Unical AIREX Series User manual

AIREX
INSTALLATION AND MAINTENANCE INSTRUCTIONS
150 - 200 - 200 UK

2
General Information
TABLE OF CONTENTS
1 GENERAL INFORMATION ................................................................................................................................................................................. 3
1.1 Symbols used in the manual......................................................................................................................................................................... 3
1.2 Appropriate use of appliance ........................................................................................................................................................................ 3
1.3 Water treatment ............................................................................................................................................................................................ 3
1.4 Information for system manager ................................................................................................................................................................... 3
1.5 Safety warnings ............................................................................................................................................................................................ 4
1.6 Technical data plate ...................................................................................................................................................................................... 4
1.7 General warnings.......................................................................................................................................................................................... 5
1.8 The Clean Air Act 1993 and Smoke Control Areas ...................................................................................................................................... 5
2 TECHNICAL FEATURES AND DIMENSIONS ...................................................................................................................................................6
2.1 Technical features......................................................................................................................................................................................... 6
2.2 Dimensions and hydraulic connections......................................................................................................................................................... 6
2.3 Main components ......................................................................................................................................................................................... 8
2.4 General Information ...................................................................................................................................................................................... 8
3 INSTALLATION INSTRUCTIONS ..................................................................................................................................................................... 11
3.1 General warnings ......................................................................................................................................................................................11
3.2 Installation standards.................................................................................................................................................................................12
3.3 Packaging.................................................................................................................................................................................................. 13
3.4 Transportation............................................................................................................................................................................................ 13
3.5 Assembly ..................................................................................................................................................................................................14
3.6 Connecting boiler to system ......................................................................................................................................................................14
3.7 Connecting to safety heat exchanger drain ............................................................................................................................................... 15
3.8 Recirculation pump.................................................................................................................................................................................... 15
3.9 Assembly instructions................................................................................................................................................................................ 16
3.10 Flue connection ......................................................................................................................................................................................... 21
3.11 Filling the system....................................................................................................................................................................................... 22
4 INDICATIVE HYDRAULIC AND ELECTRIC DIAGRAMS................................................................................................................................. 23
5 INSTALLATION / SUPPLY OF PANEL BOARD (code 41156) ......................................................................................................................... 32
6 STARTING THE BOILER .................................................................................................................................................................................. 41
6.1 Commissioning.......................................................................................................................................................................................... 41
6.2 Firewood.................................................................................................................................................................................................... 42
6.3 Wood moisture ..........................................................................................................................................................................................42
6.4 Dimensions................................................................................................................................................................................................ 42
6.5 Initial lighting checks..................................................................................................................................................................................42
6.6 Starting ...................................................................................................................................................................................................... 43
6.7 Combustion air adjustment........................................................................................................................................................................ 44
6.8 Checks to be carried out after commissioning........................................................................................................................................... 44
6.9 Warnings ................................................................................................................................................................................................... 45
6.10 Flow temperature adjustment.................................................................................................................................................................... 45
6.11 Summer mode........................................................................................................................................................................................... 45
6.12 Eliminating faults .......................................................................................................................................................................................46
7 INSPECTIONS AND MAINTENANCE .............................................................................................................................................................. 47

