Gasboy Gilbarco Global Pumping Unit Operation Manual - Manual (Page 25)

MDE-4447A Global Pumping Unit Operation and Service Manual · May 2008 Page 21
General Vacuum and Pressure Information Troubleshooting
5 – Troubleshooting
General Vacuum and Pressure Information
The following components are normally associated with pump pressure:
• Control Valve
• Meter
• Computer or Pulser Drive Linkage
• Hose
• Nozzle
The following components are normally associated with pump vacuum:
• Blades
• Rotor/Stator
• Filter
• Bypass Valve and Seat
• Float (opened)
• Installation piping
• Tank Vent Pipe
• Angle Check Valve or Foot Valve
• Tank burial depth
Vacuum readings can vary with each installation. To calculate pump vacuum, proceed as
follows:
1 An inch of mercury is required to lift gasoline 1-1/2 feet. Divide the total lift by 1-1/2 feet to
obtain vacuum.
2 Allow an inch of mercury for each angle check, foot valve, or vertical check valve.
3 Allow an inch of mercury for each 60 feet of piping.
4 Add the readings obtained in steps 1 , 2 and 3 to determine the approximate vacuum reading at
fast flow.
Note: Excessive vacuum indicates a restriction. Low vacuum indicates a leak.