Rinnai c199e, Installation And Operation Manual

Page: 26 / 144

26 C199 Manual
Exhaust and Combustion Air Intake Pipe Diameters and
Maximum Lengths:

For PVC/CPVC vent systems reduce the maximum
allowable length for each elbow and termination type
as follows:

Vent and combustion air intake pipe diameters to be as
specified in the maximum equivalent vent length tables
of this document.

Do not exceed vent and combustion air intake pipe
MAXIMUM lengths (Lengths are specific to models and
fuel type).

2.5 feet for every 45° elbow.

5 feet for every 90° elbow.

Termination (refer to the Approved Vent
Component table of this section)
IMPORTANT CONSIDERATIONS FOR LOCATION (continued):
There are two options for determining the vent lengths/
components necessary for the installation.
Option 1: The installer can use the vent length calculation
sheet (below), filling in the quantity of the vent components
in order to calculate the total equivalent vent lengths.
Option 2: The installer can use the maximum vent lengths
tables on the next pages to determine the amount of
straight pipe that can be used with a specific termination
type and quantity of elbows.
Determining Total System Equivalent Length
(A blank copy of the Equivalent Vent Length Calculation Sheet is located at the end of this section)
Ensure SW1 in DIPSW 1 is in OFF position if vent length is greater than 21ft (6.4m).
Calculation of equivalent piping lengths for venting system:
Choose the vent type and fill out the calculation sheet
below. When determining equivalent combustion air and
vent length, add 5 feet for each 90° elbow, 2.5 feet for each
45° elbow.
OPTION 1:
Example of calculation (assume 3” diameter pipes for
natural gas unit):

Twin pipe (parallel) with snorkel terminal

Combustion air pipe length: 40 ft straight pipe with 3 x
90° elbows

Exhaust pipe length: 40 ft straight pipe with 3 x 90°
elbows
(include all interior and exterior elbows)

Snorkel Termination: 10 equivalent feet (reference
Approved PVC/CPVC Termination Components table)
Calculation:

Equivalent Combustion air pipe length: [40+(3 X 5)+10]
= 65 ft

Equivalent Vent Length: [40+(3 X 5)+10] = 65 ft

Total = 65 ft. for both exhaust and combustion air
pipes, which is the maximum allowable vent length for
3” PVC/CPVC on a natural gas unit. If longer lengths
are required, go to the 4” diameter pipe configuration
which is certified for up to 100 equivalent feet.
Fitting / Termination Type
Number of
fittings
Equivalent Vent
Length
Total Equivalent
Length
1) 90 elbow
3
x
5
=
15
2) 45 elbow x 2.5 = 0
3) IPEX Low Profile Termination x 5 = 0
4) IPEX 4" Concentric Termination x
20
=
0
5) IPEX 3" Concentric Termination x 20 = 0
6)
3" Tee Termination
x 5 = 0
7)
4" Tee Termination
x
5
=
0
8) 3" Snorkel Termination 1 x 15 = 15
9) 4" Snorkel Termination x
15
=
0
10) Length of Straight Section in feet NA 40 = 40
Total (add up lines
1 through 10)
70
Equivalent Vent Length Calculation Sheet
Maximum equivalent vent lengths are specific to the fuel
type of the water heater. It is imperative when performing
vent calculations the following be taken into consideration:
ATTENTION