What is the maximum input of the vent for a Water Heater rated at 50,000 BTUH located 3 feet from the chimney, with a rise of 2 feet and a chimney height of 25 feet?

To determine the maximum input of the vent for a water heater rated at 50,000 BTUH, understanding the combustion air requirements and vent sizing is essential. Specifically, for appliances like water heaters, the venting system needs to support the appliance's BTU input while also accounting for its distance from the chimney and the rise in height.

In this scenario, the water heater has an input rating of 50,000 BTUH, which translates into a need for combustion air. When sizing the vent, you use the formula that relates BTU input to cubic feet per hour (cfh) of venting required. For every 1,000 BTUH, approximately 1 cfh of venting is necessary. This approximation helps ensure that the combustion process runs efficiently and safely.

Given the input rating of 50,000 BTUH, we would need at least 50 cfh of venting capacity. However, because of the specifics of this installation—specifically the distance from the chimney (3 feet) and the rise to the vent (2 feet)—there are adjustments to the vent size requirements based on the guidelines provided in the National Fuel Gas Code or local codes.

Increased height and location can allow for some additional venting capacity