Chromatography Forum

Hoping someone has some suggestions! I've had an API-2000 system up and running for the last couple of months. It hadn't been used in a while and initially gave me a few "bad source pump" messages in Analyst. These would go away when I'd disconnect the gas line in the rear of the MS and allow the pressure zero to reset. Earlier this week, the message would not go away so I ordered a replacement sensor. I replaced it and the the problem remains the same. Upon power up, I hear a click but I hear no gas flowing likely previously. I removed the entire Venturi pump assembly from the MS and checked all connections, the Venturi jet is not clogged. The electrical connections to the pressure sensor and solenoid valve seem to be OK, I confirmed DC power of 23 VDC at power up going into the solenoid and 5 VDC going to the pressure sensor. There is more than adequate nitrogen in the dewar and I've confirmed by removing each of the three gas feeds from the rear of the instrument.

Does anyone else think the problem is related to the solenoid controlling the gas flow into the Venturi pump? I pulled the solenoid apart, pulled a little on the spring, ensuring good contact. It appears to be getting good DC and I do hear a click at the solenoid valve upon power up, though. I just hear no flow and Analyst says that the source exhaust pump is OFF (sometimes it says BAD).

It seems the "fitting seal" going from the Teflon block to the pressure sensor is another suspect. I have it assembled as snug as possible - would I hear a leak if this was the problem? Also, the tube that leads from the Venturi system to the bottom of the ESI assembly is possibly another suspect. There is a teflon connector at the bottom that the gas line connects to that, no matter as much as I turn, doesn't ever really seem to tighten. However, it's always been this way and the system was working a week ago.

Any suggestions at this point would be greatly appreciated. Many thanks!!

-Aaron

I can sympathize with you.

I do not own a 2000, but have a 3000 and have used the 300. Both have a knob that you have to pull out to turn/adjust plus or minus exhaust gas flow, it takes a while for the system to catch up with the new gas flow so if this knob is on your 2000, then turn it a little (1/4 turn?) , wait a 30 seconds, turn some more... when the system says it is good push the knob back in to lock it (api 3000 and 300).

You also have to activate the instrument in analyst before you can do anything, and I forget if the exhaust flow is turned on or of when you activate your instrument profile.

Where are you located?

BTW, you DO need a minimum pressure/gas flow into what amounts to the "exhaust gas in" line. Not sure what it is on the 2000 but on the api 3000 I have my regulator set to 50 psi, then I adjust the exhaust flow control knob until a little above the minimum flow needed.

Sorry about my ignorance on what exists on the 2000, I hope you find a solution.

Alp