Chromatography Forum

Hello,

Our Agilent 1100 quaternary pump module (G1311A) is not working. The error message i get is "Pressure sensor not connected". I have talked to the Agilent technical support and they think that the damper might be down.

I am wondering if anybody else out here have come across the same problem and if so what was the remedy?

Regards,
Suresh

That depends. Are you one of those "guys with wrenches" that likes to fix your own hardware? If not, get a service engineer in there.

The pressure transducer is part of the pulse damper assembly. You probably don't want to attempt to repair it. If you are lucky, it is a loose connection where the transducer plugs into the electronics. If you are unlucky, you need either a new pulse damper assembly or a new electronics board.

the problem is that the transducer is defective. It generates a voltage, and that has drifted beyond the board's ability to "see" it. So, the board sees that the part is defective. You can replace it youself (if service is too $$$ or unavailable) Follow along in the user's manual. The part is rather expensive (> $1500) But, you relaly have no alternative.

Hello Joe and Mark,

Thanks for your replies. I did try taking the damper apart and re-plugging it back again to the board, but didn't work. I could order the part in and try fixing it myself, but what if the problem is in the HPM board and not in the damper??? I wouldn't be able to return the part back to agilent and that has left me with no choice but to call them in! And yes, you were right, the damper costs about 2200$ CDN.

I appreciate your replies, I atleast know the probable causes now to be ready to spend the big bucks..

Thanks again.
Suresh

I have work exclusively with Agilent pumps over the past 6 years. I have also replaced ~ 50 of the pulse damper assemblies.This is a "classic" symptom of the failure and replacing the pulse damper/transducer will fix it.

Hello Joe,

We just made the decision to procure the damper and change it ourselves. It was in most part as a result of your strong suggestion. Thanks for your suggestions again. I will reply back after we recieve the part and attempting to fix the problem.

Suresh

Joe and Suresh,

I also had this problem. If I remember, the high cost of the unit is due to the pulse damper, which is just a large stainless steel reservoir; it is the pressure sensor/transducer bit which fails, but since this is part of the same assembly, the whole thing must be replaced.

To me this seems extremely unfortunate- do other manufacturers also have this design? Also the failure rate of these things seems very high -is this a design fault? I've not heard of this problem on other manufacturers' instruments?

Joe/Suresh- what is your guess at the average lifetime of these components?

Dear Victor,

The LC 1100 we have is about 4 years old. This is only the second LC of that type i am working with. So, i am not in situation to suggest the "average" life time of the damper.

When i talked to the Agilent technical support, they did not waste anytime before they suggested that the damper might be down. Also, from the responses we are seeing in this forum and from Joe's experience, i believe this should be a series problem which Agilent should address.

I will be in PITTCON 2006 in march and will have an opportunity to talk to them directly. I am not too very informed to know the differences between the LC 1100 and the the LC 1200 which Agilent is planning to introduce during the conference next month. I hope they have made an attempt to fix this problem in their newer model.

Regards,
Suresh

This design, pressure transducer in the pulse damper, is not unique to Agilent, but theirs is the most popular example. There are good engineering reasons for doing it that way. The damper reservoir is filled with various materials, methanol or silicone are two common ones. Replacing the transducer entails refilling the reservoir. Doing that right takes special technique. I actually did this on an old Perkin-Elmer once, and it is quite hard, and the time wasted on my mistakes was worth the price of a new one. Only if I were trying to support a hundred instruments, and expected to do this regularly, would I invest the time in learning the technique.

I want to know any improvement applied to 1200 series from 1100 series. Could anyone give the information? Thank you.

I don't know about the 1200, but there are pumps that don't use pulse dampers at all. (Hint: I have a couple in my lab.) These dampers do reduce pulses, but they also increase the gradient delay volume. The internal volume depends on the backpressure; they don't work at all without backpressure.

We have 1050s and 1100s here, 6 total, and excess pump modules from our production facilities, and we've never encountered that issue HERE. At production, their Agilent systems were always under service contracts, our not.

We want purchase 1 unit of HPLC this year, maybe Agilent 1200 series. Our local distributor here does not supply the brochure about this series yet. So, I could not compare and find the improvement site. They offer USD 54,200 for Agilent 1200 series that contains quaternary pump with vacuum degasser, thermostatted column compartment, autosampler, and diode array detector.

Info about the 1200:

http://www.chem.agilent.com/Scripts/PCol.asp?lPage=181

Dear Joe and others,

Thanks very much for your advice and views. We replaced the damper ourself and the system is up and running. Thanks for saving us atleast 1000 $ CAD!!!

Best regards,
Suresh