Skip to main content

Refrigeration & Air Conditioning Mechanic Red Seal · Question

When performing a commissioning check on a new commercial ventilation system, a technician uses a balometer (air capture hood) to measure airflow at a supply diffuser. The measured flow is significantly lower than the design specification. Which of the following is the most probable immediate cause?

A heavily loaded or dirty filter bank increases the static pressure drop across the filter, which reduces the effective airflow delivered by the fan. This is a

Start free practice for Refrigeration & Air Conditioning Mechanic Red Seal

500 questions · no signup required · 40 free questions per day

Start Practice →

Question: When performing a commissioning check on a new commercial ventilation system, a technician uses a balometer (air capture hood) to measure airflow at a supply diffuser. The measured flow is significantly lower than the design specification. Which of the following is the most probable immediate cause?

Answer options:

  • The fan motor has seized due to overheating
  • The supply ductwork is undersized for the required airflow volume
  • The outdoor air intake damper is stuck fully open, causing excessive outside air infiltration ✅ The filter bank upstream of the fan is heavily loaded with accumulated dirt

Correct answer: The filter bank upstream of the fan is heavily loaded with accumulated dirt

Explanation: A heavily loaded or dirty filter bank increases the static pressure drop across the filter, which reduces the effective airflow delivered by the fan. This is a common and direct cause of reduced airflow.

Start free practice for Refrigeration & Air Conditioning Mechanic Red Seal

500 questions · no signup required · 40 free questions per day

Start Practice →

More about Refrigeration & Air Conditioning Mechanic Red Seal

Related Questions

More for Refrigeration & Air Conditioning Mechanic Red Seal candidates

Ready to practice?

Free, no signup required. Build a wrong-question list as you go.

Start Free Refrigeration & Air Conditioning Mechanic Red Seal Practice →

Related courses

Other Canadian certifications candidates often prepare for alongside this one.