CPI Pump, Motor & Heater Inspection 3 — Questions and Answers
Question 1: What is the primary function of the pump strainer basket located in the pump pot?
- To filter fine particles from pool water
- To prevent large debris from reaching and damaging the impeller (Correct answer)
- To regulate flow rate to the heater
- To trap chlorine tablets before they enter the system
Correct answer: To prevent large debris from reaching and damaging the impeller
The pump strainer basket catches leaves and large debris before they reach the impeller, protecting it from damage and clogging.
Question 2: When inspecting a heat pump pool heater, which refrigerant component should an inspector note if visibly iced over during operation in warm weather?
- Condenser coil
- Evaporator coil (Correct answer)
- Compressor housing
- Expansion valve
Correct answer: Evaporator coil
An iced evaporator coil on a heat pump during warm weather indicates low refrigerant charge or restricted airflow, both requiring service.
Question 3: A pool pump motor is rated at 1.5 HP THP (Total Horsepower). What does this designation mean for inspection purposes?
- The motor produces 1.5 HP continuously under all conditions
- The nameplate HP includes service factor, so actual continuous HP may be lower (Correct answer)
- The motor can only be used on pools over 15,000 gallons
- THP means the motor is variable speed capable
Correct answer: The nameplate HP includes service factor, so actual continuous HP may be lower
THP (Total Horsepower) includes the service factor, so the motor's actual continuous-duty HP is less than the stated THP rating.
Question 4: Which condition found during inspection would indicate a pool pump impeller is partially clogged?
- Pump motor runs but flow rate is significantly lower than expected (Correct answer)
- Motor fails to start and hums
- Pump produces excessive noise on startup only
- Water temperature rises above normal
Correct answer: Pump motor runs but flow rate is significantly lower than expected
A partially clogged impeller reduces water flow while the motor continues to run, resulting in lower-than-expected flow rates.
Question 5: For a gas pool heater, what is the purpose of the pilot assembly or ignition control module?
- To regulate the gas pressure entering the burner manifold
- To ignite the main burner and verify the flame is established (Correct answer)
- To control the water bypass valve around the heat exchanger
- To monitor flue gas temperature for efficiency
Correct answer: To ignite the main burner and verify the flame is established
The pilot assembly or ignition module lights the main burner and uses a flame sensor to confirm ignition before allowing continued gas flow.
Question 6: During inspection, a pool pump is found installed below the water level of the pool. What is the primary benefit of this installation?
- It reduces motor operating temperature
- It allows the pump to operate flooded, improving self-priming ability (Correct answer)
- It lowers electrical consumption
- It prevents thermal expansion in the discharge plumbing
Correct answer: It allows the pump to operate flooded, improving self-priming ability
Installing a pump below the pool water level creates a flooded suction condition, making priming easier and more reliable.
Question 7: An inspector observes green or blue staining on the copper heat exchanger fins of a gas heater. This most likely indicates:
- Normal oxidation from combustion gases
- Corrosion caused by low pH or aggressive water chemistry (Correct answer)
- Improper gas mixture ratio
- High chlorine levels damaging the burner assembly
Correct answer: Corrosion caused by low pH or aggressive water chemistry
Green or blue staining on copper heater components indicates corrosion from acidic or aggressive water chemistry, which can lead to heat exchanger failure.
CPI Pump, Motor & Heater Inspection 3
What is the primary function of the pump strainer basket located in the pump pot?