General Information
3
1.1 - SYMBOLS USED IN THE MANUAL
Pay special attention when reading this manual to the parts marked by the symbols:
NOTE!
Suggestions for the user
ATTENTION!
Possible hazardous situation
for the product and the environment
DANGER!
Serious danger for
personal safety and life
1.2 - APPROPRIATE USE OF APPLIANCE
The AIREX appliance has been built according to the current level of engineering and acknowledged tech-
nical safety rules.
Nonetheless, if improperly used, dangers could arise for the safety and the very life of the user and other
persons or damage to the equipment or other objects.
The appliance is intended to operate in hot air circulation heating systems.
Any other use must be considered improper.
UNICAL shall not be held liable for any damage resulting from improper use; in this case the user is fully
responsible for the risk.
Use according to the intended purposes also includes careful compliance with the instructions in this manual.
1.3 - WATER TREATMENT (see specific booklet)
• The hardness of the feed water conditions the frequency at which the domestic hot water exchanger must be
cleaned.
• If the water has a hardness greater than 15°f, we recommend using water softeners, chosen according to the
characteristics of the water.
• We recommend checking and cleaning the domestic hot water exchanger at the end of the first year of use and
every two years thereafter; on this occasion, also check the state of wear of the anode.
1.4 - INFORMATION FOR SYSTEM MANAGER
• The system manager must be instructed concerning the use and operation of his heating system, in particular:
• Give the system manager these instructions, as well as the other appliance documents inserted in the envelo-
pe inside the packaging. The system manager must keep this documentation for future consultation.
• Inform the system manager about the importance of the air vents and the flue gas exhaust system, pointing out
their essential features and the absolute prohibition of modifying them.
• Inform the system manager concerning control of the system’s water pressure as well as operations to restore it.
• Inform the system manager concerning correct control of temperatures, control units/thermostats and radiators
to save energy.
• Remember that the system must receive regular maintenance once a year and a combustion analysis must be
performed in the timetable foreseen by standards in force.
• Should the appliance be sold or transferred to a new owner or if you move and leave the appliance, always make
sure that the instruction booklet accompanies it in order to be consulted by the new owner and/or installer.
1GENERAL INFORMATION
Attention: this manual contains instructions for the exclusive use of the professionally qualified installer and/
or maintenance technician in compliance with current legislation.
The user is NOT qualified to intervene on the boiler.
The manufacturer will not be held liable in case of damage to persons, animals or objects resulting from failure
to comply with the instructions contained in the manuals supplied with the boiler.

4
General Information
1.5 - SAFETY WARNINGS
ATTENTION!
The appliance must be installed, adjusted and maintained by professionally qualified personnel, in
compliance with standards and provisions in force. Incorrect installation can cause damage to persons,
animals and objects for which the manufacturer cannot be held responsible.
DANGER!
NEVER attempt performing maintenance or repairs on the boiler on your own initiative.
Any work must be done by professionally qualified personnel.
We recommend stipulating a maintenance contract.
Insufficient or irregular maintenance can jeopardise the operating safety of the appliance and cause damage
to persons, animals and objects for which the manufacturer cannot be held responsible.
Modifying parts connected to appliance
Do not modify the following parts:
- the boiler
- the air, water and electricity lines
- the flue gas pipe, safety valve and heating water drain pipe
- construction parts which affect the operating safety of the appliance
Attention!
To tighten or loosen the screwed fittings, use only appropriate fixed spanners.
Incompliant use and/or inappropriate tools can cause damage (e.g. water leakage).
Explosive and easily flammable substances
Do not use or store explosive or easily flammable materials (e.g. petrol, paints, paper) in the room where the ap-
pliance is installed.
1.6 - TECHNICAL DATA PLATE
The technical data plate is adhesive and is included in the document case; it must be applied by the installer on the out-
side of the casing.
The serial number of the boiler is on the riveted plaque on the front plate of the body (front right top side).

General Information
5
1.7 - GENERAL WARNINGS
The instruction booklet is an integral and essential part of the
product and must be kept by the user or system manager.
Read the warnings contained in this instruction booklet carefully
as they provide important guidelines regarding installation, use
and maintenance safety.
Keep the booklet with care for further consultation.
Installation and maintenance must be performed in compliance
with standards in force according to the instructions of the
manufacturer and by qualified and certified personnel in
compliance with law.
By professionally qualified personnel we mean: personnel with
specific technical skill in the field of heating system components
for civil use, domestic hot water production and maintenance.
Personnel must have the qualifications foreseen by current
legislation.
Incorrect installation or improper maintenance can cause damage
to persons, animals or objects for which the manufacturer is not
responsible.
Before performing any cleaning or maintenance, disconnect the
appliance from the energy mains by acting on the switch of the
system and/or through the specific cut-off devices.
Not obstruct the terminals of the intake/exhaust ducts.
In case of failure and/or malfunctioning of the appliance, switch
it off and do not try to repair it or intervene on it directly.
Contact only personnel qualified in compliance with law.
Any repairs must be performed solely by personnel authorised by
Unical using original spare parts only. Failure to comply with the
above can jeopardise the safety of the appliance.
To guarantee appliance efficiency and its correct operation,
yearly maintenance must be performed by qualified personnel.
Should you decide not to use the appliance, parts entailing
potential sources of hazard must be made safe.
Should the appliance be sold or transferred to a new owner or
if you move and leave the appliance, always make sure that the
instruction booklet accompanies it in order to be consulted by
the new owner and/or installer.
Only original accessories must be used for all appliances with
optionals or kits (including electric).
This appliance is intended solely for the use for which it was
expressly designed. Any other use is to be considered improper
and therefore dangerous.
1.8 - THE CLEAN AIR ACT 1993 AND SMOKE
CONTROL AREAS
Under the Clean Air Act local authorities may declare the
whole or part of the district of the authority to be a smoke
control area. It is an offence to emit smoke from a chimney
of a building, from a furnace or from any fixed boiler if loca-
ted in a designated smoke control area. It is also an offence
to acquire an “unauthorised fuel” for use within a smoke
control area unless it is used in an “exempt” appliance
(“exempted” from the controls which generally apply in the
smoke control area).
In England appliances are exempted by publication on a
list by the Secretary of State in accordance with changes
made to sections 20 and 21 of the Clean Air Act 1993 by
section 15 of the Deregulation Act 2015. Similarly in Scotland
appliances are exempted by publication on a list by Scot-
tish Ministers under section 50 of the Regulatory Reform
(Scotland) Act 2014.
In Northern Ireland appliances are exempted by publication
on a list by the Department of Agriculture, Environment and
Rural Affairs under Section 16 of the Environmental Better
regulation Act (Northern Ireland) 2016.
In Wales appliances are exempted by regulations made by
Welsh Ministers.
Further information on the requirements of the Clean Air
Act can be found here:
https://www.gov.uk/smoke-control-area-rules
Your local authority is responsible for implementing the
Clean Air Act 1993 including designation and supervision
of smoke control areas and you can contact them for details
of Clean Air Act requirements.
The AIREX 150, 200 & 200 UK units have been recommen-
ded as suitable for use in smoke control areas when fitted
with a buffer tank as specified in Technical Features and
Dimensions section when burning wood logs as described
in the fuel section (see chapter 6.6 - Starting).

