268882-UIM-A-0407
12
Unitary Products Group
3.
Three vent terminal elbows (two for the vent and one for the com-
bustion air intake) are already accounted for and need not be
included in the equivalent length calculation.
4.
All combustion air and vent pipe must conform to American
National Standards Institute (ANSI) and American Society for Test-
ing and Materials (ASTM) standards D1785 (Schedule 40 PVC),
D2665 (PVC-DWV), F891 (PVC-DWV Cellular Core), D2261
(ABS-DWV) or F628 (Schedule 40 ABS). Pipe cement and primer
must conform to ASTM Standard D2546 (PVC) or D2235 (ABS). If
ABS pipe is to be used, any joint where ABS pipe is joined to PVC
pipe must be glued with cement that is approved for use with
BOTH materials. Metallic materials must not be used for venting or
air intake.
5.
If a flexible connector is used in the vent system, it must be made
of a material that is resistant to acidic exposure and to at least
225° F temperature. Flexible connectors are also allowed in the
combustion air pipe.
6.
All models are supplied with 2" vent connections. When the pipe
must be increased to 3" diameter, the transition from 2" to 3" must
be done as close to the furnace as possible. For upflow models,
the transition from 2" to 3" should be done immediately above the
furnace. For downflow or horizontal models, the transition from 2"
to 3" pipe should be done immediately after the drain tee or drain
elbow.
7.
In Canada, vents shall be certified to ULC S636, Standard for Type
BH Gas Venting Systems. IPEX System 636 PVC is certified to
this standard.
8.
In Canada, the first three feet (900 mm) of the vent must be readily
accessible for inspection.
Example:
An 80,000 BTUH furnace requires 32 feet of pipe and four 90º elbows.
Using 2" pipe and standard elbows, the total equivalent length will be:
This exceeds the 65 foot maximum equivalent length of 2" pipe allowed
for that model and is thus not acceptable.
By using sweep elbows, the total equivalent length will be:
This is less than the 65 foot maximum equivalent length of 2" pipe
allowed for that model and is thus acceptable.
Alternatively, using 3" pipe and standard elbows, the total equivalent
length will be:
This is less than the 90 foot maximum equivalent length of 3" pipe
allowed for that model and is thus acceptable.
Dimensions are those required in Standard ASTM D-3311.
NOTE:
Sidewall vent terminal may be used for sidewall vent termina-
tions. Refer to part list in the back of the USERS INFORMATION AND
SERVICE AND MAINTENANCE MANUAL for the terminal part number.
*. Vent pipe size must be increased to 3” diameter after connection to furnace
on this model.
IMPORTANT:
Accessory concentric vent / intake termination kits
1CT0302 and 1CT0303 are available and approved for use with these
furnaces.
IMPORTANT:
Furnace vent pipe connections are sized for 2” (5.1 cm).
pipe. Any pipe size change must be made outside the furnace casing in
a vertical pipe section to allow proper drainage of condensate. An offset
using two 45º (degree) elbows will be required for plenum clearance
when the vent is increased to 3” (7.6 cm).
TABLE 4:
Maximum Equivalent Pipe Length
Model Input
BTUH (kW)
Pipe Size
Inches (cm)
Maximum
Equivalent
length feet (m)
60,000
(17.6)
2
(5.1)
65
(19.8)
60,000
(17.6)
3
(7.6)
90
(27.4)
80,000
(23.4)
2
(5.1)
65
(19.8)
80,000
(23.4)
3
(7.6)
90
(27.4)
100,000
(29.3)
2
(5.1)
30
(9.2)
100,000
(29.3)
3
(7.6)
90
(27.4)
TABLE 5:
Equivalent Length of Fittings
Fitting
Equivalent Length
2" 90º sweep elbow
5 feet of 2" pipe
2" 45º sweep elbow
2-1/2 feet of 2" pipe
2" 90º standard elbow
10 feet of 2" pipe
2" 45º standard elbow
5 feet of 2" pipe
3" 90º sweep elbow
5 feet of 3" pipe
3" 45º sweep elbow
2-1/2 feet of 3" pipe
3" 90º standard elbow
10 feet of 3" pipe
3" 45º standard elbow
5 feet of 3" pipe
2" corrugated connector
10 feet of 2" pipe
3" corrugated connector
10 feet of 3" pipe
32 feet of 2" pipe =
32 equivalent feet
4 - 90º standard 2" elbows = (4x10) =
40 equivalent feet
Total =
72 equivalent feet of 2" pipe
32 feet of 2" pipe =
32 equivalent feet
4 - 90º standard 2" elbows = (4x5) =
20 equivalent feet
Total =
52 equivalent feet of 2" pipe
32 feet of 3" pipe =
32 equivalent feet
4 - 90º standard 2" elbows = (4x5) =
40 equivalent feet
Total =
72 equivalent feet of 3" pipe
FIGURE 14:
Dimensions
TABLE 6:
Elbow Dimensions
Elbow
"A" Dimension
2" Standard
2-5/16"
3" Standard
3-1/16"
2" Sweep
3-1/4"
3" Sweep
4-1/16"
TABLE 7:
Combustion Air Intake and Vent Connection Size at Furnace
(All Models)
FURNACE VENT CONNECTION SIZES
Furnace Input
60 - 100 MBH (18.0 - 29.0 kW)
Intake Pipe Size
2” (5.08 cm)
Vent Pipe Size
2” (5.08 cm)
A
A
A
A
STANDARD ELBOW
LONG (SWEEP) ELBOW
