high pressure on agilent 1100

[lynzjm]

I've checked for older posts but can't seem to find a solution/suggestion.

We are running an Agilent 1100 and have tried to prime all 4 lines, but we're getting slowly climbing pressure on the system (no column attached) and we've put water, MeCN, buffer and various mixes down the lines indivudually and we manage to clear the pressure. If we try to put two lines on at once the pressure goes way up (>400bar) then one line that was previously clear will be blocked, then another one we've cleared will be blocked etc: There doesnt seem to be a pattern we can identify apart from lines going from clear to blocked!

We filter all our mobile phases, have cleaned all the lines and our column is working on another system so its not any of these either.

Would a problem with the actual pump or mixer valve cause very high pressure? Any tips on how to clean them or indeed investigate them in the "guts" of the machine without breaking it would be appreciated.

If any more information would help please ask any help is very welcome!

Thanks,
L x

[DSP007]

You have chance a " yang lady with a mischievous hands", which could inadvertently crush a pipe (by fanatical twisting strong nuts (steel) on Peek tube) ?

In addition, the dirt can drift from the sample injector (autosampler valve), the loss of salts in the pipes or tube corrosion.

IMHO Only one solve - to disconnect all the line and successively add system block (unit? as ALS, termostate , DAD) to a running pump for localization problem.

[warlock4761]

Have you recently changed the PTFE frit near the purge valve?

[Consumer Products Guy]

I've had high pressure due to particles in the autosampler rotor valve, small pieces of the rotor seal. A new seal and cleaning out solved that.

[LCbob]

Hi
Could be a precipitation problem with buffer falling out when you mix 2 lines.
Try cleaning all the lines with water and then run each individually, check pressure then 25% each compostion and check pressure.
Also change the frit in the purge valve.

[Durga malleswar]

hai

I thinkthe problem occurs only when the lines r blocked with buffer salts to clean wash the lines with hot water,
And the other reason for high pressure is due to the frits at the pump u can rectify this by changing the frit.

[lynzjm]

it was a dirty frit in the pump valve and a blocked piece of tubing leading to our detector that was causing the issue in the end! Thanks for your suggestions all - much appreciated
x