RMS Diagnostic Testing & Troubleshooting 2

Question 1

During a block-wall depressurization diagnostic, what is primarily being assessed?

Accepted Answer

Whether hollow cores in block walls can be depressurized as a radon entry pathway

Answer

The R-value of the exterior wall insulation

Answer

The structural integrity of the foundation wall

Answer

Moisture levels in the masonry blocks

Question 2

A diagnostic test reveals very low sub-slab airflow despite a high-powered fan. What is the most likely cause?

Accepted Answer

The sub-slab fill has very low permeability such as clay or fine sand

Answer

The sub-slab gravel bed is too thick

Answer

The fan is oversized for the application

Answer

The radon level is naturally below the action level

Question 3

If a mitigation system test pipe shows no pressure differential when the fan is running, what should be checked first?

Accepted Answer

Whether the suction pit properly connects to the sub-slab environment

Answer

The indoor humidity level

Answer

The exterior paint on the exhaust pipe

Answer

The date of the original radon test

Question 4

A crawl space mitigation system shows adequate fan operation, but radon levels remain elevated. Which diagnostic finding is MOST likely?

Accepted Answer

The vapor barrier has holes, gaps, or is not properly sealed to walls and piers

Answer

The fan is placed too close to the ground

Answer

The fan exhaust is too close to a window

Answer

The soil in the crawl space is too dry

Question 5

During troubleshooting, a technician measures higher-than-expected negative pressure but still finds elevated radon levels. What is the most plausible explanation?

Accepted Answer

There is a radon source not addressed by the system such as radon in well water or an isolated sub-slab section

Answer

The fan is not powerful enough

Answer

The manometer is malfunctioning

Answer

Outdoor radon levels are unusually high

Question 6

When should a contractor perform follow-up diagnostic verification after initial system installation?

Accepted Answer

As part of post-installation verification before final sign-off on the job

Answer

Only if the homeowner specifically requests it

Answer

After two years of system operation

Answer

Only when the fan fails or makes noise

Question 7

A mitigation system installed five years ago suddenly shows a significant drop in negative pressure. What is the most likely cause?

Accepted Answer

Fan motor wear or bearing failure reducing fan performance

Answer

Natural degradation of the concrete slab

Answer

Radon levels naturally decreasing over time

Answer

Seasonal changes in outdoor temperature