Flexiheat FHSPN 35 User manual

1. General information
The Original Instruction Manual constitutes an
integral and material part of the product, and is to be
transferred to the user with the transfer of
ownership. It needs to be studied thoroughly and
retained for future reference, as all remarks included
in it provide important hints on safety during
installation, use and maintenance of the appliance.
The heating unit needs to be assembled and
installed with adherence to the standards in force in
the country of operation, according to indications of
the manufacturer, and operated by trained
professionals. Improper device installation might be
the cause of injury to people and animals and of
material damage, for which the manufacturer is not
liable.
The air heating unit may be used exclusively for the
purpose for which it was clearly designed. Any other
use shall be considered improper, and,
consequentially, hazardous.
In case of errors during installation, use or
maintenance that were caused by negligence in
terms of the law in force, of provisions in force or the
Original Instruction Manual (or any different manual
supplied by the manufacturer), the manufacturer is
not liable for any contract or other responsibility for
the arising damages, and the equipment warranty
becomes void.
The choice of heating units for heating buildings is
conducted based on a building thermal heat balance
sheet, with particular consideration of losses
stemming from the transfer of heat to buildings.
2. Foreseen use of the heating unit
The NPS series heating units are foreseen for
heating air in small to medium-sized rooms, in
buildings without a water-based central heating
system.
Thermal heat is generated as a result of combustion,
and the thermal energy is transferred through the
combustion chamber walls and the heat exchanger.
The air heaters are devices ideally suited for:
industrial halls, workshops
warehouses, shops, megastores,
additional burner - pellets) directly from the heat
exchanger tube to the outside environment,
without any intermediate liquid. During
combustion, smoke and other gases are
generated, which are ventilated by the chimney
line.
NOTE!
Due to the specifics of operation of the solid
fuel-fired air heater, operation supervision in
the form of operation parameter control is
necessary.
combustion chamber with thermal heat
exchanger (body)
covers
ash tray
cast iron grid
ventilator system
electric switch box with thermostat
air blower.
Thermal heat is generated as a result of combustion
in the combustion chamber, which is equipped with a
cast iron grid. The thermal energy is transferred from
the combustion gases to the ambient fresh air by
means of natural and forced convection.
The air and combustion gases are passed through
different ducts, which are welded and properly
insulated. The emerging combustion gases, after
cooling, are led out through a duct that must be
connected to a chimney or gas duct. The chimney or
gas duct diameter must be sufficiently large to
guarantee effective combustion gas removal. The air
used in the combustion process is taken directly
from the room or building being heated. For this
reason, it is of paramount importance to provide
appropriate ventilation for the heated room or
building that will guarantee the provision of an
appropriate volume of fresh air. The ash emerging in
the combustion process falls to the ash tray, from
which it can be removed without difficulty. The
heated air is distributed around the room through a
rotating blower, which is mounted in the top area of
the air heater.
The electric switch box with thermostat is
responsible for the assurance of electric energy to
the heater fan. When the heater outer casing
reaches the set temperature (35 °C), the fan is
switched on and warm air is distributed around the
room, in which the heater was installed.
3. Heater description
The FHSPN series air heaters are composed
of the following parts:
wholesalers
swimming pools, tennis courts, sports halls
exhibition tents, trade fair stands
religious sites.
The FHSPN series heater is a device generating
thermal heat through combustion of solid fuel
(wood, coal, following the installation of an

The ventilator is automatically shut down if the
heater casing cools down to less than 35 °C.
4. Fuel parameters
HINT!
The wood should be seasoned for at least a
year. Wood humidity exceeding 25% can
cause energy losses and damage to the
heater body.
It is permitted to use replacement fuels with different
quality parameters and of a different granularity as
additions to the basic fuel (up to 10% with respect to
the wood chunk volume), such as waste wood.
When burning small pieces of fire wood note that
they should be separated by large fuel wood chunks.
NOTE!
The NPS series heater is not a furnace for
burning waste, and fuel that is forbidden may
not be burned in it.
NOTE!
Permanent use of certain wet fuel types, with
simultaneous maintenance of low combustion
gas temperature (less than 160 °C) will cause
faster
wear of the heater body, corrosion of the
convection ducts, the flue and tar deposits in the
combustion chamber. This is caused by
condensation of the combustion products: water,
nitrogen oxides and sulphur oxides, which
together form a very aggressive environment
facilitating faster corrosion.
As replacement fuel there may also be used a mix of
nut coal of class 24/12 at 70% with coal dust of class
21/15 at 30% according to the standards indicated
above.
5. Heater technical data
Rated power
35 kW
70 kW
Power supply
230 V 50 Hz
400 V 50 Hz
Energy consumption
1.2 A
1.6 A
Fan air flow
5500 m3/h
12500 m3/h
Width
600 mm
780 mm
Length
1000 mm
1250 mm
Height with head
1400+500 mm
1720+550 mm
Combustion rack chamber dia.
450 mm
620-mm
Combustion rack chamber height
680 mm
860 mm
Smoke stack diameter
150 mm
180 mm
Weight
200 kg
280 kg
Ventilation head rotation
Yes
Yes
Fuel
Wood/coal
Wood/coal
Burner installation option
Yes
Yes
6. Heater transport and assembly
6.1. Transport and storage
The heater units are delivered assembled on pallets,
packed in film.
Use appropriate lifting equipment to raise and lower
the heater. Before transporting the heater, it should
be protected against shifting and tilting on the
vehicle platform by means of belts, chocks or
wooden blocks
The basic fuel for FHSPN heaters is fuel wood in
chunks. It should be seasoned under a roof for a
period of at least two years at a humidity level of 15-
20%.
Air heater FHSPN 35 FHSPN 70
As replacement fuel for FHSPN type air heaters,
energy coal may be used, nut type, classes 24/12,
type 31-2, according to standard PN-91/G-04510.
The indicated designation of 24/12 concerning fuel
characteristics determines the calorific value to be
approx. 24000 kJ/kg with an ash content of 12%.
This type of fuel guarantees the maintenance of the
declared power values.