6
Technical features and dimensions
2.1 - TECHNICAL FEATURES
The heat generator mod. AIREX is a steel boiler running with
natural wooden logs, total gasification, flame inverted, with
the combustion chamber under negative pressure, suitable for
domestic heating.
It comes in the following models:
AIREX 150
AIREX 200
AIREX 200 UK
The AIREX boiler is complete with all the safety and control
devices required by relevant standards.
DESCRIPTION OF COMPONENTS:
• Steel boiler body with combustion chamber partially covered
with refractory material.
• Burner in refractory material.
• Vertical smoke ducts.
• Front door for loading wood covered with refractory material.
2TECHNICAL FEATURES
AND DIMENSIONS
1
116
E
1758
1808
730
800
1670
2
6
5
4
3
190
T4T4
T4T6
T2
T5
T5 T5
T6
T1T3T1 -T3
G
L
F H I
C
A
230
D
B310
7
88 8
65
2.2 - DIMENSIONS AND HYDRAULIC CONNECTIONS
fig. 1
1 Panel board
2 Wood storage door
3 Primary air setting
4 Secondary air setting
5 Flame sight glass
6 Combustion chamber door
7 Fan
8 Smoke pipes cleaning system control lever
T1 Central Heating flow
T2 Central Heating return
T3 Expansion vessel connection
T4 Chimney connection
T5 Safety heat exchanger connections
T6 Boiler drain
• Intermediate door complete with combustion air adjustments.
• Lower door covered with refractory material and equipped
with flame sight glass.
• Rear bottom door covered with refractory material for
extraordinary cleaning.
• Top smoke chamber with inspection door and ash removal
door.
• Flue gas evacuation with intake fan.
• Patented thermostatic valve system.
• Safety heat exchanger.
• Boiler body insulated with 80 mm thick mineral wool panels.
• Powder painted sheet steel casing.
• Recirculation pump kit (optional).
PANEL BOARD COMPONENTS:
• Main switch with light indicating presence of power.
• Safety thermostat for boiler overheating.
• General fuse.

