On Wed, 04 May 2011 10:43:28 -0400, Gogarty
wrote:

Here ya be:

"Moisture in a refrigeration system, directly or indirectly, is the cause of
most problems and complaints. First, moisture can cause freeze-up in a system.
Moisture is picked up by the refrigerant and transported through the
refrigerant line in a fine mist, with ice crystals forming at the point of
expansion."

That was my recent experience on the second of two systems that I
installed on our boat. After encountering symptoms similar to yours,
I ordered a new vacuum pump from Amazon for about $100 (cheaper than a
service call, and I already had a gauge set and can tap). I left the
vacuum pump running for 9 hours, checked to make sure that the system
was holding vacuum, and then recharged. It has been running fine ever
since.