HINT!
The heater should be transported in a vertical
position!
NOTE!
The heater should be installed by a
professional plumbing company according to
the standards in force!
NOTE!
It is forbidden to install the heater outside of
the building (in the open).
Fuel
The fuel should be stored in a separate technical
storage room, close to the heater or in the room,
where the heater is located, however, not closer
than 0.5 m (two feet) from the heater.
NOTE!
It is forbidden to install a forced ventilation
system in the heater room.
Ventilation
It is forbidden to use forced ventilation in the
installation room of the heater, taking in air for
combustion from its room, and with a gravitational
combustion gas removal, and in the room in which
the intake ducts for the combustion gas lines are
located.
The use of individual forced ventilation units in
rooms directly adjacent to the room of installation of
the heater may also cause the emergence of
underpressure and uncontrolled outflow of
combustion gases from the heater into the room.
In the installation room of the heater, there must be
ensured a gravitational air supply and exhaust
system. This system may not cause the emergence
of underpressure in the room.
The air supply system should ensure an inflow or
combustion air in a volume not less than 10 cu m
per hour for each kW of installed nominal burner
power and not less than 20 cu m per hour for each
person foreseen to permanently remain in the room.
The air supply and ventilation ducts should be
protected by steel mesh and constructed in such a
way that they cannot be clogged. The placement of
the mesh units should not cause draughts to
emerge.
NOTE!
The supply of a sufficient volume of fresh air
to the heater room needs to be ensured. Lack
of sufficient fresh air supply produces the risk
of incomplete combustion and the formation
of carbon monoxide.
a safe distance of at least 1.5 metres (five
feet) be maintained from combustible
materials during installation and operation of
the heater,
FHSPN series heaters may be stored in unheated
rooms that are necessarily covered with a roof and
provided with ventilation.
Before installation, the completeness of the scope of
delivery and its technical condition need to be
inspected.
6.2. Assembly requirements
Before installation of the heater, one needs to
acquaint themselves with the requirements of this
manual and the requirements of the relevant national
provisions.
Adherence to requirements included in the manual
during assembly and use of the heater shall enable
long-term and trouble-free operation of the heater,
and shall allow one to achieve optimum thermal
parameters.
It is suggested for the heating system to be designed,
the individual devices to be chosen and assembled
by a specialised plumbing company having
appropriate permits. The installation of the device
should be preceded by consultation with a chimney
specialist and a fire safety specialist.
It is recommended, before assembly begins, to hold
a written expert opinion on the building insulation
and ventilation and a chimney opinion concerning
the ventilation of fumes (of the chimney).
6.3. Arrangement of heater in the room
FHSPN series heaters require no special foundations,
however, care must be taken for them to be
precisely levelled. The heater should stand on an even,
stable surface with sufficient load bearing capacity. In case
of insufficient load bearing capacity, measures need to be
undertaken for the required load bearing capacity to be
achieved.
The floor in the heater installation room should be made of
non-combustible materials. Should the floor be made out of
combustible materials, it should be covered with a steel
sheet with a thickness of at
least 1 mm, up to a distance of at least one metre (three
feet) from the heater outline.
When arranging the heater setup, consider fire
safety conditions. It is recommended that

