The capacity of an oil burner fuel pump should be sufficient to handle
the total vacuum in the system. The vacuum is expressed in
inches and can be determined by the following procedure:
• 1 inch of vacuum for each foot of lift
• 1 inch of vacuum for each 90° elbow in either the suction or return lines
• 1 inch of vacuum for each 10 feet of horizontal run (3?8-inch OD line)
• 1 inch of vacuum for each 20 feet of horizontal run (1?2-inch OD line)
After you have calculated the total vacuum, you can use these data to select the most suitable pump for the burner. Table 1-1 lists various vacuums and suggests appropriate pump capacities.