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Specifications
Vent Tables
(Intake Only)
Model Number
Max Intake Vent Length (feet) 3" Max Intake Vent Length (feet) 4"
UCG100H399 25
50
UCG80H399 25
50
WARNING!
The UCG(80,100)H399 model is not approved for 2 inch diameter vent pipe. Venting with 2 inch pipe may
result in damage to the water heater or cause an unsafe condition.
DO NOT
use 2 inch Vent Air Intake Pipe!
Determining required intake vent length
1. Determine the total length of straight vent pipe (in feet) required for the intake.
2. Add 5 feet of venting for every 90° elbow.
3. Add 2 ½ feet of venting for every 45° elbow.
4.
Total vent length cannot exceed “Max Intake Vent Length” on the venting table shown above.
Example of Total Intake Vent Length for UCG100H399 installation:
A 3” venting system has a total of two 90-degree elbows and a total straight pipe length of 10 feet.
Equivalent vent length for elbows: 2 x 5 feet = 10 feet.
Total equivalent vent distance = 10 feet + 10 feet = 20 feet total equivalent vent length. This is below
the maximum allowed distance of 25 feet for this model using 3” vent.
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