WALMART MAINTENANCE Building Systems 5 — Questions and Answers
Question 1: What is the purpose of a backflow preventer on a building's water supply connection?
- Increase incoming water pressure
- Prevent contaminated water from flowing back into the municipal supply (Correct answer)
- Reduce water hammer in supply lines
- Filter sediment before it enters the building
Correct answer: Prevent contaminated water from flowing back into the municipal supply
Backflow preventers ensure that contaminated or non-potable water cannot reverse flow and enter the public water supply system.
Question 2: Which type of lighting has the longest rated lifespan and highest energy efficiency for commercial applications?
- Metal halide
- Fluorescent T8
- LED (Correct answer)
- High-pressure sodium
Correct answer: LED
LED lighting offers the longest lifespan (50,000+ hours) and highest energy efficiency of all commercial lighting technologies currently available.
Question 3: What does a condensate drain line do in a split-system air conditioner?
- Returns refrigerant from evaporator to compressor
- Removes water that condenses on the evaporator coil during cooling (Correct answer)
- Drains excess refrigerant oil from the system
- Equalizes pressure between indoor and outdoor units
Correct answer: Removes water that condenses on the evaporator coil during cooling
As warm humid air passes over the cold evaporator coil, moisture condenses and must be drained away via the condensate line to prevent water damage.
Question 4: When a circuit breaker trips repeatedly under normal load conditions, what is the most likely underlying cause?
- The breaker needs to be reset more firmly
- The circuit is overloaded or there is a fault in the wiring or connected equipment (Correct answer)
- The panel is receiving too much voltage from the utility
- The neutral wire has become loose at the panel
Correct answer: The circuit is overloaded or there is a fault in the wiring or connected equipment
Repeated tripping indicates the circuit is drawing more current than the breaker's rating due to overload or a wiring/equipment fault.
Question 5: In a building's roof drainage system, what is an 'overflow drain' or 'scupper' designed to handle?
- Normal daily rainfall volumes
- Excess water if primary drains become blocked, preventing roof overload (Correct answer)
- Snow melt during winter months only
- Condensation from rooftop HVAC equipment
Correct answer: Excess water if primary drains become blocked, preventing roof overload
Overflow drains and scuppers provide emergency drainage to prevent dangerous water accumulation if primary roof drains are clogged.
Question 6: What type of maintenance task should be performed on a building's air handling unit filters monthly in a high-traffic retail environment?
- Replace all filters regardless of condition
- Inspect filters and replace when pressure drop exceeds specification or filters are visibly clogged (Correct answer)
- Wash and reinstall existing filters
- Switch filters between intake and return air sides
Correct answer: Inspect filters and replace when pressure drop exceeds specification or filters are visibly clogged
Filters should be inspected monthly and replaced when dirty enough to restrict airflow, as replacement frequency varies with actual conditions.
Question 7: What is the primary purpose of a seismic shut-off valve on a building's gas supply?
- Reduce gas pressure after an earthquake
- Automatically stop gas flow when seismic activity above a set threshold is detected (Correct answer)
- Prevent gas leaks during high-wind events
- Shut off gas when carbon monoxide is detected
Correct answer: Automatically stop gas flow when seismic activity above a set threshold is detected
Seismic shut-off valves automatically close the gas supply when ground movement exceeds a set threshold, preventing gas leaks and fires after earthquakes.
WALMART MAINTENANCE Building Systems 5
What is the purpose of a backflow preventer on a building's water supply connection?