WALMART MAINTENANCE Building Systems 3 — Questions and Answers
Question 1: What is the purpose of an expansion tank in a closed-loop hydronic heating system?
- Store extra water for emergencies
- Absorb pressure increases as water expands when heated (Correct answer)
- Filter debris from the loop
- Increase system water temperature
Correct answer: Absorb pressure increases as water expands when heated
An expansion tank accommodates the increased volume of water as it heats up, preventing dangerous pressure spikes in a closed system.
Question 2: Which lighting control system automatically dims or turns off lights based on occupancy?
- Dimmer switch
- Occupancy sensor (Correct answer)
- Photocell controller
- Timer relay
Correct answer: Occupancy sensor
Occupancy sensors detect motion or body heat to automatically control lighting, reducing energy waste in unoccupied spaces.
Question 3: What is the recommended minimum slope for a commercial flat roof to ensure proper drainage?
- 1/8 inch per foot
- 1/4 inch per foot (Correct answer)
- 1/2 inch per foot
- 1 inch per foot
Correct answer: 1/4 inch per foot
A minimum slope of 1/4 inch per foot (2%) is the standard requirement for flat roofs to prevent ponding water.
Question 4: In electrical systems, what does 'grounding' a circuit primarily protect against?
- Voltage fluctuations
- Electric shock and equipment damage from fault currents (Correct answer)
- Power surges from lightning only
- Overloading the neutral wire
Correct answer: Electric shock and equipment damage from fault currents
Grounding provides a safe path for fault current to flow, tripping the breaker and protecting people and equipment from dangerous voltages.
Question 5: A building's exhaust fan is making excessive noise. Which component is most likely the cause?
- Fan blade pitch angle
- Worn or loose bearings (Correct answer)
- Motor winding resistance
- Incorrect voltage supply
Correct answer: Worn or loose bearings
Worn or loose bearings are the most common cause of excessive fan noise and require lubrication or bearing replacement.
Question 6: What is the purpose of a P-trap in a plumbing drain system?
- Prevent pipe corrosion
- Maintain a water seal to block sewer gases (Correct answer)
- Regulate drain flow rate
- Filter solids from wastewater
Correct answer: Maintain a water seal to block sewer gases
The P-trap holds a small amount of water that creates a seal preventing sewer gases and odors from entering the building.
Question 7: When inspecting an overhead door's spring system, what safety precaution is most critical?
- Wear steel-toed boots
- Never adjust torsion springs without proper training and tools (Correct answer)
- Always unplug the opener first
- Test the door balance monthly
Correct answer: Never adjust torsion springs without proper training and tools
Torsion springs are under extreme tension and can cause severe injury or death if released suddenly without proper training and winding bars.
WALMART MAINTENANCE Building Systems 3
What is the purpose of an expansion tank in a closed-loop hydronic heating system?