Longer Vent Runs - Pioneer PHR100-55 Instruction Manual

a. The equivalent length of elbows, tees, and other fittings are listed in the Friction Loss Table
below:
FRICTION LOSS EQUIVALENT IN PIPING AND FITTINGS
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 4 - *Friction loss for long radius elbow is 1 foot less.
b. For example: If the exhaust vent has two 90° elbows and 10 feet of PVC pipe we will calculate:
Exhaust Vent Pipe Equivalent Length = (2x5)+10=20 feet.
Further, if the intake air vent pipe has two 90° elbows, one 45° elbow and 10 feet of PVC pipe,
the following calculation applies:
Intake Air Vent Pipe Equivalent Length = (2x5)+3+10=23 feet.
Finally, if a concentric vent kit is used we find:
Total Combined Equivalent Length = 20+23+3=46 feet.
Therefore, the total combined equivalent length is 46 feet which is well below the maximum of 85
feet.
c. The intake air vent pipe and the exhaust vent 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 intake
air vent pipe and the exhaust vent.
3. The minimum combined equivalent length is 16 equivalent feet.
E. LONGER VENT RUNS
1. The maximum combined equivalent length can be extended by increasing the diameter of both exhaust
vent and intake air vent pipe equally. However, the transitions should begin a minimum of 15 equivalent
feet from the water heater.
a. The maximum equivalent length for increased diameter vent pipes is 125 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"
3"
Table 5 – Vent Run Transition
c. If the transition occurs at a distance greater than 15 equivalent feet from the water heater, the
maximum equivalent length will be reduced.
EQUIVALENT FEET
2"
5'
3'
0'
0'
1'
3'
1'
N/A
N/A
REDUCING COUPLING
3" X 2"
4" X 3"
3"
5'
3'
0'
0'
1'
3'
N/A
1'
1'
VENT TRANSITION
29
4"
3'
1'
0'
0'
1'
N/A
N/A
1'
1'
3"
4"