Vesta 12 Duo Boiler User manual

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Product Data
Model: Vesta 12 Duo Boiler
Nominal Heat Output 12KW 35,000BTU to Water
Flue Outlet size 150mm
Flue Position Top/Rear
Max Hearth Temp 54oC
Hearth Requirement 12mm Non Combustible
Fuel Seasoned Logs 20% moisture
max
Flue pressure 10Pa
Dealer/Installer Details:
Appliance Serial Number

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Warranty
All Vesta stoves carry our 2 year standard warranty.
This warranty covers all components of the appliance apart
from the heat reflective bricks and the door rope seal. These
parts are deemed replaceable during the normal working life of
the appliance and can be purchased from Vesta direct
www.vestastoves.co.uk
Annual servicing
It is recommended that all wood burning appliances are ser-
viced by a competent person as least once per year. This can
be carried out by the chimney sweep during the annual clean-
ing of the flue ways.

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General Safety Advice
Properly installed, operated and maintained, this appliance will not
emit fumes into the dwelling. However occasional fumes from de-
ashing and re-fuelling may occur. Persistent fume emission is poten-
ally dangerous and must not be tolerated. If fume emission does
persist, open doors and windows to venlate the room. Let the re
burn out or eject and safely dispose of fuel from the appliance. Once
the re is cold, check
the ue and chimney for blockages and clean if required. Do not
aempt to relight the re unl the cause of the fume emission has
been idened and corrected. Seek expert advice if necessary.
· Do not t an extractor fan in the same room as the appliance.
· An adequate air supply for combuson and venlaon is essenal
in accordance with Building Regulaons
Document J Secon 2. Air openings provided for this purpose must
not be restricted.
· It is important that ue ways are cleaned frequently and the chim-
ney swept regularly. Also the stove must be
maintained in good mechanical order. The chimney should be swept
at least once per year for smokeless fuel
and a minimum of twice per year for other fuels.
· If the chimney was previously used for an open re, it is possible
that the higher ue gas temperatures generated by the stove may
loosen deposits that were rmly adhering to the inner surface of the
chimney and cause blockage of the ue pipe. We recommend that in
such a situaon a second sweeping of the chimney should be carried
out within one month of regular use of the stove aer installaon.
Also, lock open or remove any exisng dampers in the ue way.
· Should it be likely that children, aged or inrm people approach
the re, then a reguard should be ed.
· Avoid the use of aerosol sprays in the vicinity of the stove when it
is in operaon.

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Vesta 12 DUO
Wood Burning Stove
Operang Instrucons

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Building regulaons
Installaon of the Vesta woodburning stove must comply
with all local building regulaons, including those referring
to naonal and European standards. It is a good idea to con-
sult your local chimney sweep to check the suitability of the
chinmney and ensure there is adequate updra and suggest
any remedies to potenal chimney problems. Document J of
the Building Regulaons contains further informaon regard-
ing the installaon of solid fuel appliances and can be
viewed here : www.odpm.gov.uk or follow the link on our
website.
Lighng the stove
When lighng the stove for the rst me it should not be
stoked excessively as all the materials must be given me to
adapt to the eects of heat. The paint will take some me to
fully cure and during this period some odours will be evi-
dent. It is recommended that doors or windows should be
opened the rst me the stove is red.
Before lighng check the rebricks and other internal com-
ponents are in posion and that all packaging has been re-
moved.
(Continued on page 7)

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 Open the top and boom air control fully
This is done by sliding the boom air control into
the central posion, and rotang the top air con- trol
unl the slots are aligned. See Fig 1.
 Place rolled up/scrunched newspaper into the back of
the appliance and stack small kindling/scks into the
back of the re. A few larger pieces of fuel can be added
to each side of the pile. Firelighters can be used if re-
quired.
 Larger pieces of wood can now be added slowly towards
the back of the re. Adding too much cold fuel will put
out the re.
 The boom air control can now be closed down and the
re regulated by means of the airwash. Opening the
boom control slightly helps to draw the re into the
stove and will allow the door to be opened for loading
more easily.
Lighng a woodburner is a skill and is learned over the st
few weeks of owning your woodburner, It can be frustrang
at rst unl you get to know your re and your chimney……...

