Anyone like to conduct a fridge temp experiment to help me out PLEASE ?

Submitted: Wednesday, Nov 10, 2010 at 18:12

ThreadID: 82415 Views:4915 Replies:6 FollowUps:3

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JAZZY

Problems with Dometic 3 way fridge 90L RM2350

While we were away the fridge played up (on 240v - was fully operational however the fins at the interior back of the fridge were occassionally wet and dripping but other times they were cold and dry) but now we are home and the fridge is level and is working:

So, we put a thermometer in the fridge in 2 places for a couple of days and the findings are as follows (fridge empty):

Inside shelf in fridge:
0 degrees C

Inside fridge door, top shelf
12 degrees C

Fridge is running on 6 (on the front dial) 240V and the weather is by no means hot.

The top shelf in the door doesnt appear to be getting as cold as it used to so I am not sure if we need to have it fixed?

Also, on the way home (4 hours) we changed over to 12V and the fridge was not very cold when we arrived home - how successful is running a fridge via 12v plug connected to the car?

Was wondering if anyone would be able to conduct the same experiment so we can check to see what temp the door should be ?

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Reply By: Member - Ian W1 (QLD) - Wednesday, Nov 10, 2010 at 18:54

Wednesday, Nov 10, 2010 at 18:54

Hi Jazzy, would you have an Ultimate C/T?
I've got the Dometic 3 way and would be happy to try the experiment. I just put the Uti up today but haven't turned the fridge on yet...I guess it will take a couple of days to get the fridge temp stabilised, but will let you know the temp in mine. Cheers, Ian

AnswerID: 435582

Follow Up By: JAZZY - Wednesday, Nov 10, 2010 at 18:56

Wednesday, Nov 10, 2010 at 18:56

Thanks Ian, appreciate you rising to the challenge lol
The fridge is in our 16' poptop caravan.

FollowupID: 706759

Reply By: Member - Michael P (QLD) - Wednesday, Nov 10, 2010 at 19:10

Wednesday, Nov 10, 2010 at 19:10

Jazzy Hi,
A couple of things- 12V, 4 hrs is not a long time for the little element to get properly working. If you are opening the door to get a temp reading the air that rushes in will give you a false reading, ( I use a remote ENGEL dual temp fridge/ambient Thermometer,the fridge sender gives an accurate internal temp plus accurate inside the van)
To give you an example if I open the door for say 1-11/2 minutes the temp will rise about 4 degrees a couple of mins after closing the door.
Make sure the wiring etc from your car is up to the job Those fridges will draw approx 13 amps when pulling the temp down, Auto electricians appear expensive but a few dollars spent can save a lot of heartache.
Hope this is of some help.
Mike.

AnswerID: 435585

Reply By: Member - Ian W1 (QLD) - Wednesday, Nov 10, 2010 at 19:54

Wednesday, Nov 10, 2010 at 19:54

Hi Jazzy - OK...I've turned on my fridge (running on 240V) with one thermometer on the middle shelf of the fridge and the 2nd thermometer on the top shelf of the door. I'll leave it on overnight and check the temps in the morning. Expected to get down to about 16 degrees outside temp overnight.
Note that I've got a Dometic 3 way 90 litre but it's a model RM2355 not the RM2350, not sure of all the differences but mine doesn't have a dial for the temp adjustment, just push buttons to increase/decrease the temp so I've got it set to the 2nd coldest setting.
Both thermometers have an external readout so I won't have to open the fridge door.
Cheers, Ian

AnswerID: 435590

Follow Up By: Member - Ian W1 (QLD) - Thursday, Nov 11, 2010 at 09:22

Thursday, Nov 11, 2010 at 09:22

Hi Jazzy, checked the temps this morning...middle shelf of fridge is 0c degrees, top shelf of door is 5c degrees. The fridge is empty and no fan running. I've turned the fan on and will check again in a few hours. The outside temp is expected to get to 28 today
Cheers

FollowupID: 706816

Reply By: Member - Alan H (QLD) - Wednesday, Nov 10, 2010 at 20:15

Wednesday, Nov 10, 2010 at 20:15

I find that most fridges do not work well when empty. Cooling air is not their strong point so I tend to try to keep the fridge full even if this means putting empty container back in to take up space and reduce air volume.

Have seen some people put a computer fan inside the fridge to circulate the air so that most air washes across the coldest part of the fridge. I haven't done this but I have put a couple of fans on the back (outside) of the fridge to encourage more air flow across the heat exchanger when hot. I believed this helped recently when camped in 40 degree heat up near the gulf. Fans were put on the vent in the van wall.

Alan

AnswerID: 435593

Follow Up By: Hairs & Fysh - Wednesday, Nov 10, 2010 at 20:37

Wednesday, Nov 10, 2010 at 20:37

Hi Alan,
"fridges do not work well when empty. Cooling air is not their strong point"

Agree, I find my old two way(RM360) gets down to temp quicker and holds that temp better if I put a couple of two liter water containers in the door & a tray for ice in the freezer a day before and slowly pack it for the trip.
It took me awhile to wake up to this idea.
It also helps with getting a Chescold down to temp for traveling.
Manly used for drinks, but a few days before pack it with cold beer to start with.

Also agree with putting a computer fan to blow air across the cooling fins at the back. Haven't does this as yet, but it's one of the next jobs to do.

FollowupID: 706771

Reply By: Member - Boobook - Thursday, Nov 11, 2010 at 06:13

Thursday, Nov 11, 2010 at 06:13

There are a lot of threads on this subject but in summary your fridge will perform much much better if you

a)replace the 12v wiring in the van AND vehicle with at least 6AWG and make sure it is the only thing on that wire.

b)remove the fridge and pack all around the outside with insulation - one or two batts will be enough.

That should be enough to get your fridge down to 2-3 degrees on 12V in the fridge section.

Measure the voltage at the fridge. It is probably down to about 10.5v By using heavier wiring you can get 13v to it which will give you about 170watts of cooling verses only 110w. Thats 50% more coolong power.

Lastly you can easily remove the freezer door which will still allow you to freeze inside the freezer but make the fridge even colder.

Before I did these mods my fridge would be in the range of 8 to 12 degrees. I was going to swap it for a compressor fridge but now it works perfectly.

AnswerID: 435623