Thread: 3 way fridge operation okay?

These fridges aren't great on hot days, they work on temp difference eg a cool day (ambient air) and hot heat exchanger = big temp difference and fridge works well, as the temps get closer like on a hot day they suffer badly.
This is probably the same as the dometic ones in the jayco range. When I took my new jayco dove for its first trip on a 30 deg day the fridge would not go below 10 deg. Turning the fridge up higher will make it worse as it builds up more heat at the back of the fridge and if this heat can't get out the fridge loses efficiency. The only way to improve them as I did with mine was to install a baffle so that rising air must flow through the heat exchanger and not around it and I also installed 2 computer fans to increase the airflow through it on hot days. Now it works OK on 12v and very good on gas/240v, but I also have a compressor fridge in the car.
A search on the net will reveal solutions to improving them, also the standard wiring is too small they really need heavier gauge wiring for 12v too.
About an ammonia leak, shouldn't this leave a tell tale sign from the leak point?

Your title is correct, its a 3 way fridge, not a 2 way fridge as in the text, also ammonia is the refrigerant (sealed into the coils) the gas that makes it 3 way is regular LPG/propane.

3 way fridges use heat sources either LPG flames or electric elements to produce a change of state in the refrigerant and induce cold in the compartment and this system is subject to problems of having the coils rise evenly or they produce hot spots which can rupture with resultant loss of the ammonia.

In campers that stay in flat caravan parks or drive on flat highways, 3 way fridges work well, but in 4WD or off road campers leveling the fridge can be a problem and is why 2 way 240V /12V compressor fridges are preferred.

Most absorbtion type refrigerators I've worked on suffer from a lack of air flow over/through the boiler/condenser area and really suffer in a higher ambient/humidity.

A supplementary fan or two to draw the air through the condenser area often really helps performance.

BTW, if any refrigerant (a mix of ammonia, bromine and water) ever leaked you'd really know about it, ammonia isn't shy.

[edit] It was only pointed out to me recently that a lot of caravan builders in Australia don't fit the tropical rated Dometics either, which is negligent for this countries summers.

Originally Posted by rick130

...BTW, if any refrigerant (a mix of ammonia, bromine and water) ever leaked you'd really know about it, ammonia isn't shy.

Absolutely and you have to air the camper for days and throw everything in the fridge away.

Well that is my experience and hence my dislike for 3 ways in 4WD.

Thanks all.

Pawl , do you have any pics of your upgrades.

Lotsa , are you saying the the fridge has 2 electric elements a 240v and a 12v,

The van does have a 240/12v adaptor/charger and I think the options on the switch are only AC or Gas.

when mine started playing up i tried all sorts of things people suggested ended up throwing it out and replaced it with a engel

Originally Posted by land864

Thanks all.

Pawl , do you have any pics of your upgrades.

Lotsa , are you saying the the fridge has 2 electric elements a 240v and a 12v,

The van does have a 240/12v adaptor/charger and I think the options on the switch are only AC or Gas.

No dependant on model they usually have 2 inputs 12-24VDC and 110-240V AC and an inverter/rectifier to supply the DC current for a single element. Although some models of both gas/electric and electric compressor do require an external inverter/rectifier. It is just your thread had a different title to that in your text so assumed 3way.

Originally Posted by richard4u2

when mine started playing up i tried all sorts of things people suggested ended up throwing it out and replaced it with a engel

EXACTLY!!

and yes,, it would appear none of the current Dometics are rated for anything like our summers