HAMWORTHY HEATING LTD
49
PUREWELL
Vari
Heat he
500001170/K
APPENDIX C - FLUE DATA
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 WILL GENERATE A
PLUME AT THE TERMINAL EXIT. THIS MUST BE CONSIDERED WITH REGARD TO
TERMINAL LOCATION AND ADJACENT BUILDING FABRIC.
C1.1 General Requirements
For single boiler installations only the Purewell VariHeat
c
series of boilers are designed to be used with a forced
draught flue system. Flue systems should be designed in accordance with regulations and with reference to BS
6644 and IGE/UP/10.
Open (Natural draught ) Flue.
Type B23: Intake from ventilated plant room and discharge via vertical flue. – Fig C1.2
The connection to the boiler is suitable for 150mm 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
The following points should be noted:
a. Due to the high thermal efficiency of the boiler condensation in the flue will 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 - A flue system designed with the same diameter as the boiler flue outlet may not provide
satisfactory performance in all applications. 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.
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 above.
Figure C1—Flue Data
*
Note:-
Flue gas volumes are corrected to a flue gas temperature of 15°C and barometric pressure of
1013.25mbar.
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