7
Purevision Freestanding
Issue 02 01/14
firmly adhered, with the consequent risk of flue blockage. It is therefore recommended that the
chimney be swept a second time within a month of regular use after installation.
If you have any doubts about the suitability of your chimney, consult your local dealer/stockist
or chimney specialist. If there is no existing chimney then either a solid fuel compatible
prefabricated block chimney or a twin-walled insulated stainless steel flue to BS 4543 can be
used. These chimneys must be fitted in accordance with the manufacturer’s instructions and
Building Regulations.
5.2.
Ventilation
Document J of the Building Regulations states that purpose provided ventilation is not required
in England and Wales unless the appliance nominal rated output is greater than 5kW. Over 5kW
5.5 cm
2
of ventilation (550mm
2
) is required for every kW output above 5. For example 6.5 kW
requires 8.25 cm
2
and 8 kW needs 16.5cm
2
. In any case, if difficulty in starting the fire or any
excessive fuming is experienced, ventilation must be put in place as required to eliminate these
flue problems. If a flue draught stabiliser is fitted then extra ventilation is required. See
Document J of the Building Regulations for detailed guidance especially in new build properties.
A specifically designed direct outside air connection may be used with these stoves to provide
appropriate levels of ventilation (significantly in excess of the above requirements) directly to
the stove and chimney as follows. NOTE: As of early 2014 an ADJ vent is still required even if
using an outside air connection.
5.3.
Direct Outside Air Connection
Purevision stoves are supplied with the facility of using a dedicated 100mm diameter direct
connection duct through a suitable route to the outside air. It can either be connected to the
rear or the underside of the stove and should be fitted at the time of stove installation. Only the
approved kit for Purevision stoves should be used. This is designed to supply the necessary air
for safe combustion and operation of the stove –
providing the flue, chimney and ventilation
duct are working correctly and properly maintained clear of obstructions or leaks etc.
Instructions for installation are provided with the dedicated kit supplied. NOTE: As of early 2014
an ADJ vent is still required even if using an outside air connection.
5.4.
Flue Draught
A flue draught at the flue collar of minimum 2.2mm to a maximum 3.5mm water gauge (22 to
35 Pascals) is required for satisfactory appliance performance. This relates to 12-25 Pascals at
the tapping on EN13240/13229 test rigs. The flue draught should be checked under fire at high
output and, if it exceeds the recommended maximum, a draught stabiliser must be fitted so
that the rate of burning can be controlled to prevent over-firing.
5.5.
Connection to the Chimney
This appliance is
not
suitable for use in a shared flue.
A suitable 5” flexible flue liner is permitted be used on Purevision stoves providing that they
only burn smokeless fuel or seasoned wood logs with the air limiter fitted in in full accordance
with the wood burning instructions.
An existing fireplace opening can be bricked up or sealed with a register plate. A short length of
suitable quality rigid flue pipe of a minimum 125mm internal diameter may then be used to
connect the stove to the chimney. A maximum of 150mm horizontal flue pipe can be used. This
flue pipe should conform to Building Regulations. Ensure that the pipe end is no closer than
76mm to the side or rear chimney walls.