Technical features and dimensions
7
- Efficiency and emissions compliant with
class 3 EN 303-5.
* Power achieved with good quality wood
containing 15% humidity.
** Pressure drops for flow rate correspon-
ding to a thermal drop of 15K.
*** Round logs approximately 10 cm in
diameter or square logs approximately
10x10 cm.
DN 65
DN 65
Rp 1½
300
R ¾
2461
151
1939
371
968
798
540
773
224
493
0,39
3
580
514x594
1626
120
MODELS
MAXIMUM NOMINAL OUTPUT* (kW)
MAXIMUM NOMINAL INPUT (kW)
DIMENSIONS
A
B
C
D
E
F
G
(mm)
(mm)
(mm)
(mm)
(mm)
(mm)
(mm)
CONNECTIONS T1
T2
T3
T4
T5
UNI 1092-1 PN16
UNI 1092-1 PN16
UNI ISO 7/1
(Ø mm)
UNI ISO 7/1
BOILER CAPACITY
WATER SIDE PRESSURE DROP**
MAX WORKING PRESSURE
WOOD STORAGE VOLUME
WOOD LOADING OPENING
LENGTH OF LOGS***
(m.w.c.)
(l)
(bar)
(l)
(mm)
(cm)
H (mm)
I (mm)
AIREX 150
149,3
166,8
2201
DN 65
DN 65
Rp 1½
300
R ¾
430
0,39
3
495
514x594
1475
100
151
1679
371
968
698
440
713
224
EMISSIONS
3
EFFICIENCY CLASS EN 303.5 3
3
EMISSIONS CLASS EN 303.5 3
690
CO at 10% O2(mg/Nm³) 687
43
DUST at 10% O2(mg/Nm³) 25
249
NOXat 10% O2(mg/Nm³) 232
R ¾
T6 UNI ISO 7/1 R ¾
2111L (mm) 1851
17
OGC at 10% O2(mg/Nm³) 15
230/250
Fan absorption (Volt/Watt) 230/250
AIREX 200
199,7
223,4
AIREX 200 UK
201
225
100 110 120 130 140 150 160 170 180 190 200
6000
6200
6400
6600
6800
7000
7200
7400
7600
7800
8000
8200
8400
8600
8800
9000
VOLUME OF BUFFER (LITRES)
CENTRAL HEATING DISSIPATION (kW)
AIREX 200 / 200 UK
AIREX 150
SIZING OF BUFFER
RECOMMENDED BUFFER SIZE (l) See diagram below
WEIGHT (kg)

8
Technical features and dimensions
2.3 - MAIN COMPONENTS
fig. 2
N.B.: The fire bars and the refractory steel grate are subject to wear; it is therefore
advisable to carry out an annual inspection to prevent faulty boiler operation.
2.4 - GENERAL INFORMATION
REVERSED FLAME
COMBUSTION
Everybody knows that to make a match last it must be held with
its head upwards. This is because it is necessary that the flame,
in its convective motion, does not meet another fuel in addition
to the one which has generated it. As in residential heating the
fuel is in the form of wood logs which are loaded from the top,
the flame has to go in the opposite way, i.e. downwards.
Natural draught is a source of depression which varies greatly
depending on the type of chimney, on weather conditions, on
the type of fuel, etc.
Therefore it is necessary to integrate it with forced ventilation in
order to stabilise it.
By fitting a fan it is possible to considerably reduce the section
of the gas passages on the grate and furthermore there are no
problems with cold starts.
The small grate permits a more controlled passage of combustion
air, contrarily to what happens with large traditional grates.
The air can be perfectly dosed because the grate, covered with
burning wood, has the same crossing resistance and thus the
combustion will be always optimal.
1. Panel board
2. Top panel
3. Anti-smoke door fitted on hinges
4. Wood storage door with refractory material,
gasket and handle
5. Primary and secondary air adjustment units
6. Combustion chamber door with gasket,
refractory material and flame sight glass
7. Combustion chamber in thick steel
8. Catalyst in refractory material
9. Burner in refractory material with thermal steel grate
10. Steel boiler body
11. Bypass
12. Rear door for extraordinary cleaning
13. Smoke chamber inspection door
14. Smoke chamber
15. Safety heat exchanger
16. Flue gas intake fan
17. Smoke pipes cleaning system
18.Thermostatic valve system
19. Boiler body insulation in mineral wool
M C.H. flow
R C.H. return
VE Expansion vessel connection
Unical has already used this principal for many years with the
GASOGEN boiler.
The AIREX boiler today has reached such a high level of
perfection that it can pass all the most stringent tests foreseen
by the European Standards in force concerning the environment.
2 1
3
4
6
5
7
9
10
11
16
14
12
15
13
R
M
VE
18
19 17
8

