Carrier PG95ESU User Manual page 39

PG95ESU: Installation, Start-up, Operating and Service Maintenance Instructions
Venting System Length Calculations
The Total Equivalent Vent Length (TEVL) for EACH combustion air or vent pipe equals the length of the venting system, plus the equivalent length of
elbows used in the venting system
Standard vent terminations or factory accessory concentric vent terminations count for zero deduction.
See vent system manufacturer's data for equivalent lengths of flexible vent pipe or other termination systems. DO NOT ASSUME that one foot of
flexible vent pipe equals one foot of straight PVC/ABS DWV vent pipe.
Compare the Total Equivalent Vent Length to the Maximum Equivalent Vent Lengths
Example 1
A direct-vent 60,000 BTUH furnace installed at 2100 ft. (640M). Venting system includes FOR EACH PIPE:
70 feet (22 M) of vent pipe, 65 feet (20 M) of combustion air inlet pipe, (3) 90º long-radius elbows, (2) 45º long-radius elbows, and a factory accessory
concentric vent kit.
Can this application use 2" (50 mm ND) PVC/ABS DWV vent piping?
Measure the required linear length of air inlet and vent pipe;
insert the longest of the two here
Add equiv length of (3) 90º long-radius elbows
(use the highest number of elbows for either the vent or inlet
pipe)
Add equiv length of (2) 45º long-radius elbows
(use the highest number of elbows for either the vent or inlet
pipe)
Add equiv length of factory concentric vent term
Add correction for flexible vent pipe, if any
Total Equivalent Vent Length (TEVL)
Maximum Equivalent Vent Length (MEVL)
Is TEVL less than MEVL?
Example 2
A direct-vent 60,000 BTUH furnace installed at 2100 ft. (640M). Venting system includes FOR EACH PIPE:
100 feet (30 M) of vent pipe, 95 feet (29 M) of combustion air inlet pipe, (3) 90º long-radius elbows, and a polypropylene concentric vent kit. Also
includes 20 feet (6.1 M) of flexible polypropylene vent pipe, included within the 100 feet (30 M) of vent pipe.
VERIFY FROM POLYPROPYLENE VENT MANUFACTURER'S INSTRUCTIONS for the multiplier correction for flexible vent pipe.
Can this application use 60mm o.d. (2") polypropylene vent piping? If not, what size piping can be used?
Measure the required linear length of RIGID air inlet and vent pipe; insert the
longest of the two here: 100 ft. Of rigid pipe - 20 ft. Of flexible pipe
Add equiv length of (3) 90º long-radius elbows (use the
highest number of elbows for either the vent or inlet pipe)
Add equiv length of 45º long-radius elbows
(use the highest number of elbows for either the vent or
inlet pipe)
Add equiv length of factory concentric vent term
Add correction for flexible vent pipe, if any
* VERIFY FROM VENT MANUFACTURER'S INSTRUCTIONS; For example only, assume 1 meter of flexible 60mm (2") or 80mm (3") polypropylene
pipe equals 2.0 meters (6.5 ft.) of PVC/ABS pipe.
Total Equivalent Vent Length (TEVL)
Maximum Equivalent Vent Length (MEVL)
Is TEVL less than MEVL?
Maximum Equivalent Vent Length (MEVL)
Is TEVL less than MEVL?
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
(Table 19).
3
0
9
2*
(Table 18).
(22 M)
3 ft.
3 x =
(0.9 M) (2.7 M)
1.5 ft.
2 x =
(0.5 M) (0.9 M)
(25 M)
(29 M)
80 ft.
=
(24 M)
5 ft. 15 ft.
x =
(1.5 M) (4.6 M)
0 ft.
x =
(0 M)
3.3 ft 30 ft.
x =
(0.9 M) (9 M)
20 ft. 40 ft.
x =
(6.1 M) (12.2 M)
165 ft.
(50 M)
95 ft.
(29 M)
NO
185 ft.
(57 M)
YES
39
70 ft. Use length of the longer of the vent
or air inlet piping system
9 ft.
From Table 19
3 ft.
From Table 19
0 ft. From Table 19
From Vent Manufacturer's
0 ft.
instructions; zero for PVC/ABS DWV
82 ft.
Add all of the above lines
95 ft.
For 2" pipe from Table 18
YES Therefore, 2" pipe MAY be used
Use length of the longer of the vent
or air inlet piping system
Example from polypropylene vent manufacturer's
instructions, Verify from vent manufacturer's
instructions.
Add all of the above lines
For 2" pipe from Table 18
Therefore, 60mm (2") pipe may NOT be used; try
80mm (3")
For 3" pipe from Table 18
Therefore, 80mm (3") pipe MAY be used