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Lighng the stove (cont)
Do not run the appliance with the door open. This reduces the e-
ciency of the burn and you will use much more fuel.
Tips
The rst stage of the re, just aer lighng, is usually the smokiest
because the cold wood and cold stove take heat away from the
ames. During this stage, ensure both air inlets of the stove are fully
open to get a hot ame. It might appear that this inial hot burn lets
too much heat go up the chimney, but it is a necessary part of an
ecient re. The extra heat “primes” the chimney to produce a
strong dra, and helps keep the ue clean by loosening creosote
that might have been deposited by the previous re. The hot inial
burn also drives moisture out of the rewood and gives an ignion
source for the smoke that is released from the wood.
Make small changes. Do not try to add too much fuel at once, the
fuel should not be stacked higher than the top of the back re brick.
Adding fuel gradually will help maintain a steady temperature and
burning rate so that the stove burns eciently and cleanly. Adding a
large amount of fuel all at once will dramacally reduce the temper-
ature inside the stove. Aer adding a large piece of wood/log it is a
good idea to increase the top air opening slightly more unl the new
fuel begins to burn and the stove returns to temperature.
This also applies to the air controls. Adjusng them gradually will
help maintain a steady combuson rate.
Do not run the stove with the top air control fully closed. The top air
control supplies air for the glass ‘air shield’ system. The further

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open the top air control the more eecve the air shield system.
Use a piece of newspaper to wipe the inside of the window glass be-
fore lighng the stove each me to prevent the gradual build up of
deposits.
Small, hot res are more ecient than large slumbering res. Most
of the energy in burning wood is released as a bright ame. The tur-
bulence in the ames creates good mixing between the combuson
air and the gases that are released from the wood as it heats up. The
heat of the re ignites and burns these gases. In contrast, the dense
smoke from a slow, smouldering re is potenal heat energy that es-
capes up the chimney and either clings to the chimney ue as creo-
sote or pollutes the outdoor air. Therefore, to gain the most heat
from each load of rewood, the wood should be aming throughout
the burn cycle unl it is reduced to ash.
If you do a fair bit of slow woodburning, it is good pracce to burn a
good, hot stove at regular intervals to keep your chimney dry and
prevent the build up of tar.
When refuelling, place wood towards the back of the stove where it
will burn hoer and more eciently. Try to place logs length ways so
that any sping from the end grain does not go onto the glass win-
dow. The fuel should not be stacked higher than the top of the back
re brick. Once the stove is hot and running steady, it should be pos-
sible to maintain the nominal output by refuelling approximately
once an hour.
Notes on woodburning
Wood burns most eciently when the air for combuson is supplied
from above the re bed rather than below. The air supplied above
the re bed provides the oxygen necessary for the volale gases
(smoke), given o by the wood as it heats, to combust. This ensures
that the gases are burnt and used to heat the appliance instead of

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being wasted up the chimney or condensing and forming tarry de-
posits inside the stove, the ue pipe or on the door glass. Running
the stove with only the boom air control open in a Vesta stove
does not supply air to the base of the re but adds oxygen to the top
of the re at the back of the stove. This helps to draw the re into
the back of the stove away from the glass.
Slow woodburning
To slow the burning rate and output from the stove reduce the air
entering the stove via the air controls. The re must be well estab-
lished and the stove hot before a minimum combuson rate is
aempted. Note that if the air supply is restricted too much the re
will burn dirty and ineciently. Slow overnight burning is not ad-
vised for this reason.
Venlaon
The stove requires an adequate air supply for successful operaon
(see Installaon secon of these instrucons for more details). En-
sure that air bricks or grilles supplied for this purpose are not
blocked. Be aware that the operaon of exhaust fans or other appli-
ances that compete for venlaon in the vicinity may aect the per-
formance of the stove.
Running temperature
To get the best results from your stove it is recommended that a
wood stove thermometer be ed to the ue pipe just above the
stove. Most thermometers are magnec and if aached to the sin-
gle wall ue pipe just above your stove will give a good indicaon of
the ue gas temperatures.
Flue thermometers are available from www.vestastoves.co.uk

