Chad and I did a pressure test on TM2 tube Heater+(D) water line.I pressurized the D line with shop air from quick connectors(both ends) on service cap.chad applied bubble soap onto the D water block in SHC. The test started from 5psi,and increased 5psi each time to 40 psi. From 5 to 35 psi, no bubble has been found on water block. At 40 psi , bubble appeared from blind blank off seal , but not from soldering joints. Since the o-ring seal for the blank off is  vacuum seal , but not for pressurizing, It is understandable the seal could not hold 40 psi pressure air. No bubble had been found on the D water block soldering joints .See attachment pictures.