Flue System - Bosch WORCESTER DANESMOOR UTILITY 12/14 Installation And Servicing Instructions

7. Flue System

A flue system must be provided in accordance with BS5410 and
the current Building Regulations. (See Section 1.4).
7.1 CONVENTIONAL FLUE (CF).
See Fig. 4.
Conventional Flue Diameters: 12/14 – 100 mm (4 in.)
NOTE: On 50/70 models with flue lengths longer than 12
meters it is recommended that 175mm (7in.) flue pipe is used
from the boiler.
NOTE: External flues systems must be of the insulated flue type.
Fig. 4. Flue Installation.
The boiler is fitted with a conventional flue locating spigot. The
flue pipe fits into the spigot and should be correctly sealed with
fire cement.
NOTE: The size of the flue must never be reduced from the take-
off diameter. An increase in flue size is permissible provided that
the joint is sealed correctly.
When installed the flue should be vertical and contain as few
bends as possible. Where bends are necessary, a maximum of
two are permitted and 135 degree bends should be used.
All brick and masonry chimneys should be lined with a suitable
non-combustible material, properly jointed and able to with-
stand the effects of the working temperature of the appliance
and any condensate which may form.
15/19 – 100 mm (4 in.)
20/25 – 100 mm (4 in.)
26/32 – 125 mm (5 in.)
32/50 – 125 mm (5 in.)
50/70 – 150 mm (6 in.)
Down-draught conditions will adversely affect the operation of the boil-
er and must be avoided. Where possible the flue should be extended
beyond the apex of the roof and should always be taken beyond the
eaves of the building. Where down-draught is experienced a suitable
anti down-draught terminal should be fitted to the flue termination.
The natural flue draught must be checked in the flue pipe imme-
diately above the appliance or in the hole provided in the flue
outlet plate. The flue draught should be no less than 0.75 mm
W.g. and no greater than 5.1 mm W.g. If a flue draught greater
than 5.1 mm W.g. is experienced a draught stabiliser should be
introduced into the flue and adjusted to achieve a flue draught
within the specified range.
7.2 Low Level Discharge (LLD)
(See Fig. 5).
The low level flue kit is not designed for use with this appliance
as there is no provision for installation of the flue gas purge
timer. However, where fume odour will not present a problem
(eg boilerhouse/outhouse) the flue kit may be used without the
purge unit. Alternatively, a standard Danesmoor kitchen
appliance or room-sealed utility model should be used.
The LLD kit converts the 12/14, 15/19, 20/25 and 26/32
conventional flue appliances to discharge the combustion
products from the rear of the appliance at low level.
The flue spigot should be removed from the flue outlet plate by
Fig. 5. Flue Installation (Rear Discharge).
FLUE GUARD
766
80
min.
undoing the three retaining screws and the hole blanked off with
the plate provided in the kit.
Detailed instructions for converting the appliance to low level
discharge are supplied with the conversion kit.
NOTE: Under no circumstances may 35 Second Gas Oil be
burned with this type of flue terminal arrangement.
7.3 ROOM SEALED BALANCED FLUE MODEL (RS).
The appliance is supplied ready for installation as a low level
discharge balanced flue system by the simple addition of one of
the flue terminal kit options shown in Fig. 6.
Details of the installation procedure are included in the Flue
Terminal Installation instructions supplied with the terminal kit.
Alternatively, a range of room-sealed balanced flue kits are available
to convert the appliance to discharge the flue products to the left,
right, at a higher level, or vertically up to a roof height of 4.5 metres.
7.4 Siting the flue terminal
1. The flue terminal must be located in a suitable position, as
shown in Fig. 7, such that the products of combustion can be
freely dispersed without the possibility of the gases entering the
dwelling or that of a neighbouring dwelling.
2. Discharge of flue gases into car ports or narrow passageways
is not recommended.
9
See Fig. 7 for
flue terminating
positions.