Hi Fred--

I've had that valve get gunked up on our TC/EA.  But first, make sure 
the mass spec line  from the open split isn't hanging up when you take 
the dilution off.  Sometimes, instead of lowering down further into the 
split tube, it will catch and the capillary line will bend, which can 
even pull the end of that capillary line up so it starts to suck some 
air.  Then it's time to clean that out

Also note, if your EA goes into a "standby" mode, you may not have 
enough He flow through the system to keep the Conflo valve and open 
split properly flushed with He and you start to suck in some air.

Speaking of the valve, you should have He flowing out one of the splits 
on it at all times, and make sure both work.  If they don't, take them 
off and either rinse the lines out and/or replace them.  So far I 
haven't had to take the valve all the way out of the Conflo, just 
disconnecting the lines has tended to blow out any stuff that may be 
stuck in there.  If you end up taking all the He lines off and rinsing 
the valve with a little alcohol, it make take a little while before it's 
dry (exercise valve, mild heat gun) and you can hook up the outlet lines.

good luck....

take care

gerry

Fred Prahl wrote:
> We have been dealing for some weeks now with an unexplainable 'air' leak on
> our continuous flow EA-MS system that is intermittent and seems like it may
> be coming from our CONFLO III.  My current sense is that this 'leak' could
> only come from the flow diverter valve that is the first piece of business
> that effluent from our EA encounters upon entering the CONFLO III.
>
> This diverter is driven pneumatically.  When the system is in dilution mode,
> no problem is observed (but also there is no air pressure on the pneumatics
> for the flow diverter).  When the system is not in dilution mode, the
> problem shows up (and there is ~4bars of air pressure on the pneumatics). 
> But, the problem is not always there.  That really adds to the confusion.
>
> So, I have two questions:
>
> 1) can anyone provide me with a schematic of exactly how this flow diverter
> valve is constructed?
>
> 2) can anyone provide me with information about what can go wrong with the
> diverter valve and how that malfunction expresses itself with respect to the
> mass spec performance?
>
> To answer 1), We could take the flow diverter apart and find out how it is
> constructed but I don't feel comfortable doing that as we have no spare in
> hand (at the moment) and, in principle, I don't really like taking things
> apart blindly (unless there is no option).  And, to answer 2), the voice of
> experience is always comforting to me (perhaps a remnant of being read to as
> a child).  So, any experienced takers on this question?
>
> Any help / advice would be very much appreciated. Thanks in advance! 
>
>