My refrigerator seems to get more efficient the longer I run it. Am I missing something?

  1. I'm a newbie to refrigeration.
  2. The system is installed on a boat.
  3. The system is 22 years old.
  4. The condenser is cooled by circulating sea water.
  5. The system has a eutectic tank.
  6. 5 seconds after startup, watt meter indicates 1540 W.
  7. Over the next 60 minutes, the power consumption decreases by about 15 watts every minute.
  8. After an hour the consumption stabilizes at about 640 watts.
  9. The thermostat is set at maximum and I do not hear the compressor cycling on an off.


Can anyone offer an explanation as to why this system seems to run with less power the longer it runs?