Diagnostic Testing & Troubleshooting Flashcards

What is the primary purpose of performing diagnostic testing before installing a radon mitigation system?

Answer: To determine optimal sub-slab communication and suction point locations

Diagnostic testing identifies where suction points should be placed by assessing sub-slab communication and soil permeability.

During a pressure field extension test, a manometer is inserted into a diagnostic hole. What result indicates good sub-slab communication?

Answer: A negative pressure reading similar to that at the suction pit

A negative pressure reading at the diagnostic hole similar to the suction pit pressure confirms the sub-slab is well-interconnected.

A smoke pencil or puffer is used during radon diagnostic testing primarily to:

Answer: Identify air pathways and verify airflow direction around the foundation

A smoke pencil visualizes airflow patterns to identify where soil gas may be entering and whether the system is drawing air effectively.

When probing multiple diagnostic holes, what finding indicates that a second suction point is necessary?

Answer: One or more sections show no negative pressure response

Areas that show no pressure response are isolated from the suction point and require their own dedicated suction pit.

A mitigation fan is operating but post-mitigation radon tests show levels above 4 pCi/L. Which diagnostic step should be performed first?

Answer: Check for air bypasses such as open sumps, cracks, or uncapped drains

Air bypasses allow soil gas to enter the living space even when the system is running, and are the most common cause of persistent elevated radon post-installation.

What does a U-tube manometer permanently installed on a mitigation system allow a homeowner to monitor?

Answer: Whether the fan is maintaining negative pressure in the suction pipe

The U-tube manometer provides a visual indicator that the system is functioning by showing fluid displacement corresponding to negative pressure in the pipe.

When troubleshooting a system that has lost vacuum while the fan continues running, which component should be inspected first?

Answer: The suction pipe for cracks, disconnections, or blockages

Physical disconnections, cracks, or obstructions in the suction pipe are the most common mechanical cause of vacuum loss in an otherwise running system.