[encantotom]

the air leaks i have seen the most in the plumbing bays are those solenoid valves that are for the main sewer dump and curb side dump. follow the airlines from the dump valves and you will see a black manifold. the internals of those valves are a rubber casing on a steel cylinder that slides back and forth and it ruptures. i have replaced several of mine.

usually it is leaking out of one of the regulator ports on the manifold.

i would check there first.

my two cents worth

tom