System Maintenance & Troubleshooting Flashcards

When a technician observes channeling (localized high-velocity airflow) through a deep-bed granular media filter, what is the most likely root cause?

Answer: Media settling or void formation within the filter bed

Channeling in granular media beds occurs when settling or void formation creates low-resistance pathways that concentrate airflow, bypassing much of the media.

A facilities manager requests extended filter service intervals to reduce costs. What information should the technician provide to evaluate this request?

Answer: Differential pressure trend data and manufacturer's final resistance rating

Differential pressure trend data compared to the manufacturer's final resistance rating objectively determines whether extending intervals is safe or will risk system performance.

What effect does high relative humidity have on the performance of a standard fibrous air filter?

Answer: It can cause hygroscopic growth of particles, media wetting, and increased pressure drop

High humidity can cause hygroscopic particles to grow, wet the filter media, promote microbial growth, and significantly increase pressure drop.

During post-maintenance commissioning, a technician must verify that airflow through a bank of parallel filter housings is balanced. Which instrument is most appropriate?

Answer: Calibrated balancing hood or pitot traverse in each branch duct

A calibrated balancing hood or pitot tube traverse measures actual airflow in each branch, allowing technicians to verify and adjust balance across parallel housings.

A technician finds that a filter system exhibits normal pressure drop but delivers less than design airflow. Where should the investigation focus?

Answer: Fan motor or drive system performance

Normal pressure drop with reduced airflow points to a problem in the fan or drive system, not the filters, since adequate airflow would produce expected pressure drop if filters were the issue.

Which of the following is the correct sequence for safe filter removal in a hazardous dust application?

Answer: Shut down system, don PPE, bag filter in place before removal, seal and label bag

Shutting down the system, donning appropriate PPE, and bagging the filter in place before removal minimizes worker exposure to captured hazardous dust.

A technician is asked to troubleshoot increased energy consumption in an air filtration system without any change in reported differential pressure. What should be investigated?

Answer: Fan motor efficiency degradation or drive belt slippage

If filters are unchanged but energy use has risen, degraded motor efficiency or slipping drive belts cause the fan to consume more power to maintain the same static pressure.