Instructions / Assembly

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Example:4"to8"reducer,thereducerratioisd/D=
4
⁄8=
1
⁄2. To estimate the equivalent foot length for
thetting,usethesmallerpipediameterfortheequivalentlengthgure.Example:4"to8"reducer;the
reducer ratio is
1
⁄2andthesmallerpipediameteris4".So,fromthechart,theequivalentfeetwouldbe
7 feet.
Example:SystemPipeSize=4"
Step1 2–90°Elbows(4")=14Ft.
Step2 10-2Ft.Lengthsof4"Pipe=20Ft.
Step3 TotalEquivalentFeet=14Ft.+20Ft.=34Ft.
Figure 3
POWER VENTER SIZING
In order to choose the correct size power venter for a particular installation, the total input firing rate and
total equivalent length of vent pipe to be used must be known. Refer to Table 2 to determine the maximum
allowableequivalentfeetofpipeforeachmodelusedwiththepipediametersshown.Whenventingmultiple
appliances, add the input of each appliance to determine the total input. Always choose a power venter that
is capable of handling more than the system requires. The choke plate can be adjusted to compensate for
the difference.
MAXIMUM EQUIVALENT HORIZONTAL PIPE LENGTH (FEET)
BTU/HR INPUT
VENTER MODEL NO. AND VENT PIPE DIAMETER
PVO-300 PVO-600
4" 5" 6" 5" 6" 8"
0.75 287 --- --- --- --- ---
1.00 150 257 346 428 --- ---
1.50 75 120 172 212 --- ---
2.25 --- 51 70 86 143 211
3.00 --- --- --- 46 74 116
3.75 --- --- --- --- 51 84
4.00 --- --- --- --- --- 77
Table 2
PROCEDURE FOR CALCULATING TOTAL EQUIVALENT PIPE LENGTH IN FEET
Calculate the total equivalent feet for each type of fitting used in the venting system from the 1.
following chart.
Calculate the total amount of feet for the straight lengths of vent pipe.2.
Add the equivalent feet for the fittings with the total amount of feet of straight lengths.3.
EQUIVALENT LENGTH (FEET) OF VENT PIPE FOR VENT PIPE FITTINGS
VENT PIPE FITTINGS
VENT PIPE DIAMETER
3" 4" 5" 6" 7" 8" 9" 10"
TEE 19 25 31 38 44 50 56 63
90º ELBOW 5 7 9 11 12 14 16 18
45º ELBOW 3 4 4 5 6 7 8 9
REDUCER
(d/D)*
1/4 8 11 14 17 19 22 25 28
1/2 5 7 8 10 12 13 15 17
3/4 2 3 3 4 4 5 6 6
Table 3
*Reducerorincreaserratio(d/D)smalldiameterdividedbythelargerdiameter.(SeeFigure3)