[C320-list] burping pss seal? direction

[LOCALJG at aol.com]

I have one of those seals and was wondering why one would burp it?  Is it, 
"because you can" or is there a reason for burping?  
 
I have owned the 320 since April of 2010 and have a lot to learn.  Hence 
the question. 
 
Thanks,  
 
John G. 
#329