What does the original equipment manufacturer's user manual say?
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"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Are you using the CO2 to purge the hydrogen during generator maintenance ?
I have designed many CO2 purge systems for hydrogen cooled generators, but have always used electric heaters. If your heater is oil fired, it will have a design fuel.
Like the others have said, RTFM.
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An obstacle is something you see when you take your eyes off the goal.