threshold not reached
no hydraulic differential pressure
switch enabling signal
3-9. Fault warnings table
Fault
code
E10
E20
E50
E110
E128
E129
E132
E133
E151
E153
E154
E160
E164

10
To shut down the boiler switch off the electrical supply to the appliance.5. Turning off the boiler
The boiler is equipped with a hydraulic differential pressure switch that will inhibit the operation of
the boiler in the event of the pump seizing or running dry.
Important: Regularly check that the pressure displayed by the manometer (11 - Figure 20) is 1 to 1.5
bar, with boiler not operating. In case of overpressure, open the boiler drain valve.
In case the pressure is lower open the boiler filling tap (Figure 5a or 5b).
We recommend you open the tap very slowly in order to let off the air.
In case pressure drops occur frequently have the boiler checked by a Qualified Service Engineer.
4. Filling the boiler
020503_0400
Boiler filling tap Boiler drain valve
Figure 5a
LUNA HT 280 - HT 330
0010270500
Figure 5b
LUNA HT 1.120 - HT 1.240 - HT 1.280
Boiler filling tap

11
6. Prolonged standstill
of the system.
Frost protection
We recommend you avoid draining the whole system as water replacements engender purposeless
and harmful limestone deposits inside the boiler and on the heating elements.
In case the boiler is not operated during wintertime and is therefore exposed to danger of frost we
suggest you add some specific-purpose anti-freeze to the water contained in the system (e.g.: propy-
lene glycole coupled with corrosion and scaling inhibitors).
The electronic management of boilers includes a ʻfrost protectionʼ function in the central heating
system which operates the burner to reach a heating flow temperature of 30° C when the system
heating flow temperature drops below 5°C.
The frost protection function is enabled if:
* electrical supply to the boiler is on;
* the gas service cock is open;
* the system pressure is as required;
* the boiler is not blocked.
These boilers produced for natural gas can be converted to work with LPG.
Any gas change must be effected by a Qualified Service Engineer.
7. Gas change
To maintain efficient and safe operation of your boiler have it checked by a Qualified Service Engineer
at the end of every operating period.
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 (see section 5 “Turning off the boiler”).
8. Servicing instructions

12
Instructions pertaining to the installer
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 domestic hot water supply system
in compliance with its performances and output power.
Have the boiler installed by a Qualified Service Engineer and ensure the following operations are
accomplished:
a) careful checking that the boiler is fit for operation with the type of gas available. For more details
see the notice on the packaging and the label on the appliance itself.
b) careful checking that the flue terminal draft is appropriate; that the terminal is not obstructed and
that no other appliance exhaust gases are expelled through the same flue duct, unless the flue is
especially designed to collect the exhaust gas coming from more than one appliance, in conformity
with the laws and regulations in force.
c) careful checking that, in case the flue has been connected to pre-existing 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.
To ensure correct operation of the appliance and avoid invalidating the guarantee, observe the
following precautions:
1. Hot water circuit:
1.1. If the water hardness is greater than 20 °F (1 °F = 10 mg calcium carbonate per litre of water)
a polyphosphate or comparable treatment system responding to current regulations.
1.2. Domestic Hot Water circuit must be thoroughly flushed after the installation of the appliance
and before its use.
2. Heating circuit
2.1. new system
Before proceeding with installation of the boiler, the system must be cleaned and flushed
out thoroughly to eliminate residual thread-cutting swarf, solder and solvents if any, using
suitable proprietary products.
To avoid damaging metal, plastic and rubber parts, use only neutral cleaners, i.e. non-acid
and non alkaline. The recommended products for cleaning are:
SENTINEL X300 or X400 and FERNOX heating circuit restore. To use this product proceeding
strictly in accordance with the makerʼs directions.
2.2. existing system
Before proceeding with installation of the boiler, the system must be cleaned and flushed out
10. Instructions prior to
installation
The following remarks and instructions are addressed to Service Engineers to help them carry out a
faultless installation. Instructions regarding lighting and operation of the boiler are contained in the
ʻInstructions pertaining to the userʼ section.
Note that installation, maintenance and operation of the domestic gas appliances must be performed
exclusively by qualified personnel in compliance with current standards.
Please note the following:
* This boiler can be connected to any type of double- or single feeding pipe convector plates,
radiators, thermoconvectors. Design the system sections as usual though taking into account the
available output / pump head performances, as shown in section 22.
* Do not leave any packaging components (plastic bags, polystyrene, etc.) within childrenʼs reach
as they are a potential source of danger.
* Initial lighting of the boiler must be effected by a Qualified Service Engineer.
Failure to observe the above will render the guarantee null and void.
9. General information

13
Figure 7
020503_0300
12. Boiler size
Decide upon the boiler location, then tape the template on the wall.
Connect the pipework to the gas and water inlets prearranged on the template lower bar.
If you are either installing the boiler on a pre-existent system or substituting it, we suggest you also
fit settling tanks on the system return pipework and under the boiler to collect the deposits and scaling
which may remain and be circulated in the system after the purge.
When the boiler is fixed on the template connect the flue and air ducts (fittings supplied by the ma-
nufacturer) according to the instructions given in the following sections.
Connect the condensate outlet to the siphon supplied with the boiler. Connect the siphon to a drain,
making sure there is a continuous slope. Horizontal sections must be avoided.
11. Boiler installation
to remove sludge and contaminants, using suitable proprietary products as described in section
2.1.
To avoid damaging metal, plastic and rubber parts, use only neutral cleaners, i.e. non-acid
and non-alkaline such as SENTINEL X100 and FERNOX heating circuit protective. To use
this product proceeding strictly in accordance with the makerʼs directions.
Remember that the presence of foreign matter in the heating system can adversely affect the
operation of the boiler (e.g. overheating and noisy operation of the heat exchanger).
Failure to observe the above will render the guarantee null and void.
0505_2001
Figure 6
9912220300
BOILER WIDTH 450
BOILER CONNECTION POINTS
BOILER HEIGHT 780
0211_2203
LUNA HT 1.280 - HT 1.240 - HT 1.120 LUNA HT 330 - HT 280
MR: G3/4 heating flow
US: G1/2 domestic hot water outlet
GAS: G3/4 gas inlet to the boiler
ES: G1/2 cold water inlet
RR: G3/4 heating return
SC: condensation drain
MR: G3/4 heating flow
US: G3/4 domestic hot water boiler outlet
GAS: G3/4 gas inlet to the boiler
ES: G1/2 cold water inlet
RR: G3/4 heating return
SC: condensation drain

14
We guarantee ease and flexibility of installation for a gas-fired forced draft boiler thanks to the fittings
and fixtures supplied (described below).
The boiler is especially designed for connection to an exhaust flue / air ducting, with either coaxial,
vertical or horizontal terminal. By means of a splitting kit a two-pipe system may also be installed.
In case exhaust and intake flues not supplied by BAXI S.p.A. have been installed, these must be
certified for the type of use and must have a maximum pressure drop of 100 Pa.
Warnings for the following types of installation:
14. Installation of flue
and air ducts
010828_0200
C33 C33
C13 C13
C43 C53 C83
Figure 9
• template
• gas cock (16)
• inlet water tap with filter (17)
• heating system delivery cock (19)
• heating system return cock (18)
• washers
• telescopic tubes
• screws and wall plugs
13. Fittings present in
the packaging
Figure 8a
020503_0200
LUNA HT 280 - HT 330
18171619 Figure 8b
0010270500
LUNA HT 1.120 - HT 1.240 - HT 1.280
18171619
C13, C33 The terminals for the split flue must be provided
for within a square with 50 cm sides. Detailed
instructions are given together with each
accessory.
C53 The terminals for combustion air intake and
for the expulsion of combustion products must
not be provided for on opposite walls of the
building.
C63 The maximum pressure drop of the ducts must
not exceed 100 Pa. The ducts must be certified
for the specific use and for a temperature of over
100°C. The chimney flue must be certified in
accordance with the prEN 1856-1 Regulation.
C43, C83 The chimney or flue used must be suitable for
the use.

15
Flue
terminal
diameter
100 mm
133 mm
-
Each 45° bend
reduces the duct
max. length by
0,5 m
0,25 m
0,25 m
Each 90° bend
reduces the duct
max. length by
1 m
0,5 m
0,5 m
Max. length
of flue duct
10 m
15 m
80 m
Flue duct terminal
Coaxial Ø 60/100 mm
Vertical two-pipe
Horizontal two-pipe
Outer
terminal
diameter
100 mm
80 mm
80 mm
… coaxial flue - air duct (concentric)
990519_0400
Concentric outlet
Figure 10
Horizontal flue terminal Ø 60/100 mm installation options
LAS flue duct Ø 60/100 mm installation options
L max = 10 m
9912220900
L max = 10 m L max = 10 m
L max = 9 m
L max = 9 m
0002230400
This type of duct allows to disengage exhaust gases
and to draw combustion air both outside the building
and in case a LAS flue is fitted.
The 90° coaxial bend allows to connect the boiler to a
flue-air duct in any direction as it can rotate by 360°.
It can moreover be used as a supplementary bend and
be coupled with a coaxial duct or a 45° bend.
If the flue outlet is placed outside, the flue-air ducting
must protrude at least 18mm out of the wall to allow
alluminium weathering tile to be fitted and sealed to
avoid water leakages.
Ensure a minimum downward slope of 1 cm towards
the outside per each metre of duct length.
A 90° bend reduces the total duct length by 1 metre.
A 45° bend reduces the total duct length by 0.5 metre.

16
Vertical flue terminal Ø 60/100 mm installation options
This type of installation can be carried out both on a flat or pitched roof by fitting a terminal, an
appropriate weathering tile and sleeve, (supplementary fittings supplied on demand).
L max = 10 m L max = 10 m L max = 9 mL max = 8 m
9912221000
… separated flue-air ducting
This type of ducting allows to disengage exhaust flue gases both outside the building and into single
flue ducts.
Comburant air may be drawn in at a different site from where the flue terminal is located.
The splitting kit consists of a flue duct adaptor (100/80) and of an air duct adaptor.
For the air duct adaptor fit the screws and seals previously removed from the cap.
011015_0100
flue duct adaptor
Intake air duct adaptor
The 90° bend allows to connect the boiler to flue-air ducting regardless of direction as it can be ro-
tated by 360°. It can moreover be used as a supplementary bend to be coupled with the duct or with
a 45° bend.

17
A 90° bend reduces the total duct length by 0.5 metre.
A 45° bend reduces the total duct length by 0.25 metre.
020503_0100
Separated horizontal flue terminals installation options
IMPORTANT: Ensure a minimum downward slope of 1 cm toward the outside per each metre of
duct length
Make sure that the exhaust and intake ducts are securely fixed to the walls.
(L1 + L2) max = 80 m
L max = 15 m
0509_0606
010828_0600
The maximum length of the suction
duct must be 15 metres.

18
Separated vertical flue terminals installation options
Important: if fitting a single exhaust flue duct, ensure it is adequately insulated (e.g.: with glass wool)
wherever the duct passes through building walls.
For detailed instructions concerning the installation of fittings refer to the technical data accompanying
the fittings.
L max = 14 m
L max = 15 m
010828_0700
Electrical safety of the appliance is only guaranteed by correct grounding, in compliance with the
applicable laws and regulations.
Connect the boiler to a 230V monophase + ground power supply by means of the three-pin cable
supplied with it and make sure you connect polarities 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 fit a HAR H05 VV-Fʼ 3x0.75mm2 cable with an 8mm
diameter max.
The fuse, a fast-acting type rated 2A, is incorporated into the power supply terminals (remove the
black fuse holder to enable inspection and/or replacement).
15. Connecting the mains
supply
Figure 11
020523_0400
Terminals M1
Terminals M2 Cover
Cover

19
15-1. Description of the electrical connections to the boiler
Turn the control box downward to access terminal boards M1 and M2 used for the electrical connec-
tions by removing the two protective covers (see figure 11).
Terminals 1-2: connection of SIEMENS model QAA73 temperature regulator supplied as accessory.
Connection polarity is irrelevant.
The jumper fitted across the “TA” terminals 3-4 must be removed.
Read the instructions supplied with this accessory for correct installation and programming proce-
dures.
Terminals 3-4: “TA”, room temperature thermostat connection. Thermostats with integral accele-
rator resistor must not be used. Check that there is no voltage across the ends of the two thermostat
connection wires.
Terminals 5-6: “TP” floor temperature thermostat connection (commercially available device). Check
that there is no voltage across the ends of the two thermostat connection wires.
Terminals 7-8: connection of SIEMENS model QAC34 outdoor temperature probe supplied as
accessory..
Read the instructions supplied with this accessory for correct installation procedures.
Terminals 9-10: connection of domestic hot water precedence temperature sensor supplied as acces-
sory for connecting heating-only boilers to an external water heater.
Terminals a-b (230V): electricity supply for a zone valve / pump
See instructions in the “connecting a zone system” section.
15-2. Connecting the QAA73 temperature regulator.
The SIEMENS model QAA73 temperature regulator (optional accessory) must be connected to
terminals 1-2 of terminal board M2 in figure 11.
The jumper across terminals 3-4, provided for connection of a room temperature thermostat, must
be removed.
The settings of the domestic hot water temperature and domestic hot water production schedule must
be made using this device.
The timed program of the central heating circuit must be set on the QAA73 if there is a single zone,
or in relation to the zone controlled by the QAA73 device.
The timed program for the central heating circuit of the other zones can be set directly on the boiler
control panel.
See the instructions provided with the QAA73 temperature regulator for the user parameter pro-
gramming procedure.
IMPORTANT: For systems divided into zones, parameter 80 “HC2 gradient”, which can be set on
the QAA73 temperature regulator, must be set as _ _ . _ “not active”.
QAA73: parameters the installer can set (service)
By pressing the two PROG buttons together for at least three seconds it is possible to access the list
of parameters that the installer can display and/or set.
Press either of these buttons to change the parameter to display or change.
Press the [+] or [-] key to change the value displayed.
Press either of the PROG buttons again to save the change.
Press the information button (i) to quit programming.
Here follows a list of the most commonly used parameters:

20
- fault messages
In the event of fault, the display panel on the QAA73 shows the flashing symbol . Press the infor-
mation key ( ) to display the error code and a description of the fault (see table on paragraph 3.9).
Line no.
70
72
74
75
77
78
79
80
90
91
Default value
15
85
Light
On HC1
On
0
0
—.-
10 or 35
24 h/day
Range
2.5…40
25…85
Light, Heavy
on HC1
on HC2
on HC1+HC2
nil
On - off
0…360 min
0…360 min
2.5…40
—.- = not active
10 or 35…58
24 h/day
TSP HC-1h
TSP HC
TSP DHW
Parameter
HC1 gradient
Selection of central heating circuit temperature curve “kt”
HC1 max. output
Central heating system maximum output temperature
Type of building
Room compensation
Activation/deactivation of the influence of the room temperature.
If it is deactivated, the outdoor temperature sensor must be
installed.
Automatic adaptation of the temperature curve “kt” in relation
to the room temperature.
Opt Start Max
Maximum time the boiler is switched on ahead of the timed
program to optimise the temperature in the premises.
Opt Stop Max
Maximum time the boiler is switched off ahead of the timed
program to optimise the temperature in the premises.
HC2 gradient
Selection of temperature curve “kt” of the HC2 central heating
circuit of the low temperature zone if the SIEMENS AGU2.500
accessory is used.
DHW Red Setp
Minimum temperature of the domestic domestic hot water
DHW program
Selection of the type of timed program for domestic hot water.
24 h/day = always on
PROG HC-1h = as HC1 central heating program less
one hour
PROG HC = as central heating program
PROG ACS = specific domestic hot water program
(see also program lines 30-36)