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Post Info TOPIC: insulating dometic fridge
2weis


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insulating dometic fridge
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I want to improve the performance of my fridge (dometic rm2553 ) and I was able to get some silver foil backed earthwool insulation

when I install it do I put the foil to the fridge or to the cabinet side

is the foil conductive if it touches wiring (there is some 12v switches on 1 side)

I have already installed 2 computer fans and have a shade but would like to improve the fridge operation as much as possible

thanks in advance

brian

 



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PeterD


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You can only apply the insulation to the top and the side. If your fridge has been installed correctly there will be no room between the sides and the cabinet. There should be next to no gap there. Do not put any at the back, that will alter the airflow around the heat exchangers. The foil will probably be just aluminium and therefore conductive, keep it away from live terminals..

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PeterD
Nissan Navara D23 diesel auto, Spaceland pop-top
Retired radio and electronics technician.
NSW Central Coast.

 
2weis


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peter
my fridge has no insulation I can detect
I want to insulate the top and sides
I will make sure any live terminals are insulate and I will allow as much room around them as I can
any suggestion as to which way to face the foil ??
brian

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Diane1


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Foil CONDUCTIVE...... Read up on air spaces and those fridges, some need less than is provided around them, Specialy at rear. the actual airflow is part of cooling cycle. Unfortunately those things are basically, at best. A fridge once North of Tassie. As long as sun don,t come out. What a lot do is swap out for a Waeco type of same size and perfect even in the Simpson with solar. Or keep and make do, while also adding a portable Waeco unit for freezing (I have 80ltr with this van.)

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Aus-Kiwi


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I have used the thin foam used on steel roofs and under floating floors .

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C00P


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If you were installing this type of insulation in the ceiling of a house, the shiny foil side would face down. The purpose of the foil is to reduce radiant heat and shiny surfaces radiate little heat. I have used foil only insulation to insulate a large shed and the difference once the foil was installed was amazing.Facing the foil down seemed counter-intuitive to me as I thought the purpose of the foil was to reflect radiant heat, but this is not the case.
So, if you want to use this insulation to reduce radiant heat coming into the fridge, then the shiny side would be placed near the fridge. For this to work, there has to be an air gap between the foil and the fridge. Exactly how you would arrange this in such an installation is beyond me,and you might be better off consulting the fridge manufacturer for advice on how best to insulate your fridge.
Cheers

C00P



-- Edited by C00P on Saturday 4th of February 2017 03:11:24 PM

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2weis


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thanks for the advice
I was able to remove the foil so that removed the possibility of shorting
I insulated both sides as best as I could , at least it will be better than before
I was able to put 2 layers on top and fashion a curved hood to direct airflow out the top vent
via the fans
just a tip for anyone working with this type of insulation wear a long sleeve shirt
brian


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Aus-Kiwi


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The insulation I was using doesn't contain fibreglass . I itch for days with fibreglass !!



-- Edited by Aus-Kiwi on Saturday 4th of February 2017 06:26:43 PM

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Dick0


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Hi Brian,

I tackled a similar job on my Jayco Freedom.

I removed the Dometic fridge from the cavity to check the amount of clearance inside and to see if any efficiency improvements could be made.

The initial inspection revealed gaps in all the corners of the cavity, some 1cm wide, and I sealed them with clear gutter silicone which then ensured that only air from the lower vent would exhaust through the top vent.

The fridge already had a thin layer of aluminium insulation stuck to the sides and rear. I obtained from Bunnings some thin floating floor insulation which also had a thin layer of gold aluminium insulation on one side.

I taped this insulation to the sides, top and back, leaving the cooling fins exposed. I installed two 120mm fans at the top vent and a temperature controller inside the van. A temperature probe/sensor I inserted between the cooling fins at the rear of the fridge.

I set the fans cut in temp at 40C and cut out temp at 35C. No other air than that entering through the lower vent can enter the cavity. The air drawn in can only pass past the fins which are about 1cm from the rear of the cavity.

In hot weather I fit a shade screen over the inlet/outlet vents.

I have increased the efficiency of the fridge greatly. I run the fridge on gas as I free camp and have no problem keeping the fridge temp at about 5C in the hottest weather...eg, in 35C weather with fridge thermostat set at setting 4 the fridge holds a temp of around 5C inside.

I also installed a temperature sensor inside the fridge and can view the current internal temp at any time, and can therefore adjust the fridge thermostat up or down as required.

Hope this helps in some way.



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Cheers, Richard (Dick0)

"Home is where the Den is parked, Designer Orchid Special towed by Jeep Grand Cherokee Limited"

"4x250W solar panels, Epever 80A charger and 3x135Ah Voltax Prismatic LiFePO4 Batteries".
C00P


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I also use an indoor/outdoor thermometer I got from Jaycar to monitor the fridge temp. I was quite surprised to find that the "outdoor" module (which sits inside the fridge) communicates happily with the main unit (the "indoor" module) via Bluetooth, allowing the "indoor" module to display temps inside and outside the fridge.
Still working on improving my setup- the original installation has the top of the top vent sitting about 3" below the top of the outlet duct...no

C00P



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2weis


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thanks for the replies DickO and COOP
as I have said I have insulated the top and sides as good as I can without taking the fridge out
I know I would be able to do a better insulation if I did take it out, will wait and see
I have been takint tamp readings with a sidewinder dual zone thermometer and a multi meter with a probe
I am reading inside van temp inside fridge temp and a glass of water sitting on a shelf 4 times a day
I want to give it a couple of more days before I come to any conclusions
brian

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C00P


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Good approach.Collecting that sort of data should give you a pretty good idea if you are making progress. Plot outside temp. against inside temp. to see how they relate. Then make a change to the setup and re-plot after a few more days' data. If the graph changes so that the temp difference between outside and inside increases, then you are winning.
I'll have to do the same thing myself.
Curious about why you are using a glass of water, tho'?
Regards

C00P

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PeterD


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I should have stated im my previous reply that if the fridge has not been ventilated properly you are only fiddling around the edges of your problem. Download this document - Optimal installation of Dometic 3 Way absorption refrigerators in caravans, - For starters you have a 150 l fridge and I bet the vents they used were only the ones for fridges up to 100 l. Then have a look at the position of the top vent, pounds to peanuts it was mounted too low in relation to the top fins.



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PeterD
Nissan Navara D23 diesel auto, Spaceland pop-top
Retired radio and electronics technician.
NSW Central Coast.

 
2weis


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PeterD
yes you are right it is only fitted as per the 100 l instructions
as it is now an 8 year old van it will be hard to alter vent installation
I will have the results of my tests by Friday and I will see what improvements I have made
with insulating and makin a deflector plate anf the fan fittments
brian

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