Core TradesQuestion 145 of 700
A fuel-burning furnace located in a confined space requires combustion-air openings primarily to:
a.Reduce operating noise
b.Cool the furnace cabinet
c.Supply oxygen for complete combustion and prevent carbon-monoxide buildup
d.Raise the appliance efficiency rating
Explanation
Combustion-air openings provide the oxygen the burner needs for complete combustion; without enough air, incomplete combustion produces dangerous carbon monoxide. The openings are not for noise reduction, cabinet cooling, or raising the efficiency rating, which is set by the appliance design.
Law Reference: 2025 CA Mechanical Code §701.0Practice all 700 questions free — no signup required.
Related questions on this topic
- In a long horizontal drainage line, cleanouts are generally required at intervals not exceeding approximately:
- The discharge pipe from a water heater's temperature-and-pressure (T&P) relief valve must:
- Excessive water velocity in copper supply piping is primarily a concern because it can cause:
- Taking return air for a residential forced-air furnace from a garage is prohibited primarily to prevent:
- A room measures 12 ft by 15 ft with an 8-ft ceiling. To provide 6 air changes per hour, what mechanical ventilation airflow is required?
- Under the California Energy Code, supply ducts run through an unconditioned attic must generally be insulated to a MINIMUM of:
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against California CSLB General Building (B) Trade Examination · How we review