What is the minimum size of a bottom blow off valve for a boiler?

The minimum size of a bottom blow-off valve for a boiler is specified by regulations to ensure proper operation and safety. A 3/4" valve is considered the minimum size because it provides adequate drainage capacity for the blow-off system. This is critical for effectively removing sediment, sludge, and other impurities that can accumulate at the bottom of the boiler.

Using a valve that is too small could lead to inadequate blow-off capacity, which may result in the buildup of contaminants. Over time, this can affect the efficiency of the boiler and lead to potential damage or hazards. Therefore, adhering to the minimum size ensures that the blow-off system functions correctly and maintains the overall safety and performance of the boiler.

Other options represent valve sizes that are larger than the required minimum, which can be beneficial in terms of efficiency but are not necessary for meeting the baseline safety standards.