27
Maximum Vent Length:
Direct Vent Maximum Vent Length (Combined Maximum Length for Intake and Exhaust)
Model
Number
Max Vent Length in
feet (meters) for 2
inch (5.1 cm)
Max Vent Length in
feet (meters) for 3
inch (7.6 cm)
Max Vent Length in
feet (meters) for 4
inch (10.2 cm)
EFR60T120 60 (18) 120 (36) 170 (51)
Table 3
Note: The venting distance shown in the chart above is the combined maximum distance for the intake and
exhaust pipe and elbows. The intake and exhaust vent terminals may be in different locations (i.e., different
walls or one wall, one roof) provided the intake equivalent venting distance does not exceed the exhaust by
more than 30 feet (9 m).
Determining required vent length:
1. Determine the total length of straight vent pipe (in feet) required for both the intake and the exhaust.
2. Add 5 feet (1.5 m) of venting for every 90° elbow.
3. Add 2 ½ feet (.7 m) of venting for every 45° elbow.
4. Total vent length cannot exceed “Max Vent Length” in Table 3.
5. Air intake cannot exceed exhaust by more than 30 feet (9 m) in any venting situation.
Example of Total Direct Vent Length for EF100T199:
A 3 inch (7.6 cm) venting system has a total of six 90-degree elbows and a total straight pipe length of 65 feet (19.5
m) (includes both intake and exhaust pipe).
Equivalent vent length for elbows: 6 x 5 feet (1.5 m) = 30 feet (9 m).
Total equivalent vent distance = 65 feet (19.5 m) + 30 feet (9 m) = 95 feet (28.5 m) total equivalent vent
length. This is below the maximum allowed distance of 100 feet (30 m) for this model using 3 inch (7.6 cm)
vent.
NOTICE
Do not include the condensate elbow or vent terminals in determining maximum vent length. POWER VENT INSTALLATION
Power venting is where the indoor air is used and the exhaust is vented to the outside. Venting may be run horizontally
through an outside wall or vertically through a roof through using either 2 inch (5.1 cm), 3 inch (7.6 cm) or 4 inch (10.2
cm) diameter pipe. This water heater is supplied with a 2 inch (5.1 cm) diameter screened intake and exhaust elbow,
referred to as the air intake terminal and the exhaust vent terminal.
Power Vent Terminal Location:
Refer to the “Direct Vent Terminal Location” section previously mentioned to determine the proper exhaust vent
location. Plan the vent system layout so that proper clearances are maintained from plumbing and wiring.
Vent pipes serving power vented appliances are classified by building codes as “vent connectors”. Required
clearances from combustible materials must be provided in accordance with information in this manual under
LOCATION OF WATER HEATER, and CLEARANCES, and with National Fuel Gas Code and local codes.
All vent pipes and terminals are to have a 1” minimum clearance to combustibles. DO NOT use the placement of
insulation or other materials in the required clearance spaces surrounding the venting to combustible material unless
otherwise specified.
Horizontal Installation:
In a horizontal application, it is important that condensate not be allowed to buildup in the exhaust vent pipe. To
prevent this from happening, the pipe should be installed with a slight upward slope of ¼ inch (.6 cm) per foot (.3
m). The vent system must be supported every 5 feet (1.5 m) of vertical run and every 3 feet (.9 m) of horizontal
run of vent pipe length.