Gasboy Gilbarco Global Pumping Unit Operation Manual - Manual (Page 31)

MDE-4447A Global Pumping Unit Operation and Service Manual · May 2008 Page 27
Resolving Problems on Pumping Units Troubleshooting
Figure 5-7: Gauge Troubleshooting 4
Resolving Problems on Pumping Units
Refer to the following tables for specific troubleshooting information.
Problem
The motor starts but the pump does not deliver fuel.
Cause Action
The fuel supply is below the suction stub in
the storage tank. Fill the storage tank.
The vent pipe is plugged in the storage tank. Clean the vent pipe.
The strainer screen or filter assembly has an
obstruction. Remove obstructions from the screen or filter assembly.
The bypass valve is not seated properly due
to wear or obstruction. Check the valve for an obstruction causing the valve to stay
open, and/or replace the bypass valve.
The v-belt is loose or broken. Adjust or replace the v-belt.
There is an obstruction in the atmospheric
float valve. Clean the float and valve area. Check for swelling and binding
in the linkage.
The pump is out of prime. Check for a faulty foot valve in the storage tank or a faulty check
valve in the suction line.
The suction line is leaking. Start the pump and open the nozzle. If bursts of air are felt while
holding a finger on the vent tube, the suction line is damaged.
Repair or replace.
The intake line, foot valve, angle check
valve, or vertical check valve have an
obstruction. Connect a vacuum gauge to the 1/4 inch plug on the filter cover.
Turn the pump on and open the nozzle. A reading of 15 or more
inches of mercury with no flow indicates a complete blockage in
the suction line. Clean the line or replace.
The suction stub in the storage tank is on the
bottom of the tank. Ensure that there is a four-inch clearance.
The control valve has an obstruction. Clean the control valve. It must slide freely in the valve cavity.
The nozzle is not working. Replace the nozzle.
Two pumps are connected to one storage
tank with one suction line. There is a faulty
check valve in one of the supply lines*. Disconnect the vent tube on the idle pump. Install a short
copper tube. Place the end of the copper tube in a container of
liquid. If the liquid is drawn out of the container when the
opposite pump is operated with an open nozzle, the line check
valve is faulty. Replace the check valve.
At Control Valve
Cover At Strainer (or Filter)
Cover
Reading
May Vary
Symptoms: Motor Laboring;
Circuit Breaker Trips; Motor
Failing; Nozzle Closed
Probable Cause:
• Bypass Valve Stuck Shut