This typ[e of unit does not have a conventional compressor that makes a noise, this is to make it "virtually" silent.
However many factors will affect the fridge.
Thetford recomend that in an ambient temperature of 15 to 25 degrees, the unit should be set to cooling level 3. If its hotter than this, the cooling level should be raised higher.
This should be normal for most people, and most situations. However, if you prefer the fridge to be cooler, its perfectly ok to raise the cooling level.
From the "off" situation, Thetford say you should allow 8 hours for it to reach temperature. Thats not to say that you cant put food in there earlier, but it will take longer for the unit to reach the right temperature, as the fridge is cooling the food and "itself" at the same time.
I would suggest that if you are planning a trip, the best thing is to start the fridge the day before, on 240v, with or without the food in it. This way it will have plenty of time to raech temperature.
I hope that makes sense
Can I ask you to take a moment and rate my response? Please use the smiley faces which you should now see. Please remember you are rating me personally, not the website or the problems you have had with this machine.
This will not close your question and you can still come back to me if you need more help