Mechanical Code…
- Vented Appliance Category 1
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An appliance that operates with a non-positive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent.
- Vented Appliance Category 2
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An appliance that operates with a non-positive vent static pressure and with a vent gas temperature that may cause excessive condensate production in the vent.
- Vented Appliance Category 3
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An appliance that operates with a positive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent.
- Vented Appliance Category 4
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An appliance that operates with a positive vent static pressure and with a vent gas temperature that may cause excessive condensate production in the vent.
(Uniform Mechanical Code® 224.0)