Thermo Scientific
Accela Pump Hardware Manual
43
5
Diagnostics
Use the following procedures to monitor the pump pulsation, test the pump proportioning
accuracy, and determine the delay volume of the pump.
Monitoring the Pump Pulsation
The pump continuously monitors the system pressure and bases its pressure readout on a 30 s
interval. The pump pulsation should be less than 1% at backpressures greater than 100 bar
(1450 psi).
Trapped air bubbles, contaminated proportioning valves, or contaminated check valves can
cause excessive pump pulsation. If the pulsation of the pump is greater than 1 percent at
pressures greater than 100 bar, purge air out of the piston chambers, and clean the
proportioning valves and the check valves (see
“Minimizing Pump Pulsation”
on
page 55
).
If you cannot reduce the variation in backpressure by performing these procedures,
disassemble and clean the LDA, and replace the primary piston seals (see
“Replacing the
Primary Pistons Seals”
on
page 67
).
The following topics describe how to monitor the pump pulsation from the data system:
•
Using Xcalibur to Monitor the Pump Status
•
Using ChromQuest to Monitor the Pump Status
Contents
•
Monitoring the Pump Pulsation
•
Testing the Pump Proportioning
•
Determining the Delay Volume of the Pump
Note
Because the Accela Pump does not use electronic pulse damping, the Accela Pump
pressure fluctuation often appears to be higher than that for conventional pumps.
Note
All low-pressure HPLC pumps require eluents that have been properly degassed.
The Accela Pump has a built-in vacuum degasser. Plumbing the pump to bypass this
degasser introduces a potentially unacceptable level of air into the piston chambers.