for combustible materials with a flammability
rating of C3, which burn away quickly and
easily even after the flame source is
removed, this distance increases twofold, i.
e. to at least three metres (ten feet),
if the combustibility level is not known, the
safety distance also needs to be doubled.
Combustibility of
construction materials
and related products
Construction materials
and products
A - non-combustible
Sandstone, concrete,
bricks, fire-safe plaster,
masonry mortar, ceramic
tiles, granite
B - difficult to combust
Wood-cement planks,
fibreglass, mineral
insulation
C1 - difficult to
combust
Beechwood, oak wood,
plywood
C2 - combustible with
medium difficulty
Pine, larch, spruce, cork,
sawn timber, rubber floor
covering
C3 - easily combusting
Asphalt-plywood,
cellulose masses,
polyurethane,
polystyrene,
polyethylene, plastic,
PVC
The placement of the heater should take into
account the possibility of unimpeded cleaning and
direct access from all sides.
The distance of the heater front face from the
opposing wall should not be less than two metres
(seven feet), and the sides of the boiler to the walls -
not less than half a metre (two feet).
6.4. Selecting the right heater
The heating system at an industrial plant should
provide appropriate thermal comfort. According to
relevant provisions, in the working rooms a
temperature level must be secured appropriate for
the type of work being executed (according to the
work methods and the physical effort required to
carry it out), however, not being lower than 14 °C. In
working rooms, in turn, in which light physical work
is carried out, and in office rooms, the temperature
may not be lower than 18 °C. In order to choose the
heating unit correctly, the heat requirement must be
determined.
The first step is to determine the building's thermal
balance, meaning, to determine the heat losses
through walls, doors, windows, entry gates, etc.,
considering the thermal gains that may arise due to
the machinery operating inside the building, the
people or animals (i. e. in a stall) residing inside.
This procedure is quite complicated, therefore, a
formula was devised that enables one to choose a
heater properly.
P = [qv W (tw - tz)] 0.001
Where:
P- thermal heat requirement [kW]
qv - unit thermal heat power dependent on the
building's volume and estimated insulation capacity
of walls (W/m3K)
W- building volume (m3)
tw - temperature required inside the building (°C)
tz - calculated external temperature for the individual
region of the country, for Poland in line with standard
PN-82/B-02403 (°C)
Care must be taken to properly determine the unit
thermal capacity for a building. It is dependent on
the building's volume and insulation capacity.
1- increased thermal insulation capacity
2- small total window and door surface
3- large total window and door surface
Fig. 1. Unit thermal capacity depending on the
building volume and the insulation capacity of
construction divisions.

Design outside temperature and mean annual
outside temperature value depending on the
climate zone
Climate zone
Design outside
temperature in
°C
Mean annual
outside
temperature in
°C
I
-16
7.7
II
-18
7.9
III
-20
7.6
IV
-22
6.9
V
-24
5.5
Example: Building volume 1200 cu m. Required
internal temperature is 16 °C.
We read from the curve the value for qv = 1.5
W/m3K from the map we read out that Gdańsk is
located in climate zone I, so the design outside
temperature is -16 °C. We calculate:
Q = 1.5 x 1200 x [16 -(-16)] x 0.001 = 57,6 [kW]
Accordingly, one can choose either one heater with
a capacity of 60 kW or two with a capacity of 30 kW
each. Such a solution would permit flexible
placement of the heaters and directing the air flow
so that better efficiency is achieved.
This information is only general in character. We
recommend choosing a professional systems
company to select the heater unit with the right
capacity.
6.5. Connection to the electric grid
The electric grid, to which the heater shall be
connected, should terminate in an earthed socket.
Grid voltage values required by the heaters
NOTE!
Using a socket without an earth connector is
risking an electric shock!
The socket should be located at a safe distance from
the heat source. It is recommended for a separate
electric system circuit to be provided to power the
heater.
NOTE!
All electric system connections are to be
made by an electrician with the appropriate
permits.
NOTE!
The user is forbidden from any interference or
making any changes to the electric
connections!
6.6. Connecting the heater to the chimney
The device may not be connected to a chimney
together with other burners.
In case of installation of the heater in a country, the
heater chimney connection should conform to
requirements of standards and legal provisions
presently in force in the relevant target country.
The heaters should be connected to chimneys using
profiles with an appropriate cross section and shape,
made of sheet steel, insulated at the heater exhaust
gas exit and at the chimney exit, the length of which
should not exceed one metre. The connection
should have a fall towards the heater.
The height and cross-section of the chimney, and
the precision of its construction, should ensure the
maintenance of the required draught value. The
usefulness of the chimney should be confirmed by a
certified chimney specialist.
Minimum chimney height (m)
7
9
Dimensions (cm x cm)
Diameter (mm) 18x18 210 25x25 290
NOTE!
A weak draught shall cause the condensation
of water vapour on the exchanger walls, which
will bring about quick wear and damage to the
heater.
This can also cause the emergence of smoke
from behind the door and cleaning openings
of the heater.
The formula below permits easy selection of the
chimney cross-section.
F = 0.03 x Q x 0.86 / √h
Heater FHSPN35 FHSPN70
FHSPN 35 230 V / 50 Hz
FHSPN 70 400 V / 50 Hz