Technical features and dimensions
9
fig. 3
AIREX BOILER STRUCTURE
The hydraulic system inside the boiler is designed in such a
way that a thermostatic system always keeps the temperature
of the water surrounding the wood storage high so as to eliminate
the dangerous phenomenon of condensation. The boiler body
is composed of two elements placed inside the other, so that
between the two a cavity of water (fig.3) is formed.
The large capacity wood storage has a special thermal and
mechanical high resistance refractory press.
The lower catalyst in refractory material perfects combustion
by burning unburnt materials and thus reducing the values of
pollutant particles.
The following parts can be distinguished (fig.3):
1. Wood storage and drying zone
2. Gasification zone
3. Embers zone
4. Burner in refractory material
5. Combustion chamber
6. Heat exchange surface
7. Catalyst in refractory material
8. Boiler water
9. Thermostatic system
10. Bypass
11. Safety heat exchanger
12. Primary air inlet channels
M System hot water flow
R System return
GASIFICATION ZONE (2)
Gasification takes place in the lower part of the firewood storage.
It is very important that gasification is as regular as possible, so
as not to overload the burner with gas.
Gasification speed depends on the amount of wood and the
dimensions of the drying zone. Generally, it is better to use lar-
ge logs if they are dry and small logs if the wood is moist. The
quantity of primary air, proportional to the delivered output, is
regulated via the adjustment system.
EXCHANGE SURFACE (6)
The wood contains low levels of sulphur allowing the boiler to
run with flue gas at relatively low temperatures.To improve boiler
efficiency, we have therefore designed an exchange surface with
smoke pipes (fig. 4).
A manually “scraping” system allows to keep the inner exchange
surfaces of the pipes clean; this operation, which lasts a few
seconds, is recommended whenever wood is loaded.
The solid combustion residues (ashes), which lie on the high
temperature refractory catalyst (fig. 3, pos. 7), will become, with
time, always lighter until they will be carried by the gas speed
and deposited in the lowest area of the smoke chamber, from
which they will be removed during cleaning.
fig. 4
M
R
9
10
11
4
1
6
2
12
3
5
7
8
F
F
F

10
Technical features and dimensions
fig. 5
1. Refractory steel grate
2. Refractory cast-iron fire bars
REFRACTORY BURNER (4)
The burner is made up of refractory stone (fig. 3, pos. 4).
This stone has a rectangular central opening through which the
flame passes.
The embers lie directly on the stone which divides the fire wood
storage from the lower combustion chamber.
Furthermore the main refractory stone has a rectangular seat in
which the opportunely grooved cast iron fire bars are placed (fig.
5, pos. 2), which receive the secondary air from a front distributor.
The embers are prevented from falling by a refractory steel grate.
The combustion gases, poor in oxygen and still rich in carbon
not yet combined, travel across the embers and enter the opening
in the centre of the main stone.
Inside this pre-combustion chamber, the gases combine with
the pre-heated secondary air coming through the grooves of
the two cast iron fire bars.
The flame comes out from the lower opening and invades the
combustion chamber.
Due to the high temperatures the refractory burner will become
a bright red colour.
COMBUSTION CHAMBER (5)
Combustion is optimised by increasing the flame temperature
and producing a strong turbulence in the bottom chamber.
For this reason the flame, in addition to not touching cold walls
irrigated by water, bounces and is divided on a semicircular
cradle which rests on the lower exchange surfaces, which, aside
from delimiting the smoke passages, also has the task of
collecting the ashes and possible embers.
The flames, after having bounced off the walls of the bottom
area and the refractory ones, direct themselves with a whirling
motion towards the front part of the combustion chamber and
enter the flue ducts. Combustion will be complete and clean and
the dominant colour will be that of the ashes: white.
M = Hot water flow
R = System return
VE = Expansion vessel
P = Primary air
S = Secondary air
F = Flue gas
fig. 6
THERMOSTATIC VALVES (9)
As is well known, wood normally has a high moisture content
when compared with other types of fuels. The first operation
which occurs inside the fire wood storage is therefore the drying
phase.
The high moisture content can then cause considerable
condensation in the boiler and also in the chimney.
To limit the problem in the boiler it is necessary to maintain high
working temperatures.
For this reason the boiler is equipped with a patented
thermostatic system (fig. 7) which permits the boiler temperature
to be kept constantly high, in particular in the fire wood storage,
where condensation is more likely to occur.
In order to reduce the consequences of condensate formation
(tar dripping, corrosion, etc.) it is advantageous to dimension,
time by time, the wood load to the actual needs, so as to prevent
long stop overs with the wood storage completely full of humid
wood.
Nevertheless all these expedients do not impede the formation
of condensate in the chimney. Therefore we suggest, when bu-
ilding the chimney, to use air-tight components, to prevent the
condensate from damaging the building structure.
fig. 7
1
2
F
F
PP
S
P
P
P
S
S
F F F
F
F
R
M
VE
T1
1
2
3

