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7615 Control Troubleshooting & Spare Parts

Low control point: Note that when controlling from a higher pressure to a lower pressure, the lowest controllable pressure is is 400 psig (27 bar).

The most likely causes of poor control are the following:

  • air in the system
  • air in the DUT/UUT manifold
  • leaks
  • insufficient volume - min 50cc
  • control tuning
  • insufficient drive pressure


 Verify the following:
1.  Drive pressure is 90-110 psi

  • If drive pressure is too low the isolation valves will not stay closed.  
  • If the drive pressure is too high it will actuate the pressure relief valve.
  • Recommend 1/4" to 3/8" hose OD, the larger the better.

 2.  Minimum volume of 50cc connected to test port

  • The control tuning at the factory is done with 50cc volume.
  • Increasing volume or air in the system will increase control times and may affect control stability.

 3.  No air in the system


4.  Leak Test - DO NOT CHANGE TO MEASURE MODE AT FULL SCALE (MAX) PRESSURE - may blow burst disc

  • Leak test at around 90-95% FS.  When the controller is set to measure mode, there is displacement from the isolation valve closing and you will see the pressure increase by approximately 5% and this may cause the rupture of the burst disc if you are at full scale pressure.
  • To perform leak test, control to a pressure for about 2 minutes, go to measure mode, let pressure stabilize for about 5-10 minutes.  Take minimum of 60 seconds of data and ensure leak rate is better than 0.04%FS/minute


Additional Troubleshooting found at the following article


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