problem with flow rate

[aman]

Hi,
I am using a HP 1090 HPLC machine. It has been running fine unitl yesterday.
A message error of syst,FIRe keeps appearing. The flow rate won't reach the flow rate I have set. I have set a flow rate of 0.300ml/min and it won't reach this flow rate.
Can anyone please help??
Thanks Aman

[JGK]

Have you consulted the troubleshooting section of the manual?

Have you tried any of the actions suggested?

Can you tell us what you have tried? It may help with any advice we can supply.

[Jade.Barker]

I hope this doesn't sounds silly, but have you checked to make sure the mobile resevoir is full?

Don't laugh this *can* happen

[aman]

Yes i have checked that the mobile phase is full.
I have tried inserting a direct gas inlet (instead of through the lab supply) because I thought it may have been a problem with the pressure, but that hasn't helped.
When I put the pump on, the chemstation registers that it is flowing at the rate, but after a few minutes the error message appears.
Should I run through some HPLC grade water?

[Jade.Barker]

Aman,
I am new to HPLC so any advice I have might be elementary...

Is it possible you have a leak in the system? I have heard you can measure the waste volume to ensure the flow is correct. For example, if the flow rate should be 1 ml/ minute: Move the waste tube to a gradutated cylinder and start a timer, after 10 minutes you should have 10 ml.

Then, If the waste is not 10 mls: either some mobile is lost to a leaky connection or tube, OR it could be the pump is not actually moving the correct amount of mobile from the begining.

We had a connection leak after a technician changed the column. The column was located in a losely covered heating block. I was lucky to check there first, because the very small leak could have evaporated away quickly from the heat and I could have missed it.

Also, I understand it is very common to have leaks in the pump area because there are so many seals.

I hope this helps, Good Luck!

[KarenJ]

If your instrument is unable to maintain the flow rate and you have one a thorough check for leaks, I would suspect the pump. Since this came on quickly, you may have dirty check valves. If it is just a small amount of dirt, sometimes you can fix it just by pumping 100% isopropyl alcohol through the pump (bypass your column) for half an hour. You could also try taking the check standards off and sonicating them in IPA for half an hour. If cleaning the check valves doesn't help, I would try changing the seals. If you open up the pump head, you may be able to see which one is leaking if there is moisture in places where it shouldn't be inside the heads. I'm not that familiar with the 1090 system, but the 1100 pump has a little cartridge called an active inlet check valve. Maybe you 1090 has this as well. If this gets dirty, you can have flow problems and the only remedy is to replace the cartridge with a new one. This is easier to change than the seals but more expensive.

Hope this helps.

[dblux_]

Hi,
...
A message error of syst,FIRe keeps appearing. The flow rate won't reach the flow rate I have set. I have set a flow rate of 0.300ml/min and it won't reach this flow rate.
Can anyone please help??
Thanks Aman

I would check whether the frit in mobile phase bottle is not clogged.
After disconecting mobile phase tubing from degasser (if present) or proportioning valve check how easily mobile phase is siphoning through tubing.

[aman]

Hi,
Finally in the lab. Will try some of the suggestions.
Thanks Aman

[aman]

I have checked on the help what syst,FIRe means. The meaning is the solvent pressure is increasing to quickly. (flow reduction)
I have checked the system for leaks and tried flushing it through with IPA, but nothing seems to work.
Are there any other suggestions as to where the problem might lie??
Thanks Aman

[Jade.Barker]

pressure is increasing to quickly.

A high pressure problem can be caused by a blockage. The solution is to identify where the pressure is too high by disconnecting one component at a time. For example:

Remove the column and attach a zero dead space connector. If the pressure is ok without the column you know it was the problem. You might be able to fix it by replacing a frit or reversing the dirrection (check the column documents) - Or you could try disconnect the tubing to the injector and If the pressure is still high the blockage must be in the pump.

Have you noticed a pressure increase resently before the error message?

[rhaefe]

Pinched tubings, clogged frits or check valves, salt precipitation in capillary lines or a clogged column are most likely causes for an over pressure error on the high pressure side.
Does your HP1090 have metering pumps or proportioning valves on the low pressure side. If memory serves me well, the metering version of the 1090 will display two pressure readings, one for the low pressure side (upstream the booster pump) and one for the high pressure side (down stream of booster pump passed the out let check valve. Pressures beyond specifications on either side can cause the system to shut down.

[thohry]

Possibly the pump's membrane is ruptured, or check valves malfunctioned.

[aman]

I have checked on the internet and it says there is a sieve found at the base of the booster pump which may need replacing. So I am going to try that.
Does anyone have a HP1090 operating manual before I start dismantling the machine??

Thanks Aman

[Slammy1]

HP tech support is very helpful on the. The flow path on the 1090 isn't so easy to decipher, at least the one I worked on.