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GE 6B Bottle Test
Question on GE6B SRV/GCV leak test.

We have 2 GE Frame 6B dual fuel DLN1 combustion turbines with MARK V controls. Question I have, can some one explain what takes place during the "bottle" test of the SRV and the GCV? We have a vent valve between the two valves and it operates correctly. We do not get an alarm at this time. We did previously and this was because of leaking on the SRV. It was repaired, alarm gone. Our SRV and GCV are two separate valves. Main concern is the GCV getting tested for this test or is the concern leakage by the SRV?

There are two gas valve tests, and they're commonly confused.

The idea of THE bottle test is to check the integrity of both the SRV and GCV, by admitting some fuel gas pressure into the P2 (intervalve) cavity after closing the vent valve (20VG-1) and monitoring it to see it if drops--which would indicate a problem with either the vent valve or the GCV. (Of course if the pressure increases, then that's a problem with the SRV.) By capturing a pressure between the two valves (in a sense, "bottling" the pressure) and monitoring it to see if it changes by some amount, the test is checking the integrity of both the SRV and GCV (presuming 20VG-1 is working correctly--and it's just an open/close valve which doesn't usually fail, but does from time to time.

So, depending on whether the pressure decreases or increases (again--presuming 20VG-1 is working correctly) one can determine if there's a problem with the GCV or SRV, respectively.

If I recall correctly, the other test simply closes 20VG-1 and checks to see if the pressure builds up while the SRV is closed. If the GCV is holding (not passing; not leaking) and the P2 pressure increases, then there's a problem with the SRV.

Again, the two tests are mistakenly confused and both are referred to as "bottle tests." I think each test has a comment in the sequencing or application code to indicate which is which.

Hope this helps!

By 6bturbinetech on 10 April, 2017 - 7:51 am

Thanks for the response, helped a great deal. Follow up question, is this test only performed on start up? Any testing on shutdown?

Test is run at start-up and shut down every time.

Drop me an Email to bbobjohnston@gmail.com and I can send you a document on the Gas Leak Test.