HAMWORTHY HEATING LTD
41
Wessex ModuMax
mk3
Boilers
500001308/C
C1.2 Waste Gas Volume and Temperature.
It is recommended that the volume and temperature of the waste gases used for design of the flue system are as
given in the above tables.
C1.3 Materials.
Materials used for the flue system must be mechanically robust, resistant to internal and external corrosion, non
-
combustible and durable under the conditions to which they are likely to be subjected. Consideration must be
given to avoid possible freezing of condense water traps and pipework
WARNING: THE FLUE SYSTEM MUST BE SELF SUPPORTING AND NOT PRESENT
A RISK TO PEOPLE IN OR AROUND THE BUILDING.
C1.4 Suction
The maximum number of Modules firing into a common chimney is 9. (IM11/IGEUP10 states 8 for a natural draft
flue). For larger installations refer to HHL Technical.
The flue system referred to in Table C1.1 must be designed acknowledging that there is a positive pressure generated by
the boiler combustion fan. It is recommended that a draught stabiliser is fitted to the flue system where the suction
is likely to be negative at the boiler connection. Any stabiliser fitted must be in or close to the vertical chimney.
The flue system must be designed to limit the
maximum suction (cold)
to
30Pa negative
, measured at the
connection to the boiler. Should the suction be greater than 30Pa, refer to HHL technical.
This condition must then be checked
Hot
and with all boilers firing, the maximum pressure condition at the
connection to the boiler is
150Pa positive
.
In the event that the flue system when
Hot
does generate a suction, the
maximum suction is 100Pa
.
Fan Dilution
-
The design must provide for the use of balancing and trim dampers, and their location and
operation must be such that the constraints detailed above can be met. Care must be taken to ensure that the fan
performance is matched to deliver the appropriate dilution, whilst ensuring that excessive suction is not applied to
the boilers. If in doubt, refer to HHL Technical.
C1.5 Disconnection
Provisions should be made for disconnection of the flue pipe for servicing. It is advisable that bends are fitted with
removable covers for inspection and cleaning as appropriate.
C1.6 Flue Discharge
The flue system must ensure safe and efficient operation of the boiler to which it is attached, protect the
combustion process from wind effects and disperse the products of combustion to the external air. The flue must
terminate in a freely exposed position and be so situated as to prevent the products of combustion entering any
opening in a building. Where the flue diameter is less than 204mm (8”) diameter a terminal must be fitted. Where
the flue is of a larger size, consideration should be given to the fitting of a flue discharge terminal or grille to stop
ingress of birds etc.
C1.7 Surface Temperatures
Combustible materials in the vicinity of the boiler and flue shall not exceed 65°C during boiler operation. The flue
shall not be closer than 50mm to any combustible material, except where it passes through such material with a
non
-
combustible sleeve when the air gap may not be less than 25mm.