Where:
F - chimney cross-section (sq m)
Q - heater thermal capacity (kW)
h - height of chimney measured from the burner
level to the exit (m)
It is important for the chimney to start at floor level,
as the exhaust fumes emerging from the heater
should have the option of 'bouncing back'. It is also
important for the lower part of the chimney to have
an inspection opening that can be sealed tight.
The chimney should stand at least 1.5 metres (five
feet) above the roof surface. The walls of the
chimney should be smooth, tight, without any narrow
passages or turns and free from any other
connections. A new chimney needs to be dried and
heated sufficiently before the heater is fired. In case
of doubt, the technical condition shall be evaluated
by a chimney specialist. Steel pipe chimneys should
be taller than masonry chimneys by 15-20%.
Maintenance of the chimney duct within its
recommended limits is one of the more important
factors guaranteeing the achievement of appropriate
technical and operational parameters of the heater.
NOTE!
Due to their high effectiveness, it is
recommended to use chimney liners made of
stainless steel thermal heat-resistant steel for
7. Heater operation and maintenance
7.1. Initial heater start-up
Before start-up of the heater, inspect as follows:
chimney system tightness
chimney connection correctness
tightness of ventilator contact surfaces and
inspection openings
manner of connection to the electric grid
The boiler start-up procedure is as follows:
switch on the heater
light up the burner according to this manual
recheck heater tightness
acquaint the user with the operation of the
unit
note data in the warranty card
HINT!
The conclusion of installation and the
execution of a heating trial need to be noted in
the warranty card. The completed warranty
card should be sent by the user, as copy, to
the address of the manufacturer so the user is
registered in the company system.
7.2. Heater start-up and use (User instructions)
Before commencing burner start-up, check:
that system ducts are free from
obstructions
that the ventilation system works
properly.
1. If this is a repeated start-up, remove the ash
collected in the loading chamber. The charcoal
remaining in the chamber can form the first start-up
layer.
2. Lay out on the remains of the charcoal a layer of
wood, not filling more than 50% of the grid.
3. From the topside, lay out a layer of minute pieces
of wood with some bunched-up paper. Afterwards
add a layer of wood chippings and some pieces of
soft wood.
4. The heater should be started up by switching the
control unit on.
5. Light the paper, and after it catches fire, close the
loading door, leaving it slightly open for a few
seconds.
6. In order to ease distribution of a higher volume of
air during start-up, set the volume of primary air by
extracting and pushing in the ash tray.
7. When the wood catches fire well (after about 20-
30 minutes), fill the chamber with an appropriate
amount of wood so that the loading chamber is
approx. 60% full, and close the loading door.
8. The next steps in the burning process entail
continued supply of fuel and controlling the burning
process by adjusting the primary air volume by
extracting and pushing in the ash tray.
9. Never leave the heater unattended!
NOTE!
It is forbidden to disconnect the power supply
from the device when it is hot, because the
collected energy can damage the ventilator
and heat exchanger!
the FHSPN series heaters.

NOTE!
Components of the heater - in particular outer
covers - are hot during operation. Appropriate
caution is advised!
NOTE!
Never stand straight before the boiler when
opening doors. Risk of burns!
NOTE!
The grid chamber should always be closed,
save for a start-up period, for loading and the
removal of grid contaminants.
7.3. Periodic heater maintenance - cleaning and
upkeep
HINT!
In order to maintain appropriate combustion
efficiency, keep the convection ducts and
sheet metal inside the grid chamber
appropriately clean. Soot, dust and ash from
combustion shall reduce effectiveness and
capacity of the combustion process.
NOTE!
The operating temperature of the individual
heater units can reach up to 600 °C.
In order to clean the heater, shut it down and
wait out the time necessary for the heat
exchanger to cool down.
NOTE!
Before commencement of maintenance
procedures, disconnect the heater power
supply!
NOTE!
All activities need to be carried out with
particular care. They can only be executed by
adults. Ensure for children to stay clear and
away from the heater during its cleaning
procedure. Use gloves, safety goggles and
head protection when servicing the heater.
In the grid chamber of the heater, pay particular
attention to the precise removal of ash and slag
from the grid grooves and chamber walls. Such
cleaning should be carried out each time the
heater is started up. Before cleaning, shut off the
heater with its main switch, and wait out the
period necessary for the heat exchanger to cool
down.
The exhaust ducts, in which volatile ashes
gather, should be carried out through the
inspection openings every seven to fourteen
days, depending on the fuel quality and humidity.