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MFC Series Boiler Vent and Combustion Air Guide
horizontal run, 20 feet of vertical run
2) A rain cap termination
3) A 10-inch diameter ducted combustion air duct with two 90° elbows and 50 feet of run
MFC Series Pressure Drop Calculation
10-INCH DIAMETER EXHAUST VENT PRESSURE
Two 90° elbows:
One 45° elbow:
95 feet total run (75 horizontal + 20 vertical):
Rain cap exit loss:
Vent drop subtotal:
Altitude correction:
Natural draft for 20 feet @ 20°F outside temperature:
Altitude correction: - 12.6 x 0.982 CF= - 12.37 ft.
TOTAL VENT DROP:
10-INCH DIAMETER COMBUSTION AIR DUCT PRESSURE
Two 90 elbows:
50 feet total run:
Entrance loss: 1 x 4.46
Combustion air drop subtotal:
Altitude correction:
COMBUSTION AIR DROP TOTAL: =
SYSTEM TOTAL PRESSURE DROP
Vent drop + combustion air duct pressure drop:
FINAL PRESSURE DROP TOTAL: =
Pressure drop is less than 140 equivalent feet = SYSTEM OK.
TAG-0080_OG • GF-148-V •
2 x 2.68
= 5.36 ft.
1 x 2.05
= 2.05 ft.
95 x 0.4
= 38.00 ft.
1 x 8.81
= 8.81 ft.
= 54.22 ft.
54.22
= 55.21 ft.
0.982 (CF)
= 12.6 ft.
42.84 ft.
=
2 x 1.88 = 3.76 ft.
50 x 0.3 = 15.00 ft.
= 4.46 ft.
= 23.22 ft.
= 32.22
= 23.65 ft.
0.982 CF
23.65 ft
= 42.84 + 23.65
66.49 ft.
CONCLUSION:
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3/29/2023
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