A boiler horizontal vent must rise a minimum of how many inches per foot?

The requirement for a boiler horizontal vent to rise a minimum of 1 inch per foot is important for ensuring proper drainage of condensate and preventing negative pressure in the vent system. This slight upward slope allows any moisture that forms in the vent to flow back towards the boiler, rather than accumulating and potentially causing blockage or corrosion. Proper venting is crucial for the safe and efficient operation of a boiler, as it helps maintain combustion efficiency and safety by allowing exhaust gases to escape effectively.

The other options suggest slopes that may not be sufficient for effective drainage. An inadequate slope could lead to improper venting, potentially causing operational issues or safety hazards. Therefore, the requirement of a 1-inch rise per foot is established as a standard to ensure reliability and safety in a boiler venting system.