Relief valves in hydraulic sprayers help to prevent pump damage by relieving pressure.

• A. True
• B. False
• C. Only in manual sprayers
• D. Only when tank is full

Answer: (A)

Relief valves prevent pump damage by keeping system pressure within safe limits. In a hydraulic sprayer, the pump builds pressure to push the spray solution to the nozzle. If the flow is restricted (a clogged nozzle, a closed bypass, or a valve shut off while the pump is running), pressure can spike quickly. The relief valve opens at a predetermined pressure and diverts fluid back to the tank or through a bypass, releasing the excess pressure. This protects the pump, hoses, seals, and other components from overpressure and overheating. It operates based on pressure, not tank fullness, so it’s a safety feature in any sprayer, whether manual or powered and regardless of how full the tank is.