CPI Pool & Spa Systems Design & Operation 3 — Questions and Answers
Question 1: Which pool heating system type uses a refrigerant cycle to extract heat from outdoor air?
- Gas-fired heater
- Solar thermal collector
- Heat pump (Correct answer)
- Electric resistance heater
Correct answer: Heat pump
Heat pumps use a compressor and refrigerant to extract ambient heat from the air and transfer it to the pool water, making them highly energy-efficient.
Question 2: What is the primary purpose of an equalizer line connected to the bottom of a skimmer?
- To balance chemical levels between skimmers
- To allow the pump to draw water from the main drain if the water level drops below the skimmer weir (Correct answer)
- To equalize pressure between the pump and filter
- To drain the skimmer basket for cleaning
Correct answer: To allow the pump to draw water from the main drain if the water level drops below the skimmer weir
The equalizer line prevents the pump from running dry or drawing air if the pool water level falls below the skimmer opening, by providing an alternate suction path from the main drain.
Question 3: A multiport valve set to the 'waste' position routes water:
- Through the filter and back to the pool
- Through the filter then to a waste line
- Directly from the pump to waste without passing through the filter (Correct answer)
- Back through the filter in reverse for backwashing
Correct answer: Directly from the pump to waste without passing through the filter
The waste setting bypasses the filter entirely, sending water from the pump directly to the drain line, useful for lowering water level or vacuuming heavy debris.
Question 4: What type of valve is most appropriate for throttling (fine-tuning) water flow in a pool system?
- Gate valve
- Ball valve
- Globe valve (Correct answer)
- Check valve
Correct answer: Globe valve
Globe valves are designed for throttling because their internal disc can be precisely positioned to regulate flow, unlike ball or gate valves which are best for on/off service.
Question 5: What is the recommended maximum water velocity in pool suction piping to prevent cavitation?
- 1 ft/sec
- 3 ft/sec (Correct answer)
- 6 ft/sec
- 10 ft/sec
Correct answer: 3 ft/sec
Suction piping should be sized to keep water velocity at or below approximately 3 ft/sec (some codes allow up to 6 on pressure side) to prevent cavitation and excessive head loss.
Question 6: An ultraviolet (UV) sanitization system installed on a pool primarily:
- Raises the free chlorine residual
- Destroys chloramines and pathogens as water passes through the UV chamber (Correct answer)
- Filters out particulate matter below 1 micron
- Ionizes the water to prevent algae growth
Correct answer: Destroys chloramines and pathogens as water passes through the UV chamber
UV systems expose water to UV-C light in a contact chamber, destroying chlorine-resistant pathogens like Cryptosporidium and breaking down combined chlorine (chloramines).
Question 7: Which condition would cause a pool pump to lose prime?
- Oversized filter media
- Air leak on the suction side of the pump (Correct answer)
- High total dissolved solids in the water
- Excessive cyanuric acid levels
Correct answer: Air leak on the suction side of the pump
An air leak anywhere on the suction side allows air to enter the pump housing, displacing water and breaking the siphon that maintains prime.
CPI Pool & Spa Systems Design & Operation 3
Which pool heating system type uses a refrigerant cycle to extract heat from outdoor air?