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Leakcheck the DU

From time to time it is a good idea to leak check the dilution unit and precool lines. If there is a leak from the DU or PC lines to the OVC mixutre can leak out and cause a serious problem. If mixture leaks into the OVC you need to recover the mixture from the OVC. (See [sec:serious.mixture]§sec:serious.mixture).

While the leakchecker is attached and running. Pressurize the DU with mixture up to $ \sim$ .8 bar:

  1. Open manual valve V14.
  2. Open V1,V5.
  3. Turn on the compressor and forepump.
  4. Toggle V9, until P2 reads about .8 bar. This may take some time as the mixture makes its way through the impedence.
  5. Close V9.

If you see a jump in the leak rate collect the mixture immediately. There is a leak in the DU.

To collect the mixture:

  1. Ensure V9 is closed.
  2. Close V1.
  3. Open V6.
  4. Open V4.
  5. When P3 gets below 1 mBar, turn on the turbo.

To leak check the precool lines leave the leakchecker attached and running when starting the precool. If you see a jump in the leakrate, empty the precool circuit immediately. There is a leak in the PC circuit.


next up previous contents
Next: Cooling Down Up: Leak Checking the OVC Previous: Disconnecting the Leak Checker   Contents
Jonathan Ouellet 2014-08-26