Chromatography Forum

I have an Agilent 1100 series HPLC with a bad degasser (goes red after initial 8 minutes), and I've determined that it's the solenoid that's leaking. Has anyone tried running without it, by just bypassing it with a union - i.e., is that solenoid actually necessary? I'm guessing that its function is to protect the vacuum pump but given the advanced age of this degasser, I hesitate to buy a $500 solenoid from Agilent for it.
Alternatively, if the solenoid is necessary, has anyone been able to find a cheaper off-the-shelf one that does the job?
Many thanks!

The function of the solenoid is to keep the vacuum , so you can not bypass it.
The vacuum pump runs until the vacuum upper limit is reached , then the solenoid closes to keep that vacuum and the pump stops.

Vacuum slowly decays from the vacuum chamber walls , when it reaches lower limit , solenoid opens and vacuum pump starts again.

I have an Agilent 1100 series HPLC with a bad degasser (goes red after initial 8 minutes), and I've determined that it's the solenoid that's leaking. Has anyone tried running without it, by just bypassing it with a union - i.e., is that solenoid actually necessary? I'm guessing that its function is to protect the vacuum pump but given the advanced age of this degasser, I hesitate to buy a $500 solenoid from Agilent for it.
Alternatively, if the solenoid is necessary, has anyone been able to find a cheaper off-the-shelf one that does the job?
Many thanks!

It is always worthwhile looking for any serial or part numbers on components like this and then doing an internet search for the number- a lot of manufacturers use standard components to build their stuff, and surprisingly often the code numbers take you to the component supplier's site.

Peter

Hello

Solenoid valve allows to switch pump off when vacuum is reached. However there are two switches on the small board where all plugs are (valve, pump, sensor).
You can change both switches to position "2" and pump will be running all the time. (it is possible if there is no other leaks like tubing or vacuum chamber)

Note: for new models there are no switches on board.

Regards

Tomasz Kubowicz

Biotech is having some retrofit kit for Agilent G1322A degasser, I'm a bit skeptic with just 480 uL of internal volume but it works in one of my HPLC

http://www.biotech.se/

The Biotech kit uses completely different parts than what are used in the original degasser. The pump, four vacuum chambers and controller are all different and the only parts that are re-used are the power supply and error indicating circuit from the original module. The solenoid is not part of the alternative design because the Biotech version uses a continously running vacuum pump and more porous Teflon membrane tubing (so it needs less volume to provide the same level of degassing as the original). There are pros and cons of the Biotech kit over the original design (depends on what types of methods you run and how much you abuse your system). The cost of the kit is high so best only if your entire degasser is trashed!

Are you sure its the solenoid? The #1 cause of red light on degasser is cracked tubing. Check the connections and replace/trim the tubing.
Seen dozens of red light degassers, 90% of time its tubing-cheap fix

The #1 cause of red light on degasser is cracked tubing.
Seen dozens of red light degassers, 90% of time its tubing-cheap fix

I fixed some using vacuum tubing from auto parts store.