Installation instructions
11
3INSTALLATION
INSTRUCTIONS
3.1 - GENERAL WARNINGS
ATTENTION!
This boiler is intended solely for the use for
which it was expressly designed.
Any other use is to be considered improper
and therefore dangerous.
This boiler heats water at a temperature
lower than the atmospheric pressure boiling
temperature.
ATTENTION!
The appliances are designed to be installed
inside suitable rooms or technical spaces
only. The appliances cannot be installed or
operate outdoors. Outdoor installation can
cause malfunctioning and be dangerous.
Choose specifically designed appliances for
outdoor installation.
Before connecting the boiler, have professionally
qualified personnel:
a) Thoroughly wash all the piping of the system
to remove any residue or impurities which
could jeopardise proper operation of the boi-
ler.
b) Check that the chimney/flue has an appropriate
draught, without any bottlenecks, and that no
exhausts from other appliances are inserted,
unless the flue has been implemented to
accommodate several utilities according to
specific standards and prescriptions in force.
Only after this check can the fitting between
the boiler and chimney/flue be mounted.
ATTENTION!
The appliance must be installed by a qualified
technician with the technical-professional
requirements according to law, which
under his own responsibility, guarantees
compliance with standards according to
good practice rules.
The boiler must be connected to a central heating
system and/or domestic hot water production
network compatible with its efficiency and output.

12
Installation instructions
3.2 - INSTALLATION STANDARDS
AIREX it is a boiler designed to run with firewood.
This appliance must be installed according to that indicated
by standards in force in the country where the boiler is
installed.

Installation instructions
13
3.3 - PACKAGING
The AIREX boiler is delivered disassembled: the casing, fan,
panel board, handles and accessories for cleaning are delivered
in separate boxes (fig. 8).
After having unpacked
everything, make sure
that the supply is complete
and undamaged.
If in doubt, do not
use the appliance
and contact the supplier.
Keep the packaging material
(cardboard boxes, straps,
plastic bags, etc.)
out of the reach of children
as they are potential sources
of danger.
Unical will not be held liable
for damage to persons, animals or
objects due to failure to comply
with the instruction above.
Description of packs:
1. Boiler body
2. Package containing casing and boiler insulation
3. Package containing casing and boiler insulation
4. Package containing the panel board
5. Package containing: air inlet manifold, handles, flame control mirror, screws
and nuts, cleaning accessories.
6. Package containing flue gas intake fan
The document envelope, inserted in the wood storage,
contains:
- System manager operating instructions
- Installation and maintenance instruction booklet
- Warranty
- Technical data plate
If the boiler is stored for long periods, it should be adequately
protected.
fig. 8
3.4 - TRANSPORTATION
To facilitate the transport, loading and unloading of
the boiler, there are suitable hooks “G” (fig. 8) for
lifting on the upper part of the boiler body.
4
23
1
G
56

14
Installation instructions
800
1000
1500 600
600
3.5 - ASSEMBLY
The AIREX boiler does not differ from a normal solid fuel fired boi-
ler; therefore there are no particular installation codes of practice
other than the safety provisions foreseen by standards in force.
The installation room must be properly ventilated by
openings with a total surface of at least 0.5 m².
To make it easier to clean the smoke circuit,
in front of the boiler, there must be a
free space no less than the
length of the boiler.
Check at least that the doors can open 90°
without meeting any obstacles.
The boiler can be placed directly on the floor,
as it is equipped with a self-supporting frame.
Nevertheless, in case of installation in very
damp boiler rooms, it is preferable to provide
cement support.
When installation has been performed, the
boiler must be in a horizontal position and
stable so as to reduce possible vibrations
and noise.
An adequate clearance space must be left behind the
boiler to allow the fan to be opened and serviced.
POSITIONING IN
BOILER ROOM
N.B.: The minimum clearances indicated to the side are
required to allow the AIREX boiler correct maintenance.
fig. 9
3.6 - CONNECTING BOILER
TO SYSTEM
Attention!
Make sure that there are no mechanical
stresses while connecting the pipes to avoid
the risk of leakage!
Heating flow and return pipes must be connected
to the boiler at the respective fittings as indicated on page 7.
For the dimensioning of the heating circuit pipes, you must take
into account pressure drops caused by radiators,
thermostatic valves, radiator stopping valves and by the
configuration of the system.
The laying of the pipes must be designed taking every neces-
sary precaution to avoid air pockets and to facilitate continuous
degassing of the system.
Make sure that the pipes of the water and heating
system are not used as earthing electrodes of
the electric or telephone system.
They are absolutely not suitable for this type of
use. Serious damage could result for the piping,
boiler and radiators in a short amount of time.

