I have a CIS4 PTV inlet from Gerstel on my Agilent 6890. Since I inherited this thing, it has been VERY difficult to get it to seal against the column adapter with the silver sealing ring, having to tighten it much more than I'd like. There was always a small carrier leak. Looking at the seal inside the adapter after removing it, it seems as though the silver ring wasn't quite large enough to perfectly cover the entire rim of the inlet's bottom fitting.

Looking closely at the bottom fitting, it seemed as though the rim had actually be FLARED OUTWARD a bit, presumably from years of overtightening. Assuming that's why it wasn't properly pressing on the silver ring, I bought a used PTV weldment and swapped it out. The new one clearly has its bottom fitting in better condition, no damage, no slight flare to the rim...

... and it still won't seal properly on a Restek column adapter and silver ring! No matter what I do there's a carrier leak.

Has anyone else run into issues with Restek CIS4 column adapters/silver seals not sealing on their PTV inlet? I'm wondering if there's slight, undocumented, generational differences between my (very old) CIS and newer versions of the same nominal part, and the replacement adapters/rings I'm getting from restek don't QUITE fit the older models?

Has anyone noticed a difference in fit between the Restek adapters/seals and the ones directly from Gerstel (via Agilent)?

I notice the silver rings have quite a bit of room to slide around inside the adapter before being clamped down on by the inlet, allowing them to get off center. Does anyone have a different source for a compatible silver sealing ring?