Hello,

We are running a GasBenchII connected to a Thermo 253plus IRMS.

After opening the source for maintenance, we are getting a very high 
water signal of up to 30V when the needle valve to the Gasbench is open. 
The signal drops to about 2-3V when the inlet valve heater is switched 
off. Before we had a water background of about 1V. Also, Argon 
background is around twice to four times as high as usual but seems to 
unaffected by the heating. We checked the needle valve for leaks with 
Argon but it seems to be tight.

I read in an older post that the graphite ferrules tend to absorb water 
an then release it when heated.

Does anyone have had the same experience or found a way to avoid the 
problem? Will heating the ferrule with a heat gun work or just damage 
the needle vent? I don't know for how long the ferrule will keep on 
'sweating' or if it even will return to normal eventually.

Thanks,

Marvin


-- 
Marvin Bobrowski
Insitut für Umweltphysik
Universität Heidelberg
Im Neuenheimer Feld 229
69120 Heidelberg - Germany