Agilent 1100 pump pressure/flow rate problem

[woolab]

Hello,
I have a pump pressure/flow rate problem with agilent 1100 binary pump. I found a similar post here and quite similar problem that with lower pressure (45 bar with 60%ACN/Water) than usual (83bar) and only 70% flow rate (0.7ml for 5 min with 0.2 ml/min setting). But without column it flows 100%. We have no visible leak anywhere.
So we changed outlet check value, active inlet cartridege, and pump seal - but still no success.
One thing we noticed is that with one pump pressure got lower 55 to 45, then the other pump also got lower to the same.
Any suggestion?
I would appreciate any help on this.



Margot-1 wrote:
I have an Agilent 1100 quaternary pump with a flow rate problem. The flow rate tests low ~0.7-0.8 mL/min when set at 1.0 mL/min. This was tested at the end of a column in a 10 mL grad cylinder after 10 minutes. The column pressure was ~220 bar and steadily rose to ~270 bar with 1:1 ACN:H2O mobile phase. Each of four channels (ABCD) tested the same. The pump has new check valve cartridges (inlet & outlet), a new purge valve filter and a new gradient mixing valve. I did not replace the active inlet valve that holds the inlet cartridge yet. The flow rate tests fine with a coil of peek tubing (without a column) at 1.0 mL/min at ~40 bar or at 5 mL/min at 170 bar. We had similar low flow rate results with a brand new column. Any ideas?

[uzman]

Did you check the purge valve outlet during the run ?
Take out the waste tubing and look for droplets if there is a leak.

[AServiceTech]

Make sure the solvent inlet filters (the glass 20 um filters) are not clogged. Also test the flow rate with a pure solvent (water for example or isopropanol) and set the Pump Compressibility to the correct setting (found under More Pump Parameters). To check the Active Inlet Valve function, open the purge valve and set pump to 5 mL/min. Introduce a bubble into the solvent line by lifting the line out of solvent. The bubble should move and stop, move and stop....if it does not then problem with Active Inlet Valve. During normal operation with purge valve closed you can get a sense of Outlet Valve integrity by monitoring the pressure ripple (should be less than 0.5%).

[R13]

Your question is somewhat confusing:
"So we changed outlet check value, active inlet cartridege, and pump seal - but still no success.
One thing we noticed is that with one pump pressure got lower 55 to 45, then the other pump also got lower to the same."

If we speak about G1312 then you have actually TWO pumps. So there are two sets of inlet/outlet cartridges to investigate, hovever the pressure is not measured in each pump head individually but at the exit after the mixer - so there is just one pressure value. Since each pump head is delivering eiter solvent A or B at different speed, if one of them stops working properly flow/pressure in whole system is influenced. If the one pump head has bad check valve it is even possible that another pump forces the solvent into the failed channel "backwards".

First step is to find which one is bad. For that You have to set solvent delivery 100% from channel A then 100 % B and measure flow, observe the pressure. It should be the same for both channels.

There is a pressure drop/leak test described in the manual (You need stainless stell plug for that), but I doubt that a leak would cause your problem unless it is caused by completely destroyed purge valve (it could happen if overtightened) but that should be indicated by moving solvent/bubbles in the waste tubing (with closed valve).

[Klaus I.]

Hello,
I have a pump pressure/flow rate problem with agilent 1100 binary pump. I found a similar post here and quite similar problem that with lower pressure (45 bar with 60%ACN/Water) than usual (83bar) and only 70% flow rate (0.7ml for 5 min with 0.2 ml/min setting). But without column it flows 100%. We have no visible leak anywhere.
So we changed outlet check value, active inlet cartridege, and pump seal - but still no success.
One thing we noticed is that with one pump pressure got lower 55 to 45, then the other pump also got lower to the same.
Any suggestion?
I would appreciate any help on this.

Sorry but I am not able to understand you problem. Can you be so kind and describe your problem without refering to other threads, please.

Please describe your instrumentation, your observations and the actions you have taken on a historically correct way. Thank you.