Procedure for Priming GP 40 Pump for Dionex IC

Procedure for Priming GP 40 Pump for Dionex IC

Derek Hall

May 25, 2005

1. I'm going to try to describe this using the part name and location on the pump, and hopefully that will avoid any confusion. Having opened the door on the bottom panel of the pump, you see the two (black) pump heads - they have the two silver nuts holding each on, and on the top in the middle of these two pump heads is a block with tubing leads from the pump heads and this block has a black plastic screw which is screwed into the block during running - this block is your pressure transducer. You need to unscrew this screw about 4 turns out of the pressure transducer block (you may get small leak here if too loose, but its not a big deal). If its not loose enough, you'll get a high pressure alarm when you go to 'prime'. They made some nice improvements from the GP40 up to the 50 which I now have, but if memory serves, you should have a leur lock sticking out of another black block underneath the pump heads with a small metal lever on its top. If the leur lock isn't in already, screw it into the port there and then screw in the syringe.

2. In the software, make sure to uncheck the box marked 'connect' under the GP40 heading - I don't know if your software has this or not - if not, don't worry about it, we're going to do it manually too.

3. Unchecking the box will put the pump into 'direct control' mode rather than remote access locked. This can be done in the blue screen front panel on the pump itself. Arrow down to where it says 'remote' or something similar, and use the 'select up' or 'select down' arrow to change setting to 'direct control'.

4. Now, with the pressure transducer screw out ~4 turns, open the silver lever (which will allow flow through the leur lock into the syringe), and pull suction on the syringe. This will pull out any air bubbles inside the pump heads which would be causing it to miss. If the syringe fills and there's still more air coming out, just close the lever for a moment, empty the syringe and continue.

5. Once you've gotten all the air out of the pump heads and its a solid flow of eluent coming out, push the prime button to ge the pump moving and simultaneously push the eluent from the syringe back into the chamber you pulled air out of. Of course, don't put any air back into it. The syringe of eleunt is now pushing out any stuck air bubbles in the pump heads while its pumping. While still pushing on the syringe, close the lever which will stop permitting the flow frm the syringe. Let it run in 'prime' for a minute or two more. One of the telltale signs of air in there is a clicking in the pump, or a sudden drop in pressure on one side. Run in prime until it sounds smooth. Then close the lever, turn the pump to off, close the screw all the way in the pressure transducer, and run in normal fashion. Pump should have no pressure spikes or drops, and 'bad sounds' - yes, bad sounds. This process can be repeated until you're sure there's no air still in there. Once you're sure of that, we start looking elsewhere for how air is getting in, but we'll save that for a phone call.