Installation Guide

Pomona, CA Clemmons, NC Nashville, TN
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USE ONLY HAYWARD GENUINE REPLACEMENT PARTS
14
(A) ALL AIR SUPPLY FROM INSIDE THE BUILDING:
The conned space shall be provided with 2 permanent openings communicating directly with an addi-
tional room(s) of sufcient volume so that the combined volume of all spaces meets the criteria for an un-
conned space (a space whose volume is not less than 50 cubic feet per 1,000 btu/hr). The total input of all
gas utilization equipment installed in the combined space shall be considered in making the determination.
Each opening shall have a minimum free area of 1 square inch per 1,000 btu/hr of the total input rating of all
gas utilization equipment in the conned space, but not less
than 100 square inches. See Table 5. One opening shall be
within 12 inches of the top and and one within 12 inches of
the bottom of the enclosure.
(B) ALL AIR SUPPLY FROM OUTDOORS:
The conned space shall be provided with 2 permanent
openings, once commencing within 12 inches of the bottom
of the enclosure. The opening shall communicate directly,
or by ducts, with the outdoors or spaces (crawl or attic) that
freely communicate with the outdoors.
1. When communicating with the outdoors (either directly or
through vertical ducts), each opening shall have a minimum free
area of 1 square inch per 4,000 btu/hr of total input rating of all
equipment in the enclosure. See Table 5.
2. When communicating with the outdoors through horizontal
ducts, each opening shall have a minimum free area of 1 square
inch per 2,000 btu/hr of total input rating of all equipment in the
enclosure. See Table 5.
3. When ducts are used, they shall be of the
same cross-sectional area as the free area
of the openings to which they connect.
The minimum dimension of rectangular air
ducts shall not be less than 3 inches.
4. When installing a heater below ground (in
a pit), combustion and ventilation air open-
ings must be provided as shown in Figure
4. Each opening shall have a minimum free
area of 1 square inch per 250 btu/hr or total
input rating of all equipment in the pit.
See Table 5. Below-ground (pit) installa-
tions must be natural gas only.
For more detailed methods of providing
air for combustion and ventilation, refer to
the latest edition of the National Fuel Gas
Code (ANSI Z223.1/NFPA 54).
Table 5: Combustion and Ventilation Air Requirements
Free Area per Btu
Requirement
Total Input
(btu/hr)
Combustion Air Free
Area Required (sq. in.)
Ventilation Air Free
Area Required (sq. in.)
1 sq. in. per 1,000 btu/hr
(paragraph A)
150,000 150 150
200,000 200 200
250,000 250 250
300,000 300 300
350,000 350 350
400,000 400 400
500,000 500 500
1 sq. in. per 2,000 btu/hr
(paragraph B-2)
150,000 75 75
200,000 100 100
250,000 125 125
300,000 150 150
350,000 175 175
400,000 200 200
500,000 250 250
1 sq. in. per 4,000 btu/hr
(paragraph B-1)
150,000 37.5 37.5
200,000 50 50
250,000 62.5 62.5
300,000 75 75
350,000 87.5 87.5
400,000 100 100
500,000 125 125
1 sq. in. per 250 btu/hr
(paragraph B-4)
150,000 600 600
200,000 800 800
250,000 1000 1000
300,000 1200 1200
350,000 1400 1400
400,000 1600 1600
500,000 2000 2000
Figure 4
Below-Ground (Pit) Installation
Figure 9
Below-Ground (Pit) Installation
Ground Level
Ventilation
Air
Combustion
Air
Air Duct from
Ground to Base
Drip Tee
Gas Cock
Sediment Trap
Level Flooring
or Slab
Rise of 1 inch
per foot
Vent Cap