The most probable sources of gas leakage in the ProboStat are:

The enclosing tube O-ring seal: The remedy is first to tighten the ring a little. If necessary open it and inspect the O-ring for cracks or wear, clean and slightly grease the surfaces. We recommend silicon-free (all organic) vacuum grease in order not to contaminate hands, surfaces, alumina parts etc. with silicone which at high temperature inside the cell eventually will evaporate and form a thin SiO₂ layer on electrodes and surfaces.

The electrical feedthroughs: These are only mechanically sealed. If they become loose due to damage, they may leak, and sealing as described below or permanent replacement may become necessary. You may order new feedthroughs from us or send the base unit to us for repair.

In order to improve the sealing of the feedthroughs you may try the following:

Mount the base unit upside down. If possible, pump vacuum on the base unit and monitor the pressure if you can. Make a thin, readily flowing, solution of a polymer in a solvent, e.g. polyacrylate in ethyl acetate. Using a fine dispenser, apply a few drops of solution down into each feedthrough hole. If you hit a hole with a leak, the pressure will immediately drop, the polymer will get sucked into the leak, and seal it permanently upon drying. Allow drying of the solvent overnight.

O-rings in the quick-connects on the connector box: Perform maintenance and/or replace O-rings according to Swagelok procedures.

Cracks in the outer tube: Replace the tube.