Beckman Coulter Optima™ L-100XP Temperature Drifts Rapidly

The fuge has been working properly until today.  We set up the temp at 18 degrees.  10 min after the start, the vacuum dropped to 100.  Then suddenly the temperature spiked to 43.4 degrees.  After that the temperature started to drift from 43.4 to 6.7 back and forth rapidly.  Now the vacuum is 1 micron but the temperature cannot hold and is still drifting.  Any suggestions?