Profile For Marc B.

Newbie here...

Would like to have a better understanding about the air brake low pressure system and test. On systems containing both a Primary and Secondary system, I assume each system has it's own separate path to the low pressure warning signal. So when testing, unless both systems leak down at the exact same rate, we're really only testing the side that leaks down the fastest to the signal point (60 psi). The system leaking down the slowest during the test never actually gets tested against the low pressure warning signal device. It seems to me that we are merely testing one of the two systems, and of course that the audible part of the warning system is functional. How will you ever know if, after a failure, that the other system will actually trigger the audible warning signal?

Or do I have it all wrong? Are there two low pressure signal devices (one for Primary, one for Secondary) each with warning tones at different frequencies?

Thanks.