High Nitrogen After Replacing Carrier Gas Filter

Splitless mode -- you mean while the inlet is in purge off - waiting for injection?  Or when your system is in standby with the gas saver flow 20 ml/min?

What is your inlet pressure?  Column flow setpoint and column configuration?  How long since the inlet liner and O ring and the septum were replaced?  (and the septum not overtightened)

N2 levels crept up, but what about O2?   The Gas Clean filters are packaged in nitrogen and it can take significant time for it to be completely gone - like some days if the flows are low.  When I purge a new filter I let 400 ml/min rip for at least 20 to 30 minutes or so.

There's another process that will help, too. 

Disconnect the copper line at the back of the GC - after the trap, turn the gas supply flow on, put your gloved thumb over the exit to pressurize the plumbing and the gas clean trap, turn the gas off, thumb off to release the pressure, thumb on, gas on to pressurize, then repeat a number of times.  Those pressurize/depressurize cycles help release the nitrogen from the unswept pores in the filter material.  It’s not hard when the tank is near but annoying if it’s too far away. It's best for you to have a ball valve right before and after the trap to make that a bit easier.   

Splitless mode -- you mean while the inlet is in purge off - waiting for injection?  Or when your system is in standby with the gas saver flow 20 ml/min?

What is your inlet pressure?  Column flow setpoint and column configuration?  How long since the inlet liner and O ring and the septum were replaced?  (and the septum not overtightened)

N2 levels crept up, but what about O2?   The Gas Clean filters are packaged in nitrogen and it can take significant time for it to be completely gone - like some days if the flows are low.  When I purge a new filter I let 400 ml/min rip for at least 20 to 30 minutes or so.

There's another process that will help, too. 

Disconnect the copper line at the back of the GC - after the trap, turn the gas supply flow on, put your gloved thumb over the exit to pressurize the plumbing and the gas clean trap, turn the gas off, thumb off to release the pressure, thumb on, gas on to pressurize, then repeat a number of times.  Those pressurize/depressurize cycles help release the nitrogen from the unswept pores in the filter material.  It’s not hard when the tank is near but annoying if it’s too far away. It's best for you to have a ball valve right before and after the trap to make that a bit easier.