MDE-4334C Atlas Start-up and Service Manual · April 2008
Page 7-15
Measuring Pressure and Vacuum
Hydraulic/Mechanical Components
Measuring Pressure and Vacuum
• Wear eye protection. Residual pressure and entrapped fuel may still be present
and may drain or spray while removing parts.
• Fire and explosion could result in severe injury or death.
• Test and close the involved shear valves. Shut off power to the unit.
• Remove parts slowly. Collect fuel in approved containers.
• Clean up all spills promptly.
WARNING
Using the Pressure Gauge
Use pressure gauges and vacuum gauges to test pumps and dispensers when:
• Flow rate is too low
• Motors fail prematurely or stall (pump only)
• Units take a long time to prime (pump only)
• Units are noisy (pump only)
The use of a combined vacuum and pressure gauge eliminates the need to carry more than one
gauge.
Figure 7-6: Typical Pressure Gauge Dial
0
20
100
40
80
60
PSI
PRESSURE
Typical
Pressure
Gauge Dial
Face
If gauge readings are erratic, it indicates that the gauge needle pulsations need to be snubbed.
The following is recommended:
• Always use accurate, calibrated gauges. Using a gauge snubber or a dampened gauge
helps prevent gauge damage and to obtain a more accurate reading. Liquid filled gauges
that dampen readings can also be used.
• Use gauges that have appropriate scales for reading in Pounds Per Square Inch (psi) (scale
0-100 psi) for pressure and 0-30 Hg (inches of mercury) for vacuum.