Exhaust Vent And Intake Pipe Sizing; Longer Vent Runs - Westinghouse WGR050NG076 Installation Instructions Manual

The building owner is responsible for keeping the exhaust and intake terminations free of snow, ice, or other potential blockages, as
well as scheduling routine maintenance. Failure to keep the vent piping terminations clear and properly maintain the heater could result
in property damage, severe personal injury, or death.
For each floor containing bedroom(s), a carbon monoxide detector and alarm shall be placed in the living area outside the bedrooms,
as well as in the room that houses the heater. Detectors and alarms shall comply with NFPA 720 (latest edition). Failure to comply with
requirements for detectors and alarms could result in property damage, severe personal injury, or death.
E. EXHAUST VENT AND INTAKE PIPE SIZING
1. The exhaust vent and intake pipe size is 2".
2. The total equivalent length of exhaust vent and intake pipe should not exceed 150 feet.
a. The equivalent length of elbows, tees, and other fittings are listed in the Friction Loss Table, Table 5:
FITTINGS OR PIPING
90 DEGREE ELBOW*
45 DEGREE ELBOW
COUPLING
AIR INLET TEE
STRAIGHT PIPE
CONCENTRIC VENT KIT
V500 2" VENT KIT
V1000 3" VENT KIT
V2000 4" VENT KIT
Table 5 - *Friction loss for long radius elbow is 1 foot less. NOTE: Consult Polypropylene venting instructions for friction loss and pressure
drop equivalents.
b. For example: If the exhaust vent has two 90° elbows and 10 feet of PVC pipe we will calculate:
Exhaust Vent Equivalent Length = (2x5) + 10 = 20 feet.
Further, if the intake pipe has two 90° elbows, one 45° elbow and 10 feet of PVC pipe, the following calculation applies:
Intake Pipe Equivalent Length = (2x5) + 3 + 10 = 23 feet.
Finally, if a concentric vent kit is used we find:
Total Equivalent Length = 20 + 23 + 3 = 46 feet.
The total equivalent length is 46 feet which is well below the maximum of 150 feet.
c. The exhaust vent and intake pipe are intended to penetrate the same wall or roof of the building.
d. Effort should be made to keep a minimum difference in equivalent length between the exhaust vent and intake pipe.
3. The minimum total equivalent length is 16 feet.
F. LONGER VENT RUNS
1. The maximum total equivalent length can be extended by increasing the diameter of both the exhaust vent and intake pipes.
However, the transitions should begin a minimum of 15 equivalent feet from the water heater.
a. The maximum total equivalent length for increased diameter vent pipes is 200 feet.
b. Transitions should always be made in vertical sections of pipe to prevent the condensate from pooling in the vent pipe.
VENT CONNECTION
2"
Table 6 – Vent Run Transition
c. Transition from 2" to 3" pipe should be made at the water heater.
Do not exceed the maximum lengths for vent pipes. Excessive length could result in appliance shutdown and property damage.
FRICTION LOSS EQUIVALENT IN PIPING AND FITTINGS
REDUCING COUPLING
3" X 2"
EQUIVALENT FEET
2"
5'
3'
0'
0'
1'
3'
1'
N/A
N/A
3"
5'
3'
0'
0'
1'
3'
N/A
1'
1'
VENT TRANSITION
3"
WHL-001 REV. 9.3.14
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