PVI Industries PV500-45U - Manual (Page 20)

20
PV500-45U 06/12
The following vent information is provided for use in design calculations, if needed.
Venting Specifications
Input MBtu
Combustion Air
Volume (cfm)
Max Vent
Press. ”W.C.
399 136 0.5
500 170 0.6
750 255 1.0
900 306 1.2
1000 340 1.3
9.3 Vertical or Horizontal Vent Termination:
1. The vent terminal must have a minimum clearance of 4 feet (1.22 m) horizontally from, and in no case be
located above or below, unless a 4 foot (1.22 m) horizontal distance is maintained from electric meters, gas
meters, regulators and relief equipment.
2. The vent cap must terminate at least 3 feet (0.91 m) above any forced air inlet within 10 feet (3.05 m).
3. The vent shall terminate at least 4 feet (1.22 m) below, 4 feet (1.22 m) horizontally from or 1 foot (0.3 m) above
any door, window or building air inlet to the building.
4. The vent system shall terminate at least 1 foot (0.3 m) above grade and at least 1 foot (0.3m) above possible
snow accumulation levels and shall terminate at least 7 feet (2.13 m) above grade when located adjacent to
public walkways or gathering areas.
5. To avoid a blocked flue condition, keep the vent cap clear of snow, ice, leaves, debris, etc.
6. The vent must not exit over a public walkway, near soffit vents or crawl space vents or other areas where
condensate or vapor could create a nuisance or hazard or cause property or could be detrimental to the
operation of regulators, relief valves or other equipment.
7. A horizontal vent must extend one foot beyond the wall.
8. A horizontal vent terminal must not be installed closer than 3 feet (0.91m) from an inside corner of an L-shaped
structure.
9. A vertical vent must exhaust outside the building at least 3 feet (0.91m) above the point of the exit and at least 2
feet (0.61 m) above the highest point of the roof within a 10-foot (3.05 m) radius of the termination.
10. A vertical termination less than 10 feet (0.91 m) from a parapet wall must be a minimum of 2 feet (0.61 m)
higher than the parapet wall.
9.4 Combining
Category IV Vents
Combined TRICON Category IV gas vent systems must incorporate an Exhausto or Tjernlund variable speed,
modulating, mechanical draft inducer capable of maintaining the appropriate negative draft at the end of the common
flue, to assure that all water heaters in the combined vent system operate with a negative draft. Do not exceed
negative 0.25” W.C.
See “Combining Vents with a Draft Inducer” illustration below.
Vent Fitting Equivalent Length
Vent Pipe: 6” Vent 7” Vent 8” Vent 9” Vent
90º Elbow 8 feet 9 feet 10 feet 11 feet
90º Long Radius Elbow 5 feet 5 feet 5 feet 6 feet
45º Elbow 5 feet 5 feet 5 feet 5 feet