031	AIR CONDITIONING, HEATING, AND VENTILATING: EQUIPMENT, PARTS AND ACCESSORIES (SEE RELATED ITEMS IN CLASS 740)
03103  *	Air Conditioners: Commercial, and Parts and Accessories not Individually Itemized
03104  *	Air Conditioners: Controlled Environment (For Computer Rooms, etc.), and Parts and Accessories not Individually Itemized)
03105  *	Air Conditioners (Cooling and Cooling/Heating Types): Window and Wall Mounted, and Parts and Accessories Not Individually
	Itemized
03106  *	Air Conditioning and Heating: Central Units, and Parts and Accessories Not Individually Itemized
03108  *	Air Doors and Curtains
03109  *	Air Flow Meters
03110  *	Air Purifiers, Accessories and Supplies
03111  *	Blowers: Industrial Types
03113  *	Chillers, Heat Exchangers and Receivers
03115  *	Chilled Water Meter System
03117  *	Coils: Chilled or Heated Water, and Direct Expansion
03118  *	Coil and Fan Units, Air Conditioning
03120  *	Compressors, Air Conditioning: Hermetically Sealed, Window Unit Type
03121  *	Compressors, Air Conditioning: Industrial Type, and Parts
03123  *	Condensing Units (For Air Conditioners)
03125  *	Controls: Limit Switches, Relays, Thermostats, Gas Valves, etc.
03126  *	Control Systems: Complete (For Automatic Temperature Control)
03128  *	Cooling Towers: Forced Air, Gravity, etc.
03130  *	Dehumidifiers and Humidifiers
03132  *	Duct, Prefabricated (Flexible or Rigid): Glass Fiber, Plastic, etc.
03133  *	Duct, Fabricated, Metal
03134  *	Dust Collectors, Industrial Type
03136  *	Electronic Air Cleaners, Electrostatic Precipitators, Accessories, and Parts
03138  *	Evaporative Coolers
03140  *	Fans, Industrial Types: Attic, Exhaust, Forced Draft, etc.
03141  *	Fans, Room Type, Ceiling and Portable Type (Stationary and Oscillating)
03143  *	Filter Coating, Adhesive, Coil Cleaners, Degreasing Solvents, etc.
03144  *	Filters, Air Conditioning (Permanent Type)
03145  *	Filters, Air Conditioning (Disposable Types)
03146  *	Filters and Filter Media, Evaporative Cooler
03149  *	Filter Frames, Metal
03150  *	Freon
03151  *	Furnaces, Central Heating Type (Forced Air, Gas Fired)
03153  *	Grilles, Diffusers, Registers, etc.
03155  *	Hand Tools, Air Conditioning and Heating Service Type (Includes Leak Detectors)
03156  *	Heat Pumps
03157  *	Heaters, Electric (Baseboard Type) and Parts
03158  *	Heaters, Electric (Panel or Wall Type) and Parts
03159  *	Heaters, Electric (Portable) and Parts
03160  *	Heaters, Gas-Fired (Space Type, Vented and Unvented) and Parts
03161  *	Heaters, Gas-Fired (Wall Type, Vented and Unvented) and Parts
03162  *	Heaters, Kerosene or Oil Fired (Space Type, Vented and Unvented) and Parts
03163  *	Heaters, Space, Steam
03165  *	Heating Elements, Electric
03169  *	Odor Control Equipment (Indoor)
03172  *	Pumps, Descaling Acid
03173  *	Pumps, Refrigerant Circulating
03174  *	Pumps, Refrigerant Vacuum
03178  *	Roof Ventilators, Power Driven
03179  *	Roof Ventilators, Wind Driven
03182  *	Stoves, Wood or Coal
03187  *	Testing and Recording Instruments
03189  *	Thermometers and Gauges
03191  *	Unit Heaters, Electric (Duct and Suspended Types)
03192  *	Unit Heaters, Gas-Fired (Duct and Suspended Types)
03193  *	Unit Heaters, Gas-Fired (Radiant and Infrared, Portable and Stationary)
03194  *	Unit Heaters, Steam and Hot Water Types
03195  *	Ventilators, All Types (See Class 031-78, 79 for Roof Type)
03196  *	Vent Pipes, Fittings, and Accessories