Lochinvar GAS HEATER FOR COMMERICAL POOL APPLICATIONS - Manual (Page 11)

Figure 12 – Vent Termination from Flat Roof 10' or Less
from Parapet Wall
Figure 13 – Vent Termination from Flat Roof More Than 10'
from Parapet Wall
Sidewall Vent Termination Clearances
and Location
Locate the bottom of the vent terminal at least 12 inches
(30cm) above grade and above normal snow levels. Locate the
bottom of the vent terminal at least 7 feet (2.13m) above grade
when located adjacent to public walkways. Do not terminate
directly above a public walkway.
Do not terminate the venting system in a window well,
stairwell, alcove, courtyard, or other recessed area. Do not
terminate the venting system below grade.
Locate vent termination at least 3 feet (0.91m) from an inside
corner of an L-shaped structure.
Provide a minimum clearance of 4 feet (1.2m) horizontally
from electric meters, gas meters, regulators, and relief
equipment. Never locate the vent cap above or below electric
meters, gas meters, regulators, and relief equipment unless a
4 foot (1.2m) horizontal clearance is maintained.
Terminate the venting system at least 3 feet (0.9m) above any
forced air inlet within 10 feet (3.05m).
Terminate the venting system at least 4 feet (1.2m) below,
4 feet (1.2m) beside, or 1 foot (30cm) above any door, window,
or gravity air inlet into any building.
Locate vent termination at least 8 feet (2.4m) horizontally from
any combustion air intake located above the sidewall
termination cap.
ƽ
CAUTION: Pool heaters which are shut
down or will not operate may experience freezing
due to convective air flow in the flue pipe,
through the air inlet, or from negative pressure in
the mechanical room. In cold climates, operate
pump continuously to help prevent freezing of
pool heater water. Provide proper freeze
protection. See Freeze Protection, page 7.
TABLE–A
Input Flue Air Inlet
Btu/hr Size Size*
500,000 6" 6"
650,000 8" 8"
750,000 8" 8"
990,000 10" 10"
1,260,000 12" 12"
1,440,000 12" 12"
1,800,000 14" 12"
2,070,000 14" 12"
* Minimum diameter for air inlet pipe. Installer may increase diameter one
pipe size for ease of installation, if needed. Refer to the National Fuel Gas
Code (ANSI Z223.1) Vent Tables for additional guidance on vent sizing of fan
assisted appliances.
Installation and Service Manual
11
TABLE - B
Flue and Air Inlet Pipe Sizes