SECTION J: VENTING CONNECTIONS
GENERAL
CAUTION: Proper installation of flue exhaust venting is critical for the safe and efficient operation of the heater.
Definition of Appliance Categories
Heaters are divided into four categories based on the pressure produced in the exhaust and the likelihood of condensate
production in the vent.
Category I. A heater which operates with a non-positive vent static pressure and with a vent gas tempera
ture that avoids excessive condensate production in the vent.
Category II. A heater which operates with a non-positive vent static pressure and with a vent gas tempera
ture that may cause excessive condensate production in the vent.
Category III. A heater which operates with a positive vent pressure and with a vent gas temperature that
avoids excessive condensate production in the vent.
Category IV. A heater which operates with a positive vent pressure and with a vent gas temperature that
may cause excessive condensate production in the vent.
See Table J-1 for appliance category requirements for the Hi Delta.
Note: For additional information on appliance categorization, see appropriate ANSI Z21 Standard and the latest
NFGC or in Canada, the B149 Installation Code or applicable provisions of local building codes.
Determination of Appliance Category for Venting Purposes and Venting Arrangements
WARNING: Contact the manufacturer of the vent material if there is any question about the appliance categoriza-
tion and suitability of a vent material for application on a Category III or IV vent system. Using
improper venting materials can result in personal injury, death or property damage.
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