A temperature and pressure relief device should be installed on each water heater on the hot water side not more than how many inches from the top of the heater?

The installation requirement for a temperature and pressure relief (TPR) valve on a water heater stipulates that it should be placed on the hot water outlet side not more than 6 inches from the top of the water heater. The correct choice indicates that it should be within 3 inches of the top.

This specification is crucial for ensuring that the TPR valve functions properly, allowing it to effectively discharge excess temperature or pressure from the water heater. A positioning within this range helps in preventing any build-up of pressure or temperature that could lead to hazardous conditions, ensuring optimal safety and functionality of the water heater. Furthermore, placing the valve too far from the top could impede its responsiveness to fluctuations in temperature and pressure.

While other options suggest distances greater than 3 inches, these would not comply with the recommended installation practices that aim to enhance safety and prevent potential failures of the water heater from occurring due to improper placement of the TPR valve.