State Industries STC-074 specifications Make-Up Air Vertical Ducts, Make-Up Air Horizontal Ducts

SBN TANK TYPE COMMERCIAL GAS WATER HEATER

SERVICE HANDBOOK

Often, it is more practical to install vertical make-up ducts to the outdoors.

Make-Up Air - Vertical Ducts

Again, two openings are required: one within 12 inches of the top of the enclosure and one within twelve inches of the bottom of the enclosure. Each opening must have a free area of not less than 1 square inch per 4,000 BTUH of the total input of all appliances within the enclosure.

Make-Up Air - Horizontal Ducts

When the heater is installed in an interior room with no roof access for vertical ducts, horizontal make-up air ducts should be installed. When using horizontal ducts, two openings are required - one within 12 inches of the top of the enclosure and one within 12 inches of the bottom of the enclosure. Each opening must have a free area of not less than 1 square inch per 2,000 BTUH of the total input of all appliances within the enclosure.

©2003 8 Technical Training Department

Ashland City, Tennessee