Installation & Servicing Instructions Rinnai E-Series
35
Calculation of equivalent length vent system
Choose the vent type and
fi
ll out the corresponding table.
* See equivalent length tables above.
Example of calculation:
Twin tube (parallel) with terminal
Combustion air length
: 24 ft
with elbow 3 x 90°
Vent length
: 24 ft
with elbow 2 x 90°, elbow 2 x 45°
Calculation:
Equivalent Air Length
: (24+3x6+2) x 0.5
= 23 ft
Equivalent Vent Length
: (24+2x6+2x3+2) x 0.5
= 23 ft +Total
= 46 ft.
6.7.6 Combustion air and vent piping lengths.
In the table below you will
fi
nd the maximum equivalent pipe length of the vent/air
system based on 3" diameter. These lengths are for single pipe (room air) and twin
pipe.
Equivalent vent length
table 8
Boiler type
3” Max Vent equivalent length
3” Max Air equivalent length
E50C
100 feet
100 feet
Parallel system
Length tube
Number of
elbows 90°
x 6*
Number of
elbows 45°
x 3*
Concentric
terminal
Add 5 ft.*
Total
Multiply with
factor
Equivalent
length
Combustion air
ft
ft
ft
ft
ft
0.5
ft
Vent
ft
ft
ft
ft
ft
0.5
ft
ft
Total equivalent length
Equivalent friction loss of PVC/CPVC
table 9
Fittings or Piping Equivalent PVC
feet
m
45 degree elbow
3
0.91
90 degree elbow
6
1.83
plastic pipe per foot
1
0.30
concentric vent kit
3
0.91
Centrotherm PPs Equivalent lengths for piping fittings
feet
meters
45 degree elbow
6
1,83
87 degree long elbow
12
3,66
Termination Tee
12
3,66
Twin Pipe to Concentric Adapter
4
1,22
Low profile wall termination
12
3,66
Velocity Cone
12
3,66
Equivalent friction loss of Centrotherm PPC
table 9a
Concentric system
Length concentric
tube, boiler to roof
horizontal
Number of
elbows 90°
x 6*
Number of
elbows 45°
x 3*
Concentric
terminal
Add 2 ft.*
Total
Multiply with
factor
Total equivalent
length
ft
ft
ft
ft
ft
1.0
ft
