Chromatography Forum

Hi Everyone,

using GC7890A, suddenly front inlet pressure been increased to 134.5psi from set point pressure 13psi. Do not know what happened. Even tried to remove the gas supply, but still same 134.5psi. it supposed to read zero after disconnecting gas supply.
IF SOMEONE can advise what to do on it.

Hello

I think you have serious problem with EPC. I'm almost sure that pressure sensor on EPC is damaged.
If you've tried to switch off gas and it is still 134psi it is damaged.
You have 2 options:
1.Replaced EPC (quite expensive)
2.Try to fix it - good electronical engineer can fix pressure sensor. I've done it and I know it is possible and if someone knows how to do it you can save a lot of money.

Please note: Inlet EPC has specified pressure limits (for example 100 or 150psi) so make sure your gas source pressure is lower than EPC limit

Regards

Tomasz Kubowicz

we just had that problem. Tomasz is correct, you may need the EPC replaced.