HAMWORTHY HEATING LTD
61
MILBORNE
500001130/J
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 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.
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. Milborne
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, condensation will occur within the boiler casing during firing from
cold conditions. A drain with an integral trap is fitted to each module suitable for connection to a 20mm plastic
waste pipe (not Hamworthy Heating Ltd supply), which must be connected to a tundish (not Hamworthy Heating
Ltd supply). Discharge piping from a tundish should be of
synthetic material due to the mild acidity of the condensate
(pH3-5), with all discharge piping having a minimum fall of
30mm/m away from the boiler. 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.
In addition to the above, should the plastic flue system
supplied discharge into a metallic chimney system, any
condensate formed in the chimney MUST NOT drain back
through the plastic components to the boiler. A separate
drain for the chimney system must be provided.
Module
kW
Equivalent lengths (m)
Flue
pressure
(Pa)
Max
length
45° Bend 90° Bend
38 40 1.0 3.0
410
50 31 1.0 3.0
560
125mm
1.3 5.3
160mm
1.7 7.6
Note:
flue pressure quoted at full output
Figure C1.1 - 50mm Flue equivalent lengths
No. Of
Modules
Nominal
cascade
output
kW 125mm
160mm
2*38 76 428 n/a
3*38 112 176 n/a
4*38 150 103 n/a
5*38 187 65 n/a
6*38 225 45 n/a
2*50 100 300 n/a
3*50 150 134 n/a
4*50 200 75 n/a
5*50 250 47 150
6*50 300 33 105
7*50 350 n/a 78
8*50 400 n/a 60
Maximum length (m)
of open flue system
B
23
incl. header
9*50 450 n/a 46
10*50 500 n/a 38
Figure C1.2 - 125/160mm Maximum flue lengths
