HAMWORTHY HEATING LTD
43
PUREWELL VariHeat he
500001155/F
APPENDIX C - FLUE DATA
FLUE DATA
Model
65he
85he
105he
Nominal Flue Diameter
-
mm
100
Max back pressure allowable at flue outlet - mbar
0.9
Approx. Flue Gas Temperature 82/71°C
- °C (Gross)
158
190
146
Approx. Flue Gas Volume @ 9.5 % CO
2
- m
3
/h*
103.00
123.50 156.00
125he
175
188.00
1.5
1.9
2.5
Natural Gas
C1.0 FLUE SYSTEM
1. Detailed recommendations for flue systems are given in BS 6644, and IGE/UP/10. All flue discharges for plant
exceeding 135kW net input must comply with the third edition of the 1956 Clean Air Act Chimney Memorandum.
WARNING: THE FLUE DISCHARGE FROM A VARIHEAT BOILER MAY GENERATE A
PLUME ON START UP AT THE TERMINAL EXIT. THIS MUST BE CONSIDERED WITH
REGARD TO TERMINAL LOCATION AND ADJACENT BUILDING FABRIC.
C1.1 General Requirements
The Hamworthy Purewell
Variheat he
series of boilers are designed to be used with natural draught flues.
Flue systems should be designed in accordance with regulations and with reference to BS6644 and
IG/UP/10. These boilers are type B23 only (air intake from ventilated plant room and discharged via
vertical flue). See Fig C1.2.
The following points should be noted:
a. Due to the high thermal efficiency of the boiler condensation in the flue may occur. It is strongly recommended
that twin wall or insulated flue pipe is used on all external flue installations.
b. Care should be taken to ensure that the flue is installed such that any condensation is continuously drained. All
flues should have a maximum slope of 2° upwards in the direction of the exhaust gas flow (no horizontal
sections). All joints should be such that any condensation is directed back down the slope to an open drain
connection in the flue. The drain pipe must be manufactured from a corrosion resistant material and be at least
15mm diameter. It must also have a fall of at least 2-3° (approx. 30-50mm per meter) and connect to a drain via a
waste trap.
c. Boiler flue outlet sizes -
The connection to the boiler is suitable for 100mm flue duct, for connection to an open flue (chimney) system . The resistance
and maximum length of the flue system components is detailed in Figure C1.1.
A flue system designed with the same diameter as the boiler flue outlet may not provide satisfactory performance
in all applications. Conversely a flue system designed with a smaller diameter than the boiler flue outlet may
provide satisfactory performance. Consideration must be given to the correct calculation of the required flue size.
If in any doubt consult Hamworthy Heating Ltd who can supply a full flue design and installation service.
C1.2 Waste Gas Volume and Temperature.
Figure C1—Flue Data
*
Note:-
Flue gas volumes are corrected to a flue gas temperature of 15°C and barometric pressure of
1013.25mbar.
