Component
Internal Size (mm)
Resistance factor (Ke)
100
0.78
125
025
100
1.22
125
0.5
100
0.61
125
0.25
100GCI
0.6
125 GCI
0.25
Inlet resistance of flue (Ki)
Outlet resistance of flue (Ko)
100mm spigot
2.5
100mm flue
2.5
125mm spigot
1.0
125mm flue
1.0
Pipe
90˚ bend
135˚ bend
Terminal
per fitting
per fitting
per fitting
per meter
18 Method for calculating equivalent flue resistance - Appendix 1
Description
Part Number
Igniter probes
201284
Burner head
200974
Orifice plate gaskets
201208
Combustion fan
2501
Pactrol control box
2015
Gas valve
2052
Red neon
2180
Amber neon
2175
Wiring harness
900224
Neon lamp wiring harness
200254
Burner head wiring
assembly
900225
3 pin mains socket
2135-5
3 pin fan socket
3123-5
Silicone tube
2198
Fan air inlet
201125
Burner orifice plate
201063-08
Injector
201007-24
Vacuum switch
201013
17 Spare parts
1 4
H
e
= H
a
x
The formula for calculating the equivalent flue size is as follows:
(Ki + Ko) e
(Ki + Ko)a - KeHa + K
where
He is the height of the equivalent flue
Ha is the vertical height of the actual or proposed flue measured from the flue spigot
Ki
is the inlet resistance of the flue
Ko is the outlet resistance from the flue subscript ‘e’ refers to the equivalent flue diameter subscript ‘a’ refers to the
actual or proposed flue diameter
Ke is the resistance per unit length of the equivalent flue
K is the resistance (other than the inlet and outlet resistances) of the actual or proposed flue
Note K and K are obtained from the table above
