Gas Furnaces
VENTED APPLIANCE CATEGORIES
Category I. An appliance that operates with a no positive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent
Category II. An appliance that operates with a no positive vent static pressure and with a vent gas temperature that is capable of causing excessive condensate production in the vent
Category III. An appliance that operates with positive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent
Category IV. An appliance that operates with positive vent static pressure, with a vent gas temperature that is capable of causing excessive condensate production in the vent
Gas Line Requirements:
Appliances
G2419.4 (408.4) Sediment trap
SECTION G2420 SHUTOFF VALVES
APPLIANCE GAS CONNECTIONS
G2422.1 Connecting appliances
G2422.1.1 Protection from damage
G2422.1.2.3 Prohibited locations and penetrations
HVAC General
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M1401.1 |
Installation |
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M1401.2 |
Access |
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M1401.3 |
Equipment and appliance sizing |
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M1401.4 |
Exterior installation |
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M1401.5 |
Flood Hazards |
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SECTION M1307
Appliance Installation General
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M1305.1 |
Clearance and access requirements |
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M1305.1.1 M1402.2 |
Furnaces and air handler clearance |
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M1305.1.2 |
Appliances in rooms |
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M1305.1.3 |
Appliances in attics |
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M1305.1.4 |
Appliances under floors |
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M1305.1.3.1 |
Lighting requirements at appliance |
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M1305.1.4.1 |
Ground clearances |
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M1307.2 |
Appliance anchoring |
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M1306.1 |
Clearance from combustibles |
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M1307.3 |
Elevation from ignition source |
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M1307.3.1 |
Protection from impact |
Return Air Requirements
IMC 601.5 Prohibits return air within 10 ft from combustion appliances.
Combustion Air
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M1701.1 |
Scope |
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M1701.2 |
Opening locations |
Combustion Air and venting and dilution air requirements
Sections G2406 -- G2407 -- G2408
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Prohibited Locations inside appliance locations |
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Combustion air |
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Appliance combustion air |
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Appliance location |
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Draft hood/regulator location |
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Make up air required |
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Indoor combustion air |
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Outdoor combustion air |
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Elevation of ignition source |
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Installation in garages |
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Clearance from grade |
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Clearance from combustibles |
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Clearance reduction allowances |
Gas furnace venting requirements
CO Vent Requirements:
Unless specified, manufacturer’s instructions should be followed. Venting code references are listed below.
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Code Reference |
Description |
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General requirements |
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Installation Requirements |
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Required connectors |
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Shielding from insulation |
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Protection against damage |
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SECTION G2427 |
Venting of appliances |
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Above air handling spaces |
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G2427.4 |
Vent type required for appliance category (I.E. Type 1 or Type 4) |
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G2427.4.1 |
Plastic Vent Pipes |
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Chimney roof terminations |
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Gas vent roof terminations |
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G2427.6.7 |
Exterior wall terminations |
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G2427.6.5 |
Minimum height requirements |
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G2427.7.1-13 |
Single wall vent pipe |
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Vent connector requirements |
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Draft hoods and controls |
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Direct vent and integral vent systems |
