Combustion Air And Vent Piping Lengths - Rinnai E50C Installation & Servicing Instructions Manual

6.7.6 Combustion air and vent piping lengths.

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