We own a RW 2 cryogenic refrigeration unit. I am attaching the manual of this unit to this email. Until very recently, our refrigeration unit had no problem in reaching temperatures as low as 27 K. However, a few weeks ago, after mounting the cold head on top of home-built support, we noticed a decrease in the performance of the refrigeration unit. The unit was no longer able to reach the accustomed 27 K. Instead, the lowest achievable temperature was about 70 K. After a few weeks of usage, the minimum achievable temperature has steadily increased. Right now we are only able to achieve temperatures higher than 125 K. According to the manual, this decrease in the performance of the unit is attributable either to a decrease in the Helium pressure or to a saturated oil adsorber. At the moment, the Helium pressure is exactly 14 bar, which is slightly lower than the minimum recommend pressure (15 bar). Our main concern is that the performance of the unit keeps decreasing with time. Our questions are the following: