Baxi PRIME HT 240 User manual

Wall-mounted condensing boilers
Installerʼs and Userʼs Instructions
BAXI S.p.A. is a leading European manufacturer of central heating and domestic hot water appliances (wall mounted gas
boilers, floor standing boilers, electric water heaters) and has been certified by CSQ as conforming to UNI EN ISO 9001.
This certification confirms that the Quality System of
BAXI S.p.A. in Bassano del Grappa, where this boiler was manufactured,
satisfies 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
PRIME HT
0085
GB

2
INSTRUCTIONS FOR THE USER
Dear Customer,
We are sure your new boiler will comply with all your require-
ments.
Purchasing one of the BAXI products satisfies your expecta-
tions: 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 children’s
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

3
INSTRUCTIONS FOR THE USER
9. General information 9
10. Instructions prior to installation 9
11. Boiler installation 10
12. Boiler size 10
13. Fittings present in the packaging 11
14. Installation of flue and air ducts 11
15. Connecting the mains supply 15
16. Changing gas type 22
17. Displaying electronic control card parameters on the boiler display (“INFO” mode) 25
18. Control and operation devices 27
19. Positioning of the ignition and flame sensing electrode 28
20. Check of combustion parameters 28
21. Activating the flue-sweeper function 29
22. Output / pump head performances 29
23. How to disassemble the DHW heat exchanger 30
24. Cleaning the cold water filter 30
25. Annual service 30
26. Using the Siemens QAA73 temperature regulator to program boiler parameters 31
27. Boiler schematic 33-34
28. Illustrated wiring diagram 35-36
29. Technical data 40
1. Instructions prior to installation 4
2. Instructions prior to commissioning 5
3. Commissioning of the boiler 5
4. Filling the boiler 7
5. Switching the boiler off 8
6. Prolonged standstill of the system. Frost protection 8
7. Gas change 8
8. Servicing instructions 8
CONTENTS
INSTRUCTIONS PERTAINING TO THE USER
INSTRUCTIONS PERTAINING TO THE INSTALLER

4
INSTRUCTIONS FOR THE USER
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:
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 accom-
plished:
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 de-
signed 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 maker’s 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 maker’s 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
INSTRUCTIONS FOR THE USER
0402_2501
The central heating system is disabled when the selector (1) is turned to Summer position ( ). All boiler safety systems
(the anti-freeze system and the pump and three way valve anti-blockage systems) and the domestic hot water system
remain active.
Important: When you first switch the boiler on, the burner may fail to light and the boiler may block until all the air is
expelled from the gas supply pipe.
If this happens, simply turn the selector (1) to ( ) for at least 1 second, then repeat the burner lighting process until pure
gas reaches the burner and it lights.
Legend:
1 Summer-Winter-Reset selector
2 Central heating function indicator
3 Domestic hot water (DHW) function indicator
4 Flame indicator
5 Display
6 Central heating temperature control knob
7 Domestic hot water temperature control knob
8 Pressure gauge
Figure 1
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.
Initial lighting of the boiler must be carried out by a licensed technician. Ensure the following operations 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.
2. INSTRUCTIONS PRIOR TO COMMISSIONING
3. COMMISSIONING OF THE BOILER

6
INSTRUCTIONS FOR THE USER
If a fault occurs, the display reads out an error message identifying it.
Note: If the error message contains more than 2 digits (e.g. E133), the display reads out the first two digits “E1” followed,
by the last two digits “33”, as shown in figure 3.
Figure 3 0402_2504
3.3 ERROR MESSAGES AND RESETTING THE BOILER
Figure 2
0403_2501
The boiler electronically modulates the burner flame according to the setting of the hot water temperature control knob
(7) and the water flow.
The system therefore guarantees that water temperature from the boiler remains constant even when only a small flow is
being drawn off.
To save energy, keep the domestic hot water temperature control knob turned to “--comfort--” (figure 2).
In the winter it will probably be necessary to increase the temperature of the hot water to suit conditions.
3.2 ADJUSTING DOMESTIC HOT WATER TEMPERATURE
The central heating system must be equipped with a thermostat to control room temperature.
If no room temperature thermostat is installed when the boiler is first started up, room temperature can be controlled using
the control knob (6).
Simply turn the control knob clockwise to increase room temperature or anti-clockwise to decrease it. The electronic
flame modulation system adapts the gas flow to the burner to suit varying heat exchange requirements as the boiler
achieves the set temperature.
3.1 ADJUSTING ROOM TEMPERATURE

7
INSTRUCTIONS FOR THE USER
Important: Regularly check that the pressure gauge (8 - figure 1) reads out a pressure of 1 - 1.5 bar when the central
heating system is cold. Open the boiler drain cock to reduce pressure if it is too high. Open the boiler filling cock (figure
4a or 4b) to increase pressure if it too low.
Always open the filling cock very slowly to allow any air to bleed off.
If the pressure in the system drops frequently, contact an authorised service centre to have the system checked.
4. FILLING THE SYSTEM
Corrective action
Call an authorised service centre.
Call an authorised service centre.
Call an authorised service centre.
Call an authorised service centre.
Turn selector (1) (figure 1) to “R” for at least 1 second. If this fault persi-
sts, call an authorised service centre.
Check that the pressure in the system is as specified. See the section on
filling the system. If this fault persists, call an authorised service centre.
Call an authorised service centre.
Turn selector (1) (figure 1) to “R” for at least 1 second. If this fault persi-
sts, call an authorised service centre.
Turn selector (1) (figure 1) to “R” for at least persists, call an authorised
service centre.
Turn selector (1) (figure 1) to “R” for at least 1 second. If this fault persi-
sts, call an authorised service centre.
Call an authorised service centre.Check the position of the ignition
electrodes (section 19).
Call an authorised service centre.
Description of fault
Outdoor temperature sensor fault
Central heating NTC sensor fault
Flue NTC sensor fault
Domestic hot water NTC sensor fault
Safety thermostat or fume sensor tripped
No signal from water pressure switch
Boiler max temperature exceeded (probable
pump jammed)
NTC flue sensor has cut out for overheat
It was cut off power supply without resetting the
gas boiler after the error code E125 or E130.
Gas supply fault
Boiler control card fault
Fan has not reached threshold speed
Error
code
E10
E20
E28
E50
E110
E119
E125
E130
E131
E133
E151
E160
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.
3.3.1 TABLE OF FAULTS AND ERROR MESSAGES

8
INSTRUCTIONS FOR THE USER
We recommend you avoid draining the whole system as water replacements engender purposeless and harmful limesto-
ne 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.: propylene glycole coupled with corrosion and
scaling inhibitors).
The electronic management of boilers includes a “frost protection” 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.
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).
6. PROLONGED STANDSTILL OF THE SYSTEM. FROST PROTECTION
7. GAS CHANGE
8. SERVICING INSTRUCTIONS
To switch the boiler off, simply turn the selector “1” to the “0” position. This switches off the electricity supply to the
appliance.
The boiler is equipped with a water pressure switch that prevents the boiler from starting up if there is no water in the
system.
5. SWITCHING THE BOILER OFF
Boiler filling cock Boiler drain cock
Figure 4a
PRIME HT 240 - HT 280 - HT 330 PRIME HT 1.120 - HT 1.240 - HT 1.280
0301_1008
Boiler filling cock
Figure 4b
0402_2505

9
INSTRUCTIONS FOR 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 maker’s 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 maker’s 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.
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 ‘Instructions pertaining to the user’ section.
Note that installation, maintenance and operation of the domestic gas appliances must be performed exclusively by qua-
lified 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, thermocon-
vectors. Design the system sections as usual though taking into account the available output / pump head performan-
ces, as shown in chapter 22.
* Do not leave any packaging components (plastic bags, polystyrene, etc.) within children’s reach as they are a potential
source of danger.
* Initial lighting of the boiler must be effected by a Qualified Service Engineer.
Note: Failure to observe the above will render the guarantee null and void.
9. GENERAL INFORMATION
10. INSTRUCTIONS PRIOR TO INSTALLATION

10
INSTRUCTIONS FOR THE INSTALLER
Figure 6
0402_2506
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 manufacturer) 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
12. BOILER SIZE
0505_2001
Figure 5
9912220300
BOILER WIDTH 450
BOILER CONNECTION POINTS
BOILER HEIGHT 780
0211_2203
PRIME HT 1.280 - HT 1.240 - HT 1.120 PRIME HT 330 - HT 280 - HT 240
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: condensate drain
MR: G3/4 heating flow
US: G3/4 domestic hot water boiler
delivery
GAS: G3/4 gas inlet to the boiler
ES: G1/2 cold water inlet
RR: G3/4 heating return
SC: condensate drain

11
INSTRUCTIONS FOR THE INSTALLER
010828_0200
C33 C33
C13 C13
C43 C53 C83
Figure 8
Figure 7a
0301_1007
18
17
16
19
PRIME HT 240 - HT 280 - HT 330
Figure 7b
0301_1008
18171619
PRIME HT 1.120 - HT 1.240 - HT 1.280
• template
• gas cock (16)
• inlet water tap with filter (17)
• heating system delivery cock (19)
• heating system return cock (18)
• seals
• telescopic joints
• 8 mm wall plugs and hooks
We guarantee ease and flexibility of installation for a gas-fired forced draft boiler thanks to the fittings and fixtures sup-
plied (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:
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 combu-
stion 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.
14. INSTALLATION OF FLUE AND AIR DUCTS
13. FITTINGS PRESENT IN THE PACKAGING

