Chromatography Forum

Hi,

I have used an Agilent 1200 for quite some time now, both in reversed phase and normal phase. I take care to go through a mutually miscible solvent when converting back and forth.

Lately, whenever the pump runs, I hear a repetitive high pitched squeaking noise coming from the pump as it works. I have never heard this before, and I am now concerned. I'm wondering if anyone has any advice or experience with this? Time to change the seals?

Thank you!!!

Some of our 1050 and 1100 pumps squeak too. I've never worried about it, or linked to a failure or potential failure.

Ours do not have the seal wash option.

We get this quite often as well. Both on our 1100s and 1200s. Everyone always complains, but I've never be able to link it to any failing part. The systems we have with the seal wash option seem to quite down if we increase the frequency of the wash, so maybe its just the seal "drying out"?
I'm not sure what it means, but it happens more often at higher pressures (>150bar) than at low pressures.

I typically don't worry about noises unless the chromatography looks "weird".

I run two 1100s with G1311 pumps, one with a seal wash kit, and both occasionally make the squeaky sound. I have done preventative maintenance about 20 times and have never been able to pin it down...seals, pistons, whatever. The first time I heard it I was convinced something was wrong, but the chromatography looked fine.

It is annoying but I live with it.

As with the previous posters above, I've heard this problem when using Agilent 1100s and 1200s. The noise comes and goes. I don't notice any odd chromatographic effects, so I just disregard the squeaking.

If you are going between reverse and normal phase, you will need to switch to a different pump seal, it will take away the noise. Agilent sells a different material seal for normal phase solvents.

The pump head screws probably are a little bit too tight. Try to make some adjustments - release a little, tighten a little, etc. until the sound goes away and run the pressure and leak tests afterwards just to make sure it is still ok.

There are springs at the back of the pump head that the pistons push against. Engineers in the past have told me that these can rub against the block of metal they are mounted in and give the squeaking noise. You could try putting some teflon grease around these.

Unless you are having chromatographic problems or variable back pressures I would not worry.

Let me repeat again, you will need to change the pump seals that are specifically for the 1100 and 1200 series for running normal phase liquids, no loosening, tightening (adjustment) of any portion of the pump will help. The squeeking is caused by the rubbing of the seal against the sapphire piston.
Call Agilent and ask you will get the answer which is..... switch the seals.

giacomo56 - As I stated above, we get that squeak rather often (~once a month) on one of our Agilents (which one it is varies), and we NEVER run normal phase on them. Rarely do we even run buffers on them. I'm not trying to say you are wrong; I'm sure the wrong seal will cause a squeak as well, I'm just saying it isn't the only cause.

I agree with GregK. we have an 1100 and binary 1200. The agilent rep (a friend of mine) said the squeaking that occurs is nothing to worry about. It tends to happen more if you are using the binary pump and it may have something to do with resonance between the two pistons.
We have only ever run reverse-phase and have never linked this noise to a problem - in short, I wouldn't worry about it.

Right .. turn the pump on and look underneath the pumphead, you should be able to just see two gaps housing the moving springs and pistons.

Take a plastic pipette filled with water, insert the end gently into the front part of each gap and squirt a small amount of water into the gap...Viola! no squeak

Just dont go mad with the water, we are looking for a small squirt not a waterfall.

I'd like to report giacomo for spamming.

the solution is to loosen the pump head screws, as mentioned before. a quarter turn should suffice.

I tried the small squirt of water on the piston spring trick described above on my old 1050 and it worked right away.

I can't think of a potential downside except you need to protect the leak sensor with paper towels while you're doing it.

Thanks!

I tried the small squirt of water on the piston spring trick described above on my old 1050 and it worked right away.

I can't think of a potential downside except you need to protect the leak sensor with paper towels while you're doing it.

Thanks!

Just had an 1100 squeaking. Trick worked perfectly... I definitely recommend trying the water on the springs first before messing with the pump screws.