mobile phase pump out when hplc is not in use

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Dear all,

I would like to ask how come the hplc mobile phase will pump out when the hplc is not in use.

Yesterday, a 1 L newly prepared mobile phase was place at channel A.

The hplc was not in used.

However, the next day, the hplc mobile phase only left 300 ml.

No one is using the hplc and the instrument itself is not operating(no sound from the pump) when observe the next day. Furthermore, there is no error message found in the empower 3 from the message center.

I would like to know does the hplc activate pump and deactivate the pump by itself??

If not, what could be the possible reason?

Thank you in advance.
Leaking out through a partially open purge valve?
Major leak (hole) from the pump? The pump does not have to be on.
A sticky checkvalve, nicked seal or low flow rate assigned to a "shutdown" method could all be responsible as could failure to know whether appropriate initial conditions are in play at the end of a cleanout.
Thanks,
DR
Image
Was this a "one time" event or does it happen consistently? If it's a one-time, I wouldn't worry about it. Probably a partially opened purge valve as suggested above.

If it's a regular occurrence, the first thing I would do is to find out where the liquid is going. If it's in the waste reservoir and you have a column installed, then the odds are that the pump is waking up at some point during the night. If it's not getting to the waste reservoir you will have to check the system thoroughly to find where it *is* going. That should give you a good idea about where it's leaking.
-- Tom Jupille
LC Resources / Separation Science Associates
tjupille@lcresources.com
+ 1 (925) 297-5374
Was the column still in place in the system?

If you removed the column it could be possible for the flow to siphon through the system even if the pump is not moving. Most check valves prevent backward flow of pressurized mobile phase, but allow forward flow.

Also if you mobile phase bottles are pressurized with inert gas, it can push the mobile phase through the system and out any place that leaks. If you didn't find a puddle of fluid in or around the instrument then it must be going to waste.
The past is there to guide us into the future, not to dwell in.
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