Installation of Warm-Air Heating and HVAC Systems

Install furnaces in the correct orientation (upflow, downflow, or horizontal) to match the duct layout and manufacturer listing.

Maintain listed clearances to combustibles around the furnace, vent, and plenum to prevent fire hazards.

Provide required service access, including a passageway, platform, and light for attic or confined installations.

Supply adequate combustion air sized per the CMC based on appliance input and whether the space communicates with indoors or outdoors.

Use two openings, one high and one low, when venting a confined space to provide both combustion air and heat relief.

Vent Category I appliances with listed Type B vent and condensing (Category IV) appliances with listed plastic pipe such as PVC or CPVC.

Terminate flues and vents outdoors at listed heights and clearances from windows, doors, and air intakes.

Size liquid and suction lines from manufacturer tables based on capacity, line length, and vertical rise, and insulate the suction line.

Flow dry nitrogen through tubing while brazing to prevent internal oxide scale.

Route condensate to an approved drain with proper slope, and provide a secondary pan or float switch where leakage could cause damage.

Pressure test and evacuate the line set to remove moisture and non-condensables before charging.

Size gas piping from code tables using appliance input, pipe length, and allowable pressure drop, and install a sediment trap at the appliance.

Verify correct voltage, polarity, and grounding before energizing, and provide a readily accessible disconnect within sight of the outdoor unit.

Seal all duct joints with mastic or listed tape to prevent leakage and meet California energy requirements.

Do not take return air from a garage or other space where it could pick up combustion products or flammable vapors.