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Flue Temperature Ranges.
150 °C - 300°C
The ue gases should be in this temperature band for the safest,
most ecient and most economical operaon of your stove.
Below 150°C
This is below the condensaon point of wood gases and may cause
the build up of tar in the chimney, dirty the stove glass and result in
the inecient burning of fuel.
Above 300 °C
Too hot. Heat will be wasted up the chimney. Excess heat may dam-
age the stove or ignite an exisng accumulaon of tar resulng in a
chimney re.
Over heang
If the stove is allowed to get too hot and is over heang, close both
of the air controls fully using the tool, keep the re door closed and
let the re burn down.
Chimney Fire
In the event of a chimney re dial 999 and ask for the Fire Service.
Fully close the air controls on the stove and keep the re door shut.
Move any combusbles away from the stove and the chimney
breast. Also check other rooms that the chimney passes through and
move furniture and other combusbles away from the chimney here
too.
Before using the stove again aer a chimney re have the chimney
cleaned and inspected by a qualied person.
Cleaning the stove

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We recommend using Thermacure stove glass cleaner. This is availa-
ble from www.vestastoves.com
Only clean the glass when the stove is cold.
The painted surface of the stove can be wiped down with a dry cloth
only when cold. The paint can be easily damaged if touched when
hot for the rst few rings. Touching up the stove is easy and can be
done with Thermacure stove paint available from
www.vestastoves.com
Types of fuel
Wood needs to be well seasoned before it is burnt. Dierent woods
take varying amounts of me to season but, as a general guide, be-
fore being used in a stove, wood should be cut to length, split and
then stacked under cover (with the sides open to the air) for at least
a year. Wood is ready for burning when radial cracks appear in the
end of the logs and the water content is no higher than 20%. It is
then good pracce to have it in the log basket, inside the house, for
a few days before it is actually used in the stove. The internal width
of the rebox is 350mm and so rewood should be no longer than
this.
Do not burn unseasoned wood in your woodburner. Do not burn
parcle board, lacquered, painted or treated wood, plascs, rubber
or liquid fuels. The stove is not suitable for burning solid fuel ie. bri-
quees\ coal\coke\smokeless fuel. The stove should not be used as
an incinerator.
Remember water doesn't burn so use dry fuel. Wet wood causes
black glass and tar build up inside chimneys and will damage your
appliance.
Ashes

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Vesta 12 DUO
Wood Burning Stove
Installaon Instrucons

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Installaon
Building regulaons
Installaon of the Vesta woodburning stove must comply with all lo-
cal building regulaons, including those referring to naonal and Eu-
ropean standards. It is a good idea to consult your local chimney
sweep to check the suitability of the chinmney and ensure there is
adequate updra and suggest any remedies to potenal chimney
problems. Document J of the Building Regulaons contains further
informaon regarding the installaon of solid fuel appliances and
can be viewed here : www.odpm.gov.uk or follow the link on the
Vesta website.
Venlaon
There must be a constant supply of fresh air to the room in which
the stove is to be installed. Fixed venlaon must be provided when
installing any solid fuel stove which has an output higher than 5kws.
For each kilowa above ve, 1500 sq mm (2.56 sq ins) of venlaon
is required. This stove has a maximum output of 10kws and so there
should be xed venlaon of a minimum 1500 sq mm. Any airbricks
or grilles ed for this purpose should be posioned so that they
are not liable to blockage. If other appliances requiring venlaon
operate in the vicinity of the stove then there must be adequate
venlaon to provide for both appliances operang simultaneously.
NOTE Extractor fans when operang in the same room or space as
the stove, may cause problems.
Load-bearing capacity of the oor
Before installing the stove, you must ensure that the load-bearing
capacity of the oor can withstand the weight of the stove and any
ue pipe and connecons. The weight of the stove is 155KG.