12
INSTRUCTIONS FOR THE INSTALLER
L max = 10 m
9912220900
L max = 10 m L max = 10 m
L max = 9 m
L max = 9 m
0002230400
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)
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 moreo-
ver be used as a supplementary bend and be coupled with a coaxial duct or a 45° bend.
990519_0400
Concentric outlet
Figure 9
LAS FLUE DUCT Ø 60/100 MM INSTALLATION OPTIONS
HORIZONTAL FLUE TERMINAL Ø 60/100 MM INSTALLATION OPTIONS
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 leaka-
ges.
Ensure a minimum downward slope of 1 cm towards the boi-
ler 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.

13
INSTRUCTIONS FOR THE INSTALLER
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 rotated by 360°. It can
moreover be used as a supplementary bend to be coupled with the duct or with a 45° bend.
Figure 10
VERTICAL FLUE TERMINAL Ø 60/100 MM INSTALLATION OPTIONS

14
INSTRUCTIONS FOR THE INSTALLER
0402_2507
Figure 11
A 90° bend reduces the total duct length by 0.5 metre.
A 45° bend reduces the total duct length by 0.25 metre.
IMPORTANT: Ensure a minimum downward slope of 1 cm toward the boiler 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
0207_0907
010828_0600
The maximum length of the suction
duct must be 15 metres.
SEPARATED HORIZONTAL FLUE TERMINALS INSTALLATION OPTIONS

15
INSTRUCTIONS FOR THE INSTALLER
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-F’ 3x0.75mm2 cable with an 8mm diameter max.
The fuse, a fast-acting type rated 2A, are incorporated into the power supply terminals (remove the black fuse holder to
enable inspection and/or replacement).
Figure 12
0409_0207
Terminals M1
Terminals M2
Cover
Cover
0409_0201
2
1
N
L
15. CONNECTING THE MAINS SUPPLY
SEPARATED VERTICAL FLUE TERMINALS INSTALLATION OPTIONS

16
INSTRUCTIONS FOR THE INSTALLER
Turn the control box downward to access terminal boards M1 and M2 used for the electrical connections by removing the
two protective covers (see figure 12).
Terminals 1-2, terminal board M1: room temperature thermostat “TA”.
Terminals 4-5, terminal board M2: connections for the optional SIEMENS QAA73 temperature regulator. These connec-
tions do not have any specific polarity.
Remove the bridge between terminals 1-2 “TA” on terminal board M1.
Read the instructions provided with the temperature regulator to ensure correct installation and programming.
Terminals 7-8: connections for the optional SIEMENS QAC34 outdoor temperature sensor. Read the instructions provi-
ded with the outdoor temperature sensor to ensure correct installation.
Terminals 9-10: connections for the optional domestic hot water priority sensor, for connecting single system boilers to
external DHW boilers.
An optional interface card is required to connect the QAA73 temperature regulator to boiler’s own electronic control card.
Connect the interface card to connector X 300 on the boiler’s electronic control card (figure 13).
Terminals 1-2-3, terminal board M2: connections for a zone control solenoid valve (see figure 15 in section 15.4).
Domestic hot water temperature and timing must be programmed on the QAA73 temperature regulator.
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.
See the instructions provided with the QAA73 temperature regulator for the user parameter programming procedure.
15.1 DESCRIPTION OF THE ELECTRICAL CONNECTIONS TO THE BOILER
15.2 CONNECTING THE QAA73 TEMPERATURE REGULATOR
0403_2502
Screw
Figure 13
Cable guide
LEGEND:
N.C. - Normally Closed contacts
C - Common
N.O. - Normally Open contacts
WIRE COLOURS:
M Brown
N Black
C Light blue
R Red
OPTIONAL INTERFACE
FOR QAA73

17
INSTRUCTIONS FOR THE INSTALLER
QAA73: parameters which can be set by the installer (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:
Line no.
70
72
74
75
77
78
79
90
91
Default value
15
80
Light
On HC1
On
0
0
10 or 35
24 h/day
Range
2.5…40
25…80
Light, Heavy
on HC1
on HC2
on HC1+HC2
nil
On - off
0…360 min
0…360 min
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 ti-
med program to optimise the temperature in the premises.
Opt Stop Max
Maximum time the boiler is switched off ahead of the ti-
med program to optimise the temperature in the premises.
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)

