Pressure is developing slowly in 5890 II plus

[faris]

Hi guys, What I have is listed:
1- safety shutdown before reaching the set point for the pressure and flow rate.
2- very slow flow rate elevating to the set point.
3- I was able to zero the PPE valve with the gas (H2) supply off and the column in the injection port is out.
4- as soon as I turn on the gas supply on and I put back the column in the injection port the flow rate is elevating by 0.2 mL/min from the zero. Same thing for the PPE pressure value.
5-gold seal and the washer underneath it has been changed. Also the ferrules in the column ends.
6- I was able to reach the set point for the flow and valve pressure by increasing manually 0.2 mL/min a time to 1 mL/min.

previously before this problem occur I noticed a decreasing in the flow rate from 1 mL/min to 0.991 mL/min at the end of the run when the oven temperature is 280 C and the pressure is high 17 psi.
thanks

[Peter Apps]

Step 1: check the whole system for leaks, using a leak seeker.

Peter

[thohry]

Just for you to consider. Long time ago, I used to use 5890, and I still remember that something happened just like you describe and the reason was a clog in the split valve. As I remember, it's an electronic control back pressure valve.

[Consumer Products Guy]

Or a clog in the weldment. Or a clog in the split VENT line; that includes the trap.

[faris]

[quote="Consumer Products Guy"]Or a clog in the weldment. Or a clog in the split VENT line; that includes the trap.[Yes, It was the weldment, Thanks for the help]