1050 pressure trace

[DJ]

I have a 1050 pump that is not software-controlled. I am getting rhythmic pressure fluctuations (60 +/- 10 bar).

Seems most of the diagnostics require a pressure trace. I am unable to do this, unless I can somehow rig my strip-chart recorder to the pump (I doubt I have the necessary cables).

Is there a trouble-shooting guide that doesn't require a pressure trace?

Besides failed pump seals, check valves, what else could cause these symptoms?

[Consumer Products Guy]

First of all: 1050 is a very good pump, and very similar to the 1100 and 1200 pumps as well, sharing several components.

Let's start with the basics. Isocratic and quaternary pumps use same pump, just quaternary has solvent mixing valve first (MCGV, multi chaneel gradient valve).

1. Which do you have?

2. If quaternary pump, are you de-gassing ALL solvents each day of use, even if you're only running two channels. This is IMPORTANT.

3. If quaternary pump, one thing to try is to premix your mobile phase and put all four inlet leads into one reservoir, purge all the channels, and then see if pressure stabilizes. This essentially makes the MCGV irrelevant. You may have an adapter that screws into the active inlet valve that allows you to just use one channel to alos bypass the MCGV.

4. Are your inlet frits clean? Maybe take them off temporarily, as a clogged one can create flow issues to the pump.

5. If you are using a 1050 degasser unit, remember that those have about 40 ml per channel of dead volume, so if you change a solvent type in a reservoir, you have to pump out 40 ml just to get the new solvent coming through.

6. A pressure test (plugging the pump outlet with a steel nut and running the pump to 400 bar so it shuts off) can help. See how long the pressure holds or how long it takes to drop 10 bar or so. There are specifications for maximum pressure drop per time.

That should be enough to get you started.

[LCbob]

Hi

Good advice above

Also if you have a strip recorder and a 1050 detector, the bnc connector on the detector can be used to connect to the back of the 1050 pump.