CSLB HVAC (C-20) Trade

What is the primary purpose of providing combustion air to a gas-fired furnace?

1. ATo cool the furnace electronic control board
2. BTo supply oxygen for complete, safe combustion正确
3. CTo raise the supply air temperature further
4. DTo reduce refrigerant head pressure

为什么: A gas furnace needs adequate combustion air so the burner receives enough oxygen for complete combustion. Insufficient air causes incomplete combustion, producing carbon monoxide and sooting. The CMC specifies required openings or ducts based on the appliance input and the confining space.2022 California Mechanical Code (CMC)

In residential load calculations, what does an ACCA Manual J procedure primarily determine?

1. AThe size and gauge of the supply ductwork
2. BThe building's heating and cooling loads正确
3. CThe refrigerant charge for the condenser
4. DThe electrical service size for the panel

为什么: Manual J is the industry-standard residential load calculation method. It estimates the sensible and latent heating and cooling loads by accounting for construction, insulation, windows, orientation, infiltration, and local design temperatures. Equipment is then selected to match those calculated loads.California Energy Code (Title 24)