Dometic 3 Way Fridge

[timsgonecamping]

Hi
I think this is probably a question for people who have/had Cub campers.
I'm after a bit of feedback on your experience with the 60L 3 way upright Dometic fridge that Cub fit in their Supamatic campers.
It seems a bit useless.
So I'm wondering whether I have a dud or they generally aren't much good.

On gas it seems to take at least a few hours to get down to any sort of workable temperature.
If the day gets a bit warm, say 30 degrees in the tent, then the internal fridge temperature tends to climb up over 10 degrees.
Adding fans blowing onto the condensers helps a little but there is no way I would trust it to keep the meat or the milk cold.
So it ends up being a drinks fridge and even then it's a bit average.
I have to transfer the day's beer supplies to the ARB fridge in the car to make sure I get a cold one.

Talking to Barry at Colo he is quit happy with his 90L version in his Spacevan however the larger version of this fridge may be more efficient.

I have read a bit on the forums that say that these type of fridges are only good for 25 degrees below ambient however mine doesn't seem to even do that.

So I am trying to figure out whether to have it looked at or to just rip it out and put a cupboard in its place.

Tim

[thommo19]

Hi Tim
We have the same fridge and a 47ltr ARB fridge on the draw bar.
Our method is to run the internal fridge the night before we leave and get it to a good temp. Once on the road we switch to 12v.
When camped we try to continue to run on 12v ,but depends on the sun/solar, if not switch to gas. We only use the fridge for day use as in milk, bread, butter, fruit etc. We find it works fine, the internal temp. of the camper does make it work harder, but is still effective .We transfer frozen stuff into the fridge in the morning that we require in the evening ,it all helps .
A bit long winded reply but hope it helps.
Jeff

[robcaz]

Hi Tim,

The fridge needs to be set up level to run its best. Use a spirit level on the fridge & then align a bubble level on your A frame to suit, set in a bed of 'no more nails' etc.

Because the fridge draws 10amps or more on 12volt a common problem is under sized wiring, that is voltage drop will be more or less running the fridge on a flat battery. You should get a good cooling result using a suitable sized cable from your camper batteries to the fridge using Redarc's cable size calculator while your Redarc BCDC1225 will look after keeping up with the draw from the batteries while driving.

3way fridges can get a vapour lock in the tubing at the back of the fridge, turning the fridge upsidedown overnight to clear the lock can help at times.

[timsgonecamping]

Thanks Jeff
It certainly sounds like you have had a better experience than me with this fridge so maybe I do have a problem.

I've replaced the wiring to the fridge however it's still not much good on 12V.
When the camper is closed up there is very little space for airflow so it tends to heat up like an oven. I don't think the low side vent on the camper is very effective.
So I was going with the idea that the fridge should perform at its best on gas with the camper open (and level) but even then it's very average.
I may well have vapour lock as Rob suggests however the fridge is bolted to the camper so hard to pick up and turn over.
Maybe Rob can demonstrate tipping the camper over at the next meet

Tim

[robcaz]

Hi Tim,

I would be only too pleased to show you how to tip your camper over at the next meet

You may pick up a few ideas on how to get a better air flow across the back of your fridge in Collyn's article http://www.caravanandmotorhomebooks.com ... idges.html

[spoton5]