Installation instructions
15
SCARICO
1
2
ALIMENTAZIONE
3.7 - CONNECTING TO SAFETY HEAT
EXCHANGE DRAIN
Solid fuel fired boilers must be installed with
the safety devices foreseen by relevant laws
in force.
For this purpose, AIREX boilers are fitted with
a safety heat exchanger.
The installer must fit a heat discharge valve on this safety heat
exchanger, with the control bulb inserted in the bulb holder placed
on the rear wall of the AIREX boiler.
We recommend fitting the valve on the cold water inlet.
Provide a drain pipe with a funnel and a siphon leading to an
appropriate drainage at the heat exchanger outlet.
This drainage must be controlled on sight.
Attention!
If this precaution is not taken, triggering of
the thermal discharge valve can cause
damage to persons, animals and objects for
which the manufacturer cannot be held
responsible.
3.8 - RECIRCULATION PUMP
For correct boiler operation, a recirculation pump must be
installed.
The recirculation pump, supplied in an optional kit, must be
connected is indicated in fig. 19.
If it is not installed, besides limiting the boiler’s lifespan, it
will invalidate the warranty.
ATTENTION!
The hardness of the mains water supply con-
ditions the boiler’s lifespan.
Depending on the hardness of the mains water
supply, the possibility of installing appropriate
water softeners for domestic use has to be taken into con-
sideration in compliance with DM n° 443 of 21/12/90.
It is always recommended to treat water with a hardness
greater than 15°f .
fig. 10
FEED
DRAIN

16
Installation instructions
3.9 - ASSEMBLY
INSTRUCTIONS
Fan assembly
Fit the fan to the smoke chamber.
fig. 11
fig. 12
IMPORTANT!
Before installing the fan, check the perfect
tightness of the bypass cover which links the
wood storage directly with the smoke chamber.
To do this, with the wood loading door open, act
manually on the control rod of the bypass simulating closing of
the door and make sure there is no gap.
If so, adjust the length of the rod.
Mount the bottom closing cover of smoke chamber with the
relative seal.
Wood must be loaded in as little time as possible to keep the
impeller of the fan from overheating and thus malfunctioning.
This problem occurs more quickly the more the wood loading
door is opened.
Assembling the handles
- Mount the screw and nut on the top door and screw the knob
(pos. 1, 2, 3).
Fit the knob (pos. 4) on the top door closing handle.
- Mount the screw and nut on the bottom door and screw the
knob (pos. 1, 2, 3).
- Install the air manifolds (pos. 5).
Adjustment of the primary and secondary air draughts
is described on page 43.
- Attach the flame control mirror (pos. 6) to the
sight glass on the bottom door.
4
1
1
2
2
3
3
6
5

Installation instructions
17
fig. 14
1
2
3
4
- Wrap on the mineral wool insulation the plastic strap and
insert one of its ends in the locking slot as shown in the
detail 1.
- Holding the end of the strap already inserted, proceed
with the other end by folding the plastic pin inward as
shown in detail 2.
- Pull the two ends of the strap (as shown in details 3 and
4) until the strap adheres to all the mineral wool covering
the boiler body.
It is recommended not to overstretch the strap; an
excessive crushing of mineral wool would cause a
non-homogeneous insulation.
In case of maintenance it is possible to remove the strap
by acting on the locking slots.
Fitting body insulation
- Fit the front insulation of the body making a suitable cut
near the upper flow connection and upper expansion vessel
connection.
Fit the insulation with straps is described in fig. 14.
- Fit the rear insulation of the body making a suitable cut near
the lower return pipe connection.
Once the insulation has been mounted, it must be able to be
lifted at the top to allow the smoke pipe cleaning system to
be accessed and serviced and then repositioned.
fig. 13
Fig. 14
TAGLIARE
CUT

