SP Scientific Freezemobile Series, Руководство оператора, Страница: 48 / 54

Appendix A: Troubleshooting VirTis Freezemobile 25L and 35L
38 Rev 005, 02/12
© SP Scientific 2012
Testing the Base Unit
If after performing the preceding tests the pump and the gage appear to function
properly, then it is likely that the leak is in the system. To locate a system leak in units
with smooth walled condensers, the base unit must be isolated from the manifold.
Suggested methods for isolating the base unit are as follows:

For units with “T” manifolds: Remove the manifold and insert a large rubber
stopper in its place.

For units with drum manifolds: Remove the acrylic disc on top and insert a
large rubber stopper into the opening.
Once the base is isolated, it can be tested for leaks in the condenser chamber. If the
base pulls down to an acceptable range, the leak is in the manifold. If the base fails to
pull down to an acceptable range, the leak is in the condenser.
Testing the Manifold
To test the manifold, remove all of the Quickseal® valves and block the ports with
stoppers. If the vacuum pulls properly, then it is likely that the source of the leak is one
or more of the Quickseal® valves. In this case, the Quickseal® valves should be taken
apart and inspected. Replace any white sections that have been scratched or
damaged.
Note: This procedure should also be performed on units with internal condenser coils.
Testing the Condenser
If you have isolated the vacuum leak to the chamber of your freeze dryer, the
following tests can be performed to locate the condenser leak.
1. Testing with Soap
a. A solution of liquid dish detergent and water can be applied with a brush
to all suspected leaks on the inside of the vacuum chamber. Pay special
attention to electrical feed throughs, the two shelf heat transfer lines, the
main 3” vacuum port and any welds on the chamber area; these are most
susceptible to leakage.
Note: The circumference around the back of the door flange is fully welded. The
rubber door gasket needs to be pulled back in order to brush this area with the
soap solution. The alcohol or acetone method may be more convenient for testing
this flange.
Once the solution is brushed on, the vacuum should be turned on for
approximately 30 seconds then shut off.
Note: If the vacuum is left on too long, the soap will start to bubble everywhere
and it will become difficult to detect the location of the leak.
A bright light should be used to locate the bubbles through the acrylic
door. The size of the bubbles will indicate the size of the leak. Larger
leaks produce larger bubbles.
When the leak is found, remove the insulation from the surrounding area
and test with soap once again from the outside of the chamber to confirm
the leak.