4
The outlet from the chimney should be above the roof of the building in accordance with the provisions of Building
Regulations Approved Document J. If installation is into an existing chimney then it must be sound and have no cracks or
other faults which might allow fumes into the house. Older properties, especially, may have chimney faults or the cross
section may be too large .
Mendip Stoves recommend the use of a solid fuel flue lining system for all installation into existing chimneys. All chimney
systems must be used in accordance with Building Regulations Approved Document J.
If an existing chimney is used the chimney must be clear of obstruction and be swept clean immediately before installation
of the stove. The chimney should be tested to confirm the chimney will provide the correct chimney pressure for the stove.
If the stove is fitted in place of an open fire the chimney should be swept one month after installation to clear any soot falls
which may have occurred due to the difference in combustion between the stove and the open fire. If there is no existing
chimney then either a prefabricated block chimney in accordance with Building Regulations Approved Document J or a twin
walled insulated stainless steel flue to BS 1856-1 . These chimneys must be fitted in accordance with the manufacturer’s
instructions and Building Regulations. A single wall metal flue pipe is suitable for connecting the stove to the chimney but
is not suitable for using for the complete chimney. The chimney and connecting flue pipe must have a minimum diameter
of 150 mm and its dimension should be not less than the size of the outlet socket of the stove. Any bend in the chimney or
connecting flue pipe should not exceed 45
°
. 90
°
bends should not be used other than within 150 mm of stove rear flue
outlet.
FLUE & CHIMNEY CONNECTION TO STOVE
Tested Gas flow rates flue
gas temperatures
Flue gas flow rate
Wood /coal
Test flue gas temperature
wood /coal
@ pascals of pressure
Christon 400
4.0/4.7g/sec
244/240deg C
12 pa
Chimney Connection
In order for the stove to perform satisfactorily the chimney height must be sufficient to ensure an adequate
draught to clear the products of combustion and prevent smoke problems into the room.
A chimney height of not less than 4.5 metres measured vertically from the outlet of the stove to the top of the chimney
should be satisfactory. Alternatively the calculation procedure given in BS5854:1980 may be used as the basis for deciding
whether a particular chimney design will provide sufficient draught.
If it is found that there is excessive draught in the chimney then either an adjustable flue damper or alternately a draught
stabiliser should be fitted. The adjustable flue damper should not close off the flue entirely but should in its closed position
leave a minimum continuous opening free area of at least 20 % of the total cross sectional area of the flue or flue pipe.
Adequate provision e.g. easily accessible soot door or doors must be provided for sweeping the chimney and connecting flue
pipe.
Your appliance needs to be maintained routinely, the throat plate/baffle should be cleaned regularly (monthly) . The flue
pipe can be cleaned using a flexible brush. Only Use a dry cloth on external surfaces. Over time the glass may become dirty,
clean with a damp cloth and polish off with damp cloth. If the stove has not been used for some time the flue should be
checked for blockages before use. Do not modify the appliance; only use spares authorised by the manufacturer.
