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GC 5890 II plus injector temperature drifting
Posted: Thu Aug 04, 2011 2:33 pm
by faris
Hi everyone, I change the sensor in the injector due to faulty temperature (the temperature was jumping around from -200 to +200 degree) . I put a used sensor form another GC. Now I have a drifting in the temperature by +_ 5 degree from the set point. The GC elevate the temperature of the injector to the set point and after that the temperature stays at the set point and later on starts to elevate gradually up to 5 degree from the set point, after that the temperature starts to drop below the set point gradually by 5 degree. and again elevating by 5 degree and dropping. did any one had the same problem and hope someone can help here. Please don't tell me it is the Main board because I just change it. Faris
Re: GC 5890 II plus injector temperature drifting
Posted: Thu Aug 04, 2011 4:57 pm
by Yama001
It is possible the insulation around the injector blocking was not put back in correctly. Often, you can fix this by poking some glass wool into any available spaces - look where the inlet comes through the oven. The proper fix is to take the inlet out again and put enough insulation around it, but that can be a real hassle to do again. Just try to be sure you dont have loose insulation flying around the oven or inlet once you are done.
If you still use the cups that surround the inlet in the oven, be sure to keep using them and replace any insulation that may have fallen out.
Re: GC 5890 II plus injector temperature drifting
Posted: Sun Aug 07, 2011 3:35 pm
by AICMM
faris,
Yamo001 comment about insulation cup is well founded. This is especially true if you injector is not hot enough relative to the oven temperature(s). The other thing you should ensure is that your RTD is snug in you heater block, not loose at all. If not, there is a lag time between heating and response and the controller cannot react quickly enough to maintain proper temperature.
Best regards,
AICMM
Re: GC 5890 II plus injector temperature drifting
Posted: Tue Aug 09, 2011 8:00 am
by DSP007
In 5890 a large portion of the capillary injector in a thermostat.
If you're an analysis for example in a temperature gradient 40-300C - the
at 40 C injector you strongly cooled, at 300 - is heated.
As this izzhedat. Standard on the protruding part of the injector is installed with glass wool cap. The injector is advisable to keep at a temperature greater than the temperature of analisis.