User Guide

ManualsBrandsField Controls ManualsBoiler VentingPressure Switch for PVG-100

page 3 of 12

POWER VENTER SIZING

In order to choose the correct size power venter for a particular installation, the total input  ring 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 di erence.

MAXIMUM EQUIVALENT HORIZONTAL PIPE LENGTH (FEET)

BTU/HR INPUT

VENTER MODEL NUMBER AND VENT PIPE DIAMETER

PVG-100 PVG-300 PVG-600

3" 4" 4" 5" 6" 5" 6" 8"

25,000 270 455 -- -- -- -- -- --

55,000 100 169 -- -- -- -- -- --

70,000 -- 144 -- -- -- -- -- --

100,000 -- 100 305 -- -- -- -- --

145,000 -- -- 145 247 334 413 -- --

220,000 -- -- 64 100 147 181 -- --

310,000 -- -- -- 54 74 91 146 216

400,000 -- -- -- -- -- 54 87 134

520,000 -- -- -- -- -- -- 52 86

610,000 -- -- -- -- -- -- -- 66

Table 2

PROCEDURE FOR CALCULATING TOTAL EQUIVALENT PIPE LENGTH IN FEET

1. Calculate the total equivalent feet for each type of  tting used in the venting system from the following chart.

2. Calculate the total amount of feet for the straight lengths of vent pipe.

3. Add the equivalent feet for the  ttings with the total amount of feet of straight lengths.

Table 3

*Reducer or increaser ratio (d/D) small diameter divided by the larger diameter. (See Figure 3)

Example: 4" to 8" reducer, the reducer ratio is d/D =

⁄8 =

⁄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

⁄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

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 1925313844505663

90° ELBOW 5 7 9 11 12 14 16 18

45° ELBOW 34456789

REDUCER

(d/D)*

⁄4 8 11141719222528

⁄2 5 7 8 1012131517

⁄4 23344566

P/N 46246300 Rev M 04/20