Name(Required)

First Last

Email(Required)

A fan underperforming design conditions is always a byproduct of system effect.(Required)

True

False

The area to the left of the "do not select" curve is also commonly referred to as(Required)

The System Effect region

The surge or stall region

The unstable area

The gray area

Peak performance region

Low airflow and Low Static are a common fan law relationship and rule out the possibility of system effect.(Required)

True

False

Which of the following do NOT contribute to system effect and unstable fan performance?(Required)

Turbulent airflow at the inlet.

Turbulent airflow at the outlet.

Abrupt duct transitions

Laminar airflow at the inlet

Field modified duct connections.

Before diagnosing or quantifying systemm effect, which of the following are need to be measured.(Required)

Total airflow

Total static

Brake horsepower

Fan RPM

All of the above

A fan LOW on airflow but above design brake horsepower (BHP) may be a symptom of system effect.(Required)

True

False

An outlet duct installed counter to the direction of fan rotation is an example of which type of issue?(Required)

Belt slippage

System effect due to poor outlet configuration

Over-speed condition

Motor phase imbalance

Insufficient duct insulation

Which of the following is TRUE regarding turning vanes in ductwork?(Required)

Turning vanes are only necessary on supply-side ductwork

Turning vanes installed backwards can worsen flow patterns rather than improve them

Turning vanes eliminate all system effect losses

Turning vanes are not referenced in any AMCA publications

Turning vanes should only be installed by the fan manufacturer

Per AMCA guidelines, what is the recommended minimum straight duct length at the fan outlet for full velocity pressure recovery?(Required)

1 equivalent duct diameter

2.5 to 6 equivalent duct diameters

10 equivalent duct diameters

No straight duct is required if turning vanes are present

It depends entirely on the fan manufacturer

AABC TAB Talk March 2026 Quiz: Diagnosing System Effect Common Causes & Where to Start

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