Anders and I found a low frequency issue(13hz only) on TCS TGHT flow sensor when doing TM4 conditioning. By trouble shooting, We found the module water lines are good. the restriction cause this problem in on TCS supply or return water lines to TGHT.  I switched TGHT lines with MSP water lines. The wheel frequency on TGHT is 67.0hz which is pretty high. Now, MSP is using the original TGHT water line(flow sensor frequency 13hz). Flow sensors and thermocouples are switched as well so no control system change is needed on epic page. Everything are re-labeled in TH.  With less brazing joints closing to heater source, the MSP line should be ok. By further troubleshooting this issue, I think the problem on this low flow sensor frequency problem is on those 1/2" Parker gray water lines inside that big  6" white pipe.  See attachments. The lines are are twisted, and could be squeezed in my view. Since everything is enclosed in that big pipe, It is hard to tell where the lines are squeezed and cause this restriction. Comparing to an open guide chase, this round pipe makes everything  difficult. Hard to trouble shooting , hard to remove lines or add new lines. It only looks beautiful. I tried all I can do, But, I have no quick solution to solve this problem permanently.  Maybe, Rob walker and his technicians has better skill or more strength on removing old lines, or adding new lines to solve the problem.