MDE-4334C Atlas Start-up and Service Manual · April 2008
Page 7-21
Measuring Pressure and Vacuum
Hydraulic/Mechanical Components
To measure dry vacuum for pumps, proceed as follows:
1
Shut off power to the unit. Multiple disconnects may be required. Use OSHA Lock-out and
Tag-out procedures.
2
Drain the Bennett GPU unit of all fuel. Use an approved container. Refer to
on
. Clean up any spills promptly.
3
Plug the pumping unit inlet. Use a flat rubber disc between the union halves or use a pipe plug
in the lower half of the inlet union.
4
Check the belt tension between the pump and motor. Refer to
.
5
Restore power to the unit.
6
Read the vacuum gauge. Newly installed units should read 8 inches Hg (mercury) or above.
Older units (about 1,000 hours of service) should read approximately 4 inches Hg.
7
After the testing is complete, shut off power at the circuit breaker.
8
Remove the gauge and install the plugs that may have been removed earlier, using UL-
approved pipe sealant suitable for the fuel involved.
9
Remove inlet plugs and reconnect the inlet plumbing securely.
10
Restore power and check for leaks.
Measuring Wet Vacuum and Pressure for Pump
This test is useful when the flow output is low. Always follow all safety Warnings and
Cautions.
To measure wet vacuum and pressure for pumps, proceed as follows:
1
Shut off power to the unit.
2
Check the belt tension between the pump and motor. Refer to
on
.
3
Install pressure and vacuum gauges.
4
Restore power and operate the unit with both pressure and vacuum gauges attached. Use an
approved container to collect fuel. Clean up any spills promptly.
5
Record the discharge pressure with the nozzle opened fully, and then with the nozzle closed.
6
Record the vacuum pressure with the nozzle opened fully, and then the nozzle closed.
7
Record the flow rate with the nozzle opened fully.
8
Compare readings with the