HAMWORTHY HEATING LTD
44
PUREWELL VariHeat he
500001155/F
It is recommended that the volume and temperature of the waste gases used for design of the flue system are as
given in Table C1.
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
C1.4 Suction
The flue system must be designed acknowledging that there is a positive pressure generated by the boiler combustion
fan available to the flue system. It is recommended that a draught stabiliser is fitted to the flue system where the
draught is likely to become –ve at the boiler connection.
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.
WARNING: THE FLUE SYSTEM MUST BE SELF SUPPORTING AND NOT PRESENT
A RISK TO PEOPLE IN OR AROUND THE BUILDING.
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 170mm (7”) 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.
C1.8 Location
The flue system must not be placed or fitted where there is undue risk of accidental damage to the flue pipe or
undue danger to persons in the vicinity. Check that the flue and chimney are clear from any obstruction. Purewell
Vari
Heat he boilers are suitable for installation in a balanced compartment in accordance with the requirements of
BS 6644. Consult Hamworthy Heating Technical Department for help or assistance if in doubt.
C1.9. Condensate Discharge
Due to the high thermal efficiency of the boiler, a condensate trap is provided to connect the boiler sump to drain
so that any condensation that may occur within the boiler during start up conditions is removed. Consideration
should be given to possible freezing of condense water traps and pipework. This must be avoided at all times by
routing pipework within the building, where possible.
