Im working on an Endress Hauser strap on ultrasonic flow meter Prosonic 500 .Its set up in a 8 inch cement painted pipe. I get 0 dbs or very low signal, when the pipe is empty and its causing an alarm code f104. It should just be 0 gpm in green. I measure 21.97 ma fault condition.I have it hooked up 2 Traverse with 2 sensors at 3 o clock linear. when the pipe is running i get correct reading and my db jump to 27 db. has anybody seen this? Any help will be greatly appreciated