WALMART MAINTENANCE HVAC and Refrigeration 5

Question 1

A Walmart store's HVAC system shows a large temperature split between supply and return air ducts. What does this indicate?

Accepted Answer

Good heat transfer — the system is functioning efficiently

Answer

A large temperature differential (typically 16–22°F) between return and supply air indicates the evaporator coil is effectively removing heat from the air.

Question 2

What is the primary reason Walmart refrigeration cases use anti-sweat heaters on door frames and mullions?

Accepted Answer

To prevent moisture condensation that can cause mold and slipping hazards

Answer

Anti-sweat heaters warm door frames and mullions above the dew point to prevent condensation that could cause mold growth or create slip hazards.

Question 3

What refrigerant leak detection method is required by EPA regulations for large commercial refrigeration systems with charges over 50 lbs?

Accepted Answer

Regular leak testing with automatic leak detection or scheduled inspections

Answer

EPA Section 608 requires systems with more than 50 lbs of refrigerant to have automatic leak detection or undergo scheduled leak inspections.

Question 4

In a variable refrigerant flow (VRF) system serving a Walmart office area, what determines how each indoor unit calls for heating or cooling?

Accepted Answer

Individual room thermostats or controllers for each indoor unit

Answer

VRF systems allow each indoor unit to be independently controlled by its own thermostat or remote controller to meet individual zone demands.

Question 5

What is the purpose of a crankcase heater on a refrigeration compressor?

Accepted Answer

To prevent refrigerant from migrating into the compressor oil during off cycles

Answer

Crankcase heaters keep compressor oil warm during off cycles, preventing refrigerant from mixing with oil, which can cause liquid slugging on startup.

WALMART MAINTENANCE Practice Test

WALMART MAINTENANCE Practice Test

WALMART MAINTENANCE HVAC and Refrigeration 5