Installation, Operation & Maintenance Manual Bosch 96% AFUE Gas Furnace | 27
Bosch Thermotechnology Corp. | 04.2019
Data subject to change
7. In Canada, vents shall be certifi ed to ULC S636, Standard for Type BH Gas
Venting Systems. IPEX System 636 PVC is certifi ed to this standard.
8. In Canada, the fi rst three feet (900 mm) of the vent must be readily
accessible for inspection.
9. Minimum vent length for all models is 5 feet.
For single pipe systems it is recommended to install the combustion
air coupling provided and install approximately 18” of PVC pipe on the
furnace.In addition to the vent/fl ue pipe, a single 90° elbow should be
secured to the combustion air intake to prevent inadvertent blockage.
Model Input - kBTU/H (kW) Pipe Size - Inches (cm)
Maximum Equivalent
Length - Feet (m)
60 (17.6) 2 (5.1) 60 (18.2)
60 (17.6) 3 (7.6) 90 (27.4)
80 (23.4) 2 (5.1) 60 (18.2)
80 (23.4) 3 (7.6) 90 (27.4)
100 (29.3) 2 (5.1) 30 (9.1)
100 (29.3) 3 (7.6) 90 (27.4)
120 (35.1) 2 (5.1) N/A
120 (35.1) 3 (7.6) 90 (27.4)
Table 5 Maximum Equivalent Pipe Length
Figure 22
A
A
A
A
STANDARD ELBOW
LONG (SWEEP) ELBOW
Elbow "A" Dimension
2" Standard 2-5/16"
3" Standard 3-1/16"
2" Sweep 3-1/4"
3" Sweep 4-1/16"
Table 6 Elbow Dimensions
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
Table 7 Equivalent Length of Fittings
Example:
An 80,000 BTUH furnace requires 32 feet of pipe and four 90º elbows. Using 2"
pipe and standard elbows, t he total equivalent length will be:
32 feet of 2" pipe = 32 equivalent feet
4 - 90º standard 2" elbows = (4x10) = 40 equivalent feet
Total = 72 equivalent feet of 2" pipe
This exceeds the 65 foot maximum equi valent length of 2" pipe allowed for that
model and is thus not acceptable.
By using sweep elbows, the total equivalent length will be:
32 feet of 2" pipe = 32 equivalent feet
4 - 90º sweep 3" elbows = (4x5) = 20 equivalent feet
Total = 52 equivalent feet of 2" pipe
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:
32 feet of 3" pipe = 32 equivalent feet
4 - 90º standard 2" elbows = (4x10))= 40 equivalent feet
Total = 72 equivalent feet of 3" pipe
This is less than the 90 foot maximum equivalent length of 3" pipe allowed for that
model and is thus acceptable.
Connection Type Size - Inches (cm)
Intake Pipe 2" (5.1)
Vent Pipe 2" (5.1)
Table 8 Combustion Air Intake & Vent Connection Size (All Models)
Furnace vent pipe connections are sized for 2” (5.1 cm). pipe. Any pipe
size change must be made outside the furnace cabinet in a vertical pipe
section to allow proper drainage of condensate. An off set using two 45º
(degree) elbows will be required for plenum clearance when the vent is
increased to 3” (7.6 cm).
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