Agilent 1200 Binary SL High Pressure

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8 posts Page 1 of 1
Hello all,

Our lab just acquired a 1200 stack with a BIN SL pump. Now, we have an unusual high pressure, with open valve, it fluctuates between 10-15 bar. With close valve, at 2ml/min, it shoots up to 400 bar.

I attempted to change the pump head A with another one that is working great, and yet the problem persists.

Also, we are using Chemstation B.04.03 SP2 and under pump control, only H2O is listed, and a message displays "the seperate Agilent LC Diagnostic Software provides ability to calibrate pump for individual solvent". We are using the regular solvents, Isopropanol, methanol, acetonitrile etc...

Any tips or guidelines would be very appreciated.

Thank you all,
An open Prime/Purge valve on an Agilent 1200 Binary pump showing 10-14 bars with any solvent flowing at 1mL/min (or even 2mL/min) indicates that the valve is damaged OR far more likely, the PTFE frit is dirty (IOW: The system may have been abused and/or has not been serviced). 0-1 bars with the valve open would be normal. Please replace the PTFE frit (see below for more info). *Purge Valve open = no obstruction = open to atmosphere = no back-pressure.

With the valve closed, flow at 2 mL/min and a column in-line, the pressure could be virtually any value as pressure is a function of many things (i.e. solvent choice, column dimensions, temperature etc). A narrow column used with a viscous solution could easily max out the pressure.

Q: Is the pump connected to the rest of the HPLC system? If so, then an obstruction is within the pump's own flow path and should be simple to sort out (check each high-pressure head and channel separately; check the 'T'; check the pump's Prime/Purge valve and also the pump's outlet line).

If the pump is connected to the rest of the HPLC system (as it normally would be), then unless you provide more information there is no way to estimate what the "normal" system back-pressure might be. You may or may not have an obstruction. Please contact someone who is familiar with and has basic training in HPLC to assist you. Using a "learn as you go" will not work for HPLC. Verifing operation of each component part plus tracing the flow path back from the detector outlet through the system to the bottles will find it (knowledge of the full flow path and operation is needed). Be sure to check and rule-out the column early on as the source of any obstruction first.

In all cases, before using an HPLC system, please invest in training to learn the flow path and basic operation, including the easy to use ChemStation Rev B. software. It takes >5 years bench time for most to learn the basics.

Lastly, please replace the PTFE frit every month (inside the Prime -Purge valve) as it is there to protect the flow path of the system from both the normal piston seal debris AND any particulate matter that is accidentally introduced to the flow path through the bottles. These inexpensive ($5) and critical consumable items should be kept on hand at all times.
Not a FRIT or a pump head related issue, as stated the pump head was switched. I am trying to figure out what else in the pump may cause the issue? I have already bypassed the mixer with a low volume, yet the issue persists.

Already, narrowed down to the pump, the column is good and the path is clear.

Thank you for your feedback, when I cross 25 years in HPLC, will let you know.
Again, if an open prime/purge valve shows high pressure, then the valve or PTFE frit is an issue. The Prime purge valve is pump head specific so would follow the pump head if you switched it out. Mixer's not likely to cause pressure issues (serviced thousands, never seen a mixer on an 1100/1200-series plug). REAL obstructions are found at points that narrow, 'T', valve, pulse dampener.... A Binary pump has TWO separate high-pressure heads so you can troubleshoot by only running one-at-a-time to determine if there is an obstruction or damage. Flush one, observe pressure. Repeat with second. Are they the same? Test with pure Methanol or IPA for flow. If the pressure transducer is damaged, then a failure here usually results in a "stuck" reading (i.e. high) with no changes observed or fast switching between two values only. Replace the sensor if it is damaged. Contact Agilent service for local repair.
Multidimensional wrote:
Again, if an open prime/purge valve shows high pressure, then the valve or PTFE frit is an issue.

When purging, we always checked that pressure pumping aqueous phase 5ml/min out the purge valve was under 10 bar; as pressure approached 10 bar, we installed a new frit.

Of course in later years our pointy-haired boss felt that such purge frit replacement called for full cGMP certification after "a repair", ridiculous.
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Multidimensional wrote:
A Binary pump has TWO separate high-pressure heads so you can troubleshoot by only running one-at-a-time to determine if there is an obstruction or damage.

We only had one binary unit (1100) so my experience with that was limited. But I'd start with his suggestion above.
Consumer Products Guy wrote:
Multidimensional wrote:
Again, if an open prime/purge valve shows high pressure, then the valve or PTFE frit is an issue.

When purging, we always checked that pressure pumping aqueous phase 5ml/min out the purge valve was under 10 bar; as pressure approached 10 bar, we installed a new frit.

Both pump heads are showing the same issue. No matter the channel.

The system includes an HiP ALS SL, TCC, VWD and a degasser.

The substitute pump head is tested and was shown stable and consistent good pressure.

FYI, we started by changing the PTFE frit and seals, before moving on with other initiatives.
Hello all,

We finally fixed the issue, it was the damper. Once we changed, all the readings were as expected.
Thanks for posting a follow-up/solution, so others can learn.
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