FSD Troubleshooting & Repair Flashcards
6 cards from real FSD practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 FSD Troubleshooting & Repair flashcards as text
What typically causes a fire damper to rattle during normal HVAC system operation?
Answer: Loose blades or worn pivot bearings allowing blade vibration from airflow
Rattling is most often caused by loose blades or worn pivot bearings, which allow damper components to vibrate as air flows past them during normal HVAC operation.
How should a technician handle a fire damper found with a broken torsion spring?
Answer: Replace the spring with an OEM-specified part and retest the damper for full closure
A broken torsion spring must be replaced with the OEM-specified part to restore proper closure force, and the damper retested to confirm it fully closes.
What does excessive play or looseness in a damper's blade pivot point indicate?
Answer: Worn bearings or pivot hardware that will prevent reliable full closure
Excessive play at the pivot point indicates worn bearings or hardware that can cause incomplete or unreliable blade closure during an actual fire event.
When a combination fire/smoke damper fails to reopen after a test cycle, what component is most likely defective?
Answer: The spring-return actuator has lost spring tension or the motor is burnt out
Failure to reopen after a test most commonly points to a spring-return actuator that has lost return tension or has a burnt-out motor preventing it from driving the damper back to the open position.
Per UL 555S, what is the standard leakage classification used to evaluate smoke damper performance after repair?
Answer: Class I, II, or III, based on leakage rate at rated pressure
UL 555S classifies smoke damper leakage as Class I, II, or III based on measured leakage rates at specified test pressures, and a repaired damper must meet its original class rating.
How should a failed thermal element (fusible link) be properly documented before it is discarded?
Answer: Record the temperature rating, location, and condition in the inspection report with photo evidence
A failed fusible link must be documented in the inspection report with its rated temperature, damper location, condition at failure, and photographic evidence before disposal.