I'm trying to replace a faulty check/relief valve on an old Dionex-200 ASE (I'm posting here because this is basically an HPLC and I'm essentially looking for an HPLC check valve replacement). Thermo doesn't want to talk to me about figuring out which of their spare parts on the Unity Lab Services page might be the correct one here, as the instrument is now 'legacy'. Here's the situation:

There is a cartridge style check/relief valve (stops solvent going one way, allows gas to go the other with some PSI of 'crack pressure'). Pictures of the assembly and the cartridge are attached. The issue I'm having is the plumbing here (the t-union with the check valve attached) appears to be a setup used in the ASE-300 onward, whereas the ASE-200 typically had this union and valve integrated into the pressure transducer). I have found the part for the old, integrated check valve (a particular Kepner part, 2201D-3-5), but this doesn't look quite the same as the attached and I'm not sure it will seal into the assembly correctly.

Can anyone identify the cartridge in the attached photo, and/or identify a likely replacement option? I need a 1/16 HPLC cartridge style check valve (stainless, teflon seat, PEEK or teflon end seals), but with a crack pressure of (I think?) 5 PSI. I can't find any that specify a crack pressure (i.e. everything is just a check valve, not a check+relief) that aren't low pressure external plastic fittings.

Thanks!

Assembly (cylinder sticking out of bottom of t-union in center frame): https://drive.google.com/file/d/1F1042O ... sp=sharing

Cartridge:
https://drive.google.com/file/d/1DcUyrX ... sp=sharing

Matthew Wolhowe
University of Washington
School of Oceanography