18
Installation instructions
Assembling turbulator control lever
mechanism and microswitch
- Fit the extension of the turbulator cleaning lever mechanism
(pos. 1).
- Fit the microswitch (pos. 2) to the bracket making sure it
makes correct contact with the plate at the upper wood loading
door opening; adjust it if necessary.
Remember that the contact of the microswitch
must be normally open with the wood
loading door closed.
- The turbulator control lever and the knob
(pos. 3 and 4) must be fastened after the right
rear side casing has been assembled.
fig. 15
2
1
3
4
Assembling casing
- Fit the rear side panel support crosspiece (pos. 1) to the smoke
chamber.
- Position the side panels (pos. 3, 4, 5, and 6) on the boiler
body.
The panel with the hole is the one on the rear right.
- Fit the panel board (pos. 8) onto the front casing cover (pos.
7) with the finned nuts.
- Remove the cover of the electric control board, fix the board
on the upper panel (pos. 7) and pass the outgoing electric
cable of the fan and the thermostat capillaries (unrolling them
carefully) and the incoming electric cable of the door opening
microswitch, of the power line and of the pumps through the
middle hole of the panel.
Keep the electric cables from coming into contact with
the smoke chamber and/or parts of it or from being cut
by friction.
A silicon gasket to be fitted on the top part of the rear
plate of the boiler has been supplied in the accessory
box for this purpose.
- Place the casing cover (complete with panel board) on the
sides of the casing already mounted.
- Mount the two top rear panels (pos. 11 and 12).
- Place the bulb of the safety thermostat in the rear right bulb
holder (small conduit) fastening it with the fixing clip.
- Place the bulb of the flow probe (S4) in the rear left bulb holder
(large conduit) fastening the cable with the fixing clip.
- Insert the bulb of the return probe (S5) in the bulb holder on
the boiler return pipe (between the boiler and the recirculation
pump).
- Fit the bulb holder lg. 100 (supplied in the accessory bag) on
the specific attachment on the flue gas outlet pipe and insert
the flue gas probe inside.
Direct the thermocouple connection cable towards the panel
board and connected it as indicated on the wiring diagrams
associated to the hydraulic diagrams described on page 23;
pay the utmost attention that the metal sleeve (for the section
inside the panel board) does not come into contact with live
parts of the board.
For connection of the probes S1, S2, and S3, comply with that
indicated in the electric-hydraulic principle diagrams according
to the type of plant indicated on page 23.
- Fit the bottom back panel (pos. 13) to the casing.
- Fit the top back panel (pos. 14) to the casing.
Mount the cable clamps (pos. 15) on the back panel.
The electric wires coming out of the back of the boiler will be
connected with the specific cable gland terminals fixed on the
back panel, tightening them moderately.
- Perform the electrical connections as indicated in the wiring
diagrams described on page 23.
- Put the cover back on the electric control board.
- Fit the upper rear cover (pos. 16).
- Fit the turbulator control lever and the knob (pos. 17 and 18)
(pos. 3 and 4, fig. 15).
- Apply the boiler TECHNICAL DATA plate on the right side
of the casing after having cleaned the concerned area and
removed any grease with a suitable solvent.
Remove the protective film from the plate and apply it making
sure it sticks perfectly using a plastic spatula.
Do not remove the plate as it would no longer stick.

Installation instructions
19
8
11
1
42
7
3
10
17
6
5
18
12
fig. 16
fig. 17
13
14
15
16

20
Installation instructions
4
6
8
5
6
7
3
5
2
1
2
S ONDA DI R ITOR NO
9
10
1
11
fig. 18
Solid fuel fired boilers must be installed with the safety
devices foreseen by relevant laws in force.
For this purpose, AIREX boilers are fitted with a safety heat
exchanger.
See also chap. 3.7.
Connect the thermal discharge valve (pos. 1) and insert the
probe in the relative bulb holder (pos. 2).
The thermal discharge valve may be mounted either on the right
or on the left as long as the probe can be inserted in the specific
bulb holder.
It is recommended to convey the discharge.
Remember that for solid fuel boilers, due to the thermal inertia
of the fuel, the installation of the thermal discharge valve is
mandatory.
SCARICO
1
2
ALIMENTAZIONE
fig. 19
Recirculation kit
For the correct operation of the AIREX range of boi-
lers, it is necessary to foresee a recirculation pump,
to prevent a low temperature return, which could
compromise the life of the boiler.
UNICAL, to help its customers, has therefore
developed a hydraulic kit for recirculation that
enhances the function of the circulating water in the
boiler.
This kit is supplied as an option and is available by
indicating the model of your boiler.
FEED
DRAIN
RETURN PROBE