For appliances designed to operate at 14 inches w.c. or less, overpressure protection devices are needed if the service supply pressure exceeds what psi?

For appliances designed to operate at a low gas pressure of 14 inches water column (w.c.) or less, it is crucial to have overpressure protection devices when the service supply pressure exceeds a certain threshold. In this case, the threshold is 2 psi.

When the supply pressure surpasses this limit, there is a risk that the appliance could receive more gas than it is designed to handle, potentially leading to unsafe operating conditions such as excess pressure in the combustion chamber, which could cause malfunctions, increased emissions, or even hazardous situations like leaks or explosions. Therefore, overpressure protection devices are required to monitor and regulate the gas supply, ensuring that the appliance remains safe and operates within its specified pressure parameters.

The choice of 2 psi as the limit is based on established safety standards and codes to protect low-pressure appliances, and it ensures proper function without exceeding the safe operating limits. This standard is critical for maintaining safety and efficiency in systems that operate under specific low-pressure conditions.