18
INSTRUCTIONS FOR THE INSTALLER
The SIEMENS model QAC34 outdoor temperature sensor probe (optional accessory) must be connected to terminals 5-6
of terminal board M2 in figure 13.
The procedures for setting the gradient of the temperature curve “kt” vary depending on the accessories connected to
the boiler.
0404_1604
Figure 14
a) Without the QAA73 temperature regulator
When an outdoor temperature sensor is connected, the central heating temperature control knob (fig. 14) shifts the hea-
ting curves (graph 2).
Turn the knob clockwise to increase room temperature, anti-clockwise to decrease it. Figure 14 shows the correct position
of the knob for operation without shifting the curves.
Modify parameter 532 on the QAA73 temperature regulator
to select the desired temperature curve “Kt”, as instructed
in the table of chapter 26.
Graph 1 shows the available temperature curves.
15.3 CONNECTING THE OUTDOOR TEMPERATURE SENSOR PROBE
- fault messages
In the event of fault, the display panel on the QAA73 shows the flashing symbol . Press the information key ( ) to display
the error code and a description of the fault.
Code Display Fault description
10 Outsidesense Outdoor temperature probe sensor fault (or parameter 75 disabled)
20 Boilersensor NTC delivery sensor fault
28 Flue gas NTC flue sensor fault
50 DHW sensor NTC domestic hot water sensor fault
60 QAA73 fault Ambient temperature probe fault
110 Boiler STL Safety thermostat tripped
119 W-pressSwi No signal from water pressure switch
125 - Pump blocked
130 FlueGasLimit NTC flue sensor has cut out for overheat
133 No flame Gas supply fault (No gas)
151 Burn lockout Boiler control card internal error
155 Reset off Maximum number of reset attempts (5) exceeded
160 Fan speed Fan speed threshold not reached

19
INSTRUCTIONS FOR THE INSTALLER
b) with QAA73 temperature regulator:
The temperature curve “kt” must be selected by setting parameter 70 “HC1 gradient” of the QAA73 temperature control
device as described in section 15.2 “QAA73: parameters which can be set by the installation engineer (service)”.
See graph 3 for selecting the curve referred to a room temperature of 20°C.
The curve is shifted automatically on the basis of the room temperature set using the QAA73 climate control.
If the central heating system is divided into more than one zone, the temperature curve must be set on the QAA73 and in
the boiler (See section 26 for boiler settings.). The appliance’s electronic control system provides a central heating output
temperature equal to the highest of the two values set on the QAA73 and in the boiler.
Graph 3
TM = Flow temperature
Te = Composite outside temperature
0403_2504
TM = Flow temperature
Te = Composite outside temperature
Graph 1
Graph 2
0409_1601
0410_0802

20
INSTRUCTIONS FOR THE INSTALLER
Figure 15
0402_25010
N Zone
(ROOM THER-
MOSTAT)
3 Zone
(ROOM THERMO-
STAT)
2 Zone
(ROOM THERMO-
STAT)
1 Zone
(QAA 73)
solenoid valve
1 Zone
Case 1: installation without an outdoor temperature sensor:
Use the central heating temperature control knob (6 - figure 1) on the boiler’s control panel to set central heating output
temperature to the various zones.
If heating requests are received simultaneously from the main zone controlled by the QAA73 and another zone, output
temperature will be the higher of the two values set on the QAA73 and on the boiler’s central heating temperature control
knob.
Case 2: installation with an outdoor sensor:
Central heating output temperature to the various zones is determined by the electronic control card on the basis of ou-
tdoor temperature and the preset heating curve as described in section 15.3.
If heating requests are received simultaneously from the main zone controlled by the QAA73 and another zone, output
temperature will be the higher of the values set on the QAA73 and calculated by the boiler’s electronic control card.
Use the boiler control panel to set room temperature in the other zones.
1 Zone
(ROOM THER-
MOSTAT)
The electrical connections and settings needed to control a multi-zone central heating system vary depending on what
accessories are connected to the boiler.
To permit the boiler to handle requests from individual zones, turn the Summer/Winter selector (1 - figure 1) on the boiler’s
front panel to Winter ( ) position.
a) Without a QAA73 temperature regulator:
Connect the switch for functioning in multi-zone mode in parallel to the “TA” terminals 1-2 on terminal board M1 as shown
in figure 12. Remove the default bridge.
Set the desired temperature with knob 6, figure 1, directly on the boiler control panel.
b) With the QAA73 temperature regulator:
Connect the switch controlling those zones not controlled by the QAA73 in parallel to the “TA” terminals 1-2 of terminal
board M1 as shown in figure 15. Remove the default bridge.
The zone controlled by the QAA73 is supplied by the zone 1 solenoid valve as shown in figure 15.
The QAA73 automatically controls room temperature in its own zone.
15.4 ELECTRICAL CONNECTIONS TO A MULTI-ZONE SYSTEM