Help for Balancing the valve pressure


I have a question about our GC 8860, which has been experiencing some problems since I changed the valve pressure.

Although it works well immediately after the change, if I don't use the GC for a few days, the first few runs produce larger peaks than usual in the standard gas. This can be seen in the attached picture.

Our GC system has two valves. I have balanced the pressure of valve 1 by matching the outlet gas pressure when the valve 1 is turned on and off.

For valve 2, it looks FID gas pressure is same when the valve 2 is turned on and off.

However, I think that the issue may be related to my change in valve 2.

I would appreciate any advice on how to handle this problem, and specifically how to position valve 2 correctly.

Thank you.

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