SBN71-120 thru 85-390, SBD30-150/199 TANK TYPE COMMERCIAL
GAS WATER HEATER SERVICE HANDBOOK
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9.
Obstructions can cause down drafts. The vent pipe should be extended to meet local
codes.
9 RULES FOR GOOD VENTING
7.
Horizontal elements should be limited
to 75% of the vertical rise of the vent above
the connection.
8.
Flue gases must be kept hot for proper
venting. Single wall vent exposed to cold air
may not vent properly.
HORIZONTAL
ELEMENTS
LIMITED TO
75% OF
TOTAL
VERTICAL
HEIGHT
VENT RUNS
BEYOND EXTERIOR
WALLS OR INTO
UNHEATED AREAS
SHOULD BE
DOUBLE WALL.
