CRD System Commissioning & Performance Testing Flashcards

What is the primary purpose of commissioning a residential geothermal heat pump system before handover to the homeowner?

Answer: To verify the system operates according to design specifications and performance standards

Commissioning ensures the installed system meets the design intent, operates safely, and delivers expected efficiency before the owner takes possession.

During geothermal system commissioning, what does measuring the system's Coefficient of Performance (COP) verify?

Answer: The ratio of heating output to electrical energy input

COP measures how efficiently the system converts electrical energy into useful heating output, confirming the unit performs as specified.

Which instrument is used to measure ground loop flow rate during commissioning of a closed-loop geothermal system?

Answer: Flow center with integrated flow meter or a clamp-on ultrasonic flow meter

Flow rate must be measured directly using a flow meter integrated in the flow center or a clamp-on ultrasonic meter to verify adequate circulation.

What entering water temperature (EWT) range to the heat pump is typically required during commissioning of a vertical closed-loop system in the US heating season?

Answer: 25°F to 60°F depending on ground conditions and loop design

During heating, EWT for vertical closed loops typically ranges from 25°F to 60°F depending on ground temperature, loop length, and design conditions.

A geothermal system commissioning technician records a leaving water temperature (LWT) significantly higher than design in cooling mode. What does this most likely indicate?

Answer: Insufficient ground loop flow rate or an undersized loop field

High LWT in cooling mode suggests the loop cannot adequately reject heat, pointing to low flow rate or an undersized ground loop.

Which document is typically completed and left with the homeowner after geothermal system commissioning?

Answer: A commissioning report including measured flow rates, temperatures, pressures, and COP calculations

A commissioning report documenting all measured parameters provides the homeowner and future technicians with a performance baseline for the system.