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Hearth
The stove should always be installed on a non-combusble hearth.
The hearth should extend to a distance of 225mm in front of the
stove and 150 mm to each side measured from the door of the com-
buson chamber. See document J of the building regulaons for
more informaon on hearth requirements.
Clearances
The minimum distance to combusble materials should be 500mm
at the back of the stove and 150mm to the sides of the stove. Adja-
cent walls should be of suitable non-combusble construcon, pref-
erably brickwork. Make sure that there is a gap between an un-
insulated ue pipe and any combusble material. This gap must be
at least 3 x the outside diameter of the ue pipe (375mm for 5” sin-
gle wall ue pipe), or 1.5 x the ue diameter (375mm for 5” single
wall ue pipe) to non combusble surface. A minimum clearance of
80mm around the sides and back of the stove is recommended to
allow for air movement and heat from the stove to enter the room.
Chimney requirements
An exisng chimney or a new ue or chimney installaon should be
given a visual inspecon to check that it is in good order, clear of ob-
strucons and is of a suitable size and type for the stove. It may be
necessary to sweep the ue (which should always be done anyway
before ng a stove or lining a chimney) and also, if necessary, to
do a smoke test to check for gas ghtness and chimney dra. The
chimney or ue must not serve any other appliance.
For nominal heat output:

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The minimum ue draught required is 12PA.
The ue gas mass ow will be 6.6g/s.
The ue gas temperature directly down of the socket will be approx-
imately 262 deg C.
Air damper
Flue draught stabilisers can be used if necessary with this appliance.
Flue connecon
The stoves has both rear and top ue connecon. The ue blanking
plate should be posioned over which ever outlet is not being used,
posion the blanking plate over the outlet and use the access via
the opposite ue outlet to x the clamp to the back of it, see Figure
4. Posion the stove and seal the ue connecons with re cement
or a high temperature rope seal. Care should be taken not to allow
re cement to come into contact with the paintwork on either the
stove or the ue pipe. A rear ue can be secured to the stove by us-
ing 4 M5 nuts and bolts. The ue collar is predrilled to accept these.
Boiler System (Max Output 35,000Bu)
This installaon should be in accordance with BS 5449 code of prac
ses. It must include agravity circuit with an
expansion tank open to the atmosphere.
When installing this appliance on agravity circuit, the system should
consist of atank/indirect cylinder xed in
an upright posion and should be connected to the boiler by 28mm
pipe both ow and return. The pipes
should not exceed 7.8m in length. The shorter the run of pipe work t
he more eecve the appliance is going to
be at heang the water. The cylinder and pipe work should be

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lagged to minimise the heat loss in the system. A
heat leak radiator must be incorporated into the system to dissipate
any excess heat produced from the boiler
when connected demands are low. The heat leak must comprise am
inimum of 10% of the boiler output. Fit
the heat leak radiator in the gravity circuit using 22mm pipe reducin
g15mm for no more than 300mm before
the radiator.
This Duo Stove contains twin stainless steel heat exchangers. The
unit should not be run whilst the boilers are dry. The heat exchang-
ers are not linked internally and can be either linked by means of
pipe work or connected separately to dierent parts of a heang cir-
cuit.
28mm BSP Standard Fittings
INLETS
28mm BSP Standard Fittings
Outlets

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Fault Cause Resolution
Black Glass Wet Fuel Season Wood foe at least 12-18
Months.
Low Flue Pressure Consult Installer
Damaged Rope Seal Fit new rope seal
Blocked Flue Consult chimney sweep/Installer
Fire goes out Wet wood, Season Wood foe at least 12-18
Months.
Low Flue Pressure Consult installer, this could be due
to downdraught or you may require
a liner
Blocked Flue Consult chimney sweep.
No combustion Air Fit combustion air brick in line with
document J of Building regulations
Cant slow
down burn
rate
Damaged rope seal Replace rope seal using HT Silicone
Door Handle Loose Adjust collar tension using allen key
Flue Blanking Plate Loose Realign flue blanking plate and seal
all joints with fire cement.
Firebricks
cracking after
1-6 months
Wet fuel, careless loading Ensure fuel is dry. Do not load fuel
by throwing into the fire
Paint blister-
ing
Fire cement contact, burning too
hot.
Rub down back to bear metal using
wire wool or 240 grit sand paper
then re-coat using Thermacure HT
paint.
Troubleshoong

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Illustraons
Open
Close
Central posion is
Fig. 1
Fig. 2
Shown in fully open
posion
Insert tool to turn
when hot

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Illustraons
Fig 3.
Flue Blanking plate xing
from inside aer removing
bricks
Fig 4.
Levelling legs on the rear
legs can be adjusted to suit