Copy & paste of my answer from Yahoo

Where does one start
I have one installed in my 2009 Cub Spacematic
I was having all the trouble in the world trying to keep something cold from this fridge
First I put it in for a service which confirmed the fridge worked well on the bench in all 3 types of power of Gas, 12v & 240v
In Summary of my research
It is illegal to run the fridge on GAS while travelling, Fire risk
The fridge needs to be very level to work properly, especially on gas
Need 12v to be ON to start the fridge on Gas, ( 12v starter )
Freezer will not freeze items, but will keep items frozen
Will get down to temp better when fidge is full
Best to start fridge at least 24hrs before trip to get fridge cold, using 240v
Modifications I performed on my fridge to work better
1. Changed all the 12v wiring on my fridge from approx. 2mm wire to 4mm.
This was to reduce the voltage drop across the length of wiring from battery to fridge, need at least 12v at fridge for it work properly
Put a Anderson plug in place behing fridge in the new wiring ( yes overkill ) no voltage drop & can easily remove fridge with a 20amp fuse at fuse panel
2. On the exhaust pipe which is mounted to send the heat to the outside of camper I have wrapped with exhaust wrap,
brought off ebay, this is to keep the heat inside the pipe & not at the back of the fridge, amazing how much heat these fridges produce
3. Mounted a computer fan at the back of the fridge, this is mounted horizontal under the condensor & draws the cold air from the vent
which is mounted near the floor behind the fridge. Computer fan uses 0.2amp/hr I paid $5 for a second hand unit from loccal computer shop
I have a seperate switch for this fan which is mounted on the front panel of the fridge.
4. Mounted a Digital LCD Temperature gauge on the front of the fridgewith probe cable tied inside center of fridge, under $5 delivered off ebay, brought 2 one as a spare Now runs at zero on a 30°c day.
Temp. Amazing how quick the temp goes up when door is open
On 12v fridge can draw up to 11.5 ah on start up, Once fridge is down to temp it is pulling 4.7ah, before mods was using 8.5ah at 30°c
Hope this helps & regards Peter

[timsgonecamping]

Just a follow-up on this.
Removed the fridge and took it to a Dometic agent to test.
They ran it on 240V and graphed the resultant temperature gradient.
It dithered around at ambient for the first hour and then a very nice curve down to 2 degrees over the next hour and a half which is where it stayed even when it was put in the sunshine.
So it seems the fridge is as good as it gets on a 3 way.
He did suggest putting a vent in the top panel and sealing off the air gap under the top to stop hot air from the condenser getting into the air gap between the fridge and the metal case.
He also said only one computer fan mounted horizontally under the condenser would help.
He said that the three I was using may be too much and may be affecting the cycle.
He also wasn't keen on my idea of putting a small fan in the freezer section to blow some cold out from there into the general fridge area. Said it would make that area too warm and affect the colling from the fins at the back of the fridge.

So I've cut in a vent on the top and sealed the air gap and changed the fan to horizontal.
I was away this weekend but couldn't get it very level. However it was running at about 3 degrees after a few hours. However ambient was only around 20 degrees so not a proper test.
I'll have to wait for the next trip to see what happens.
Thanks for all of the feedback on your experience with these.
Tim

[spoton5]

Hi Tim

The next thing to do is the Exhaust wrap
The idea of the wrap is to keep the heat inside the pipe, works like installation
Before I put the wrap on the exhaust pipe the best place to dry a wet towel was above the fridge
These little fridges throw out so much heat to work, esecially when camper is closed up travelling to camp etc, like a oven when you open camper up
I ordered my wrap off ebay, was about $15 delivered, 1m of wrap & 6 s/steel ties
The Exhaust pipe is only about 300mm long, remove fridge & just wrap the pipe a couple of times, just like putting handlebar tape on a push bike.
At the start, wrap a couple of times & then put a s/steel tie to hold in place, put a fair bit of pressure on wrap to keep tight
I will post some photos next week (will open camper up next weekend)

Peter

[timsgonecamping]

Thanks Peter
So is the wrap mainly to try to reduce the heating up of the camper while it is closed?

I was undecided about insulating the exhaust pipe (except to stop burning the toes) when the camper is open.
I thought it may be good to let as much heat escape via the exhaust pipe as possible even if some of it was into the camper itself.
Not ideal on a hot night though.
I look forward to the pictures when you get to it.
Tim

[spoton5]

Exhaust Wrap

The main reason to put the wrap on the exhaust is to contain the heat INSIDE the exhaust pipe, which is piped to go outside the camper
The exhaust pipe is approx 250mm long on a angle of about 30°, hot air rises to outside the camper
The fridge then works so much better because the new installed computer fan is sucking the ambient air from the bottom of fridge air vent, not the mixed air ( heat from exhaust & the ambient ) especially when shut up traveling to & from camp sites

The Photo of the front of the fridge shows the new Temperature gauge (under $5 on ebay) runs the cable throught the top door seal & cable tied the temp probe in the center of fridge & a new switch on the right which controls the computer fan



Shows the exhaust wrap, has 2 layers over the Exhaust pipe