Question 76

Pressure relief valves on hot water tanks must open before the water pressure in the tank exceeds 150 psi.

Pressure relief valves are designed to ensure safety by opening to release excess pressure before it reaches dangerous levels. In the case of hot water tanks, the threshold for this safety mechanism is set at 150 psi.

A) 150 psi

This option is correct as it aligns with the safety standards for hot water tanks, ensuring that the pressure relief valve activates before the water pressure reaches this critical level, thus preventing potential hazards.

B) 180 psi

This option is incorrect because setting the pressure relief valve to open at 180 psi would allow the pressure in the tank to exceed the recommended safety threshold, increasing the risk of tank failure or explosion.

C) 210 psi

This option is also incorrect. A pressure relief valve that opens at 210 psi would significantly compromise safety, as it would let the water pressure rise well beyond the acceptable limit, potentially leading to catastrophic failure.

D) 212 psi

This option is incorrect for similar reasons as above. Allowing the tank to reach 212 psi before relief occurs would not provide adequate safety, making it a poor choice for pressure regulation in hot water tanks.

Conclusion

The correct answer, 150 psi, is the established maximum pressure limit for safe operation of hot water tanks. All other options would permit pressure levels that exceed safety standards, which could result in dangerous situations such as tank ruptures or explosions. Thus, 150 psi remains the critical threshold for effective pressure relief.