Contractor Exam Questions And

CA D71 Solar Water Heating Systems Contractor Exam Questions And Correct Answers (Verified Answers) Plus Rationale2026 Q&A| Instant Download Pdf

What is the primary purpose of a solar water heating system?

• Reduce air conditioning costs
• Generate electricity
• Heat water using solar energy
• Provide lighting

Rationale: The main function of a solar water heating system is to convert

solar energy into thermal energy for water heating.

• Which type of solar collector is most commonly used for residential

solar water heating?

• Parabolic trough
• Fresnel lens
• Flat-plate collector
• Solar tower

Rationale: Flat-plate collectors are widely used due to their cost-

effectiveness, durability, and efficiency for residential water heating.

• What is the function of a heat exchanger in a solar water heating

system?

• Store solar energy
• Transfer heat from the solar fluid to the potable water
• Pump water through the system
• Reflect sunlight 1 / 3

Rationale: A heat exchanger allows heat from the solar fluid to

transfer to potable water without mixing the fluids.

• Which fluid is typically used in a closed-loop solar water heating

system in cold climates?

• Tap water
• Antifreeze solution (glycol mixture)
• Saltwater
• Diesel

Rationale: Glycol-based antifreeze is used to prevent freezing in cold

climates while circulating heat.

• What is the ideal tilt angle for a fixed flat-plate solar collector in most

locations?

• 0 degrees
• Horizontal
• Approximately equal to the latitude of the location
• 90 degrees

Rationale: Tilting the collector at the latitude angle maximizes solar

exposure throughout the year.

• What is the main advantage of a direct (open-loop) solar water heating

system?

• Does not freeze in cold climates
• Requires no maintenance
• Higher efficiency since water is heated directly in the collector
• Uses antifreeze

Rationale: Direct systems heat potable water directly, avoiding heat

exchanger losses, suitable for areas without freezing temperatures.

• Which component ensures safe pressure levels in a solar water heating

system?

• Expansion tank
• Pump
• Pressure relief valve
• Check valve

Rationale: A pressure relief valve prevents overpressure situations

that could damage the system.

• What is the main role of an expansion tank in a closed-loop solar water

heating system?

• Increase water temperature 2 / 3

• Accommodate thermal expansion of the fluid
• Filter the water
• Reduce heat loss

Rationale: As fluid heats and expands, the expansion tank prevents

excessive pressure build-up.

• What is the recommended insulation for pipes in a solar water heating

system?

• PVC tubing
• Aluminum foil
• High-temperature foam or fiberglass insulation
• No insulation

Rationale: Proper insulation minimizes heat loss in the piping,

improving system efficiency.

• What is a key consideration when sizing a solar storage tank?
• Color of the tank
• Daily hot water demand and solar collector output
• Electrical supply
• Roof orientation

Rationale: Storage tank size should match daily hot water

consumption and the amount of heat collected.

• Which type of solar water heating system uses pumps to circulate

fluid?

• Passive batch system
• Active system
• Thermosyphon system
• None of the above

Rationale: Active systems use pumps and controllers to circulate fluid

between the collector and storage tank.

• What is the function of a check valve in a solar water heating

system?

• Reduce water temperature
• Increase pressure
• Prevent backflow of fluid
• Expand fluid volume

Rationale: Check valves ensure fluid flows in one direction,

preventing reverse circulation.

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