Best practice for cooling fridge on propane.

[CruizinDux]

We generally load the TT except the refer the night before. That morning when picking up the TT at storage, I fire the fridge on gas and load 3-4 frozen 1/2 gal milk cartons. By the time I get hitched up and home it is well on the way to <40. By the time we're ready to leave (total time from fre to departure about 90 minutes) I'm <40. I remove the milk cartons if I'm tight on space, load the refer including a small bag of cocktail cubes and hit the road. At the first rest stop I check the ice cubes and refer temp but have never had a problem. Generally it's around 33/34, the beer is cold and ice still stable.

I had saved an old U-tube video that is no longer operational re replacing the thermistor. Seems you could check resistance itself, maybe dometic could provide a normal resistance #.

However I found this link from a separate vendor, which includes an adjustable thermistor...vs the up to cold setting.

https://www.snip-the-tip.com/cgi-bin/articca.cgi
the link also has other links re diagnosis.

I'd move the thermistor up all they way (should that not be the current setting/location) and test at home first...then consider replacement.

Please let us know your resolution.

Bob

[GM Airstream]

Hmmm.. well first... we put a gallon of water in the refrig section and 3 of the smaller water bottles in the freezer.. and turn 'er on... wait till the water in the freezer gets to ice and the gallon of water in the ref get to about 38 deg... remove water and replace with items already cold from home refrig...

A word of caution... I had a negative experiance with dometic... refrig... not because of the company but rather it was the PO that ran it off level...

Its is imperative that you make sure the refrig is level... when you fire 'er up... and keep it that way when stationary... if not.. you get to experiance the thrill of changing out the the cooling unit... and replace'n it with a new /overhauled one.. (or buying a new refrig that doesn't ever fit right back in)
What happens is the boiler tube down above the burner assbly... will cook and cause the cromate in the solution to crystalize... (its in their to keep the refrig gas's etc from rusting the tubing inside out...)
But, ... as time goes on... indeed the refrig will start losing effecency from the day it was made... even if you keep it absoly' level... however, most will outlast the RV's life...
How to tell is to keep track of the refrig operation.. i.e cooling vs interior/exterior temps. is to keep notes on what the outside temp is... to what the refrig comes in at with the control setting the same.

It is true that the refrig send the cooling to the freezer first.. so if the freezer is still doing its thing.. but the refrig section is not getting down to 38 deg when the door is kept closed... then you can tell if the refrig is suffering from age/neglict after making sure its always kept level. (key point here is LEVEL)

Now with the temp control around 3-4 at all uses... and outside temp of around 70 deg...(above 100 the refrig starts to quit working because of the physics of the beast)

If the freezer is getting down to freezing but the refrig section is not getting down and holding in the 40's or 50"s then its starting to show it age... as the capacity to cool is starting to fall off...

It is not the freezer temp that you want are conserned with... as the gas enters it first... and then trickles down to the refrig section... it is the refrig section that determines how effecent the unit is working.

If its not getting down to the 38 deg mark.. then you should start looking at the service of the refrig.... I.E check for dirt/bird nest/rat nests that might be blocking the cooling units back.
Also.. you want to insure that the propane pressure is correct... (checking the stove burners is a good way) or the electrical element is getting the voltage...as again low voltage through a extension cord is poss too... (as it runs from their to over yonder)
Once you have checked all these items... cleaned and serviced the unit.. and its still not getting cold in the refrig section... they its time to start looking for a new cooling unit...

By the way... dometic engineers have said that if the refrg is off level...it only takes 30 min or so to damage the cooling unit.. and their is no easy fix once damaged.. life is over... so you want to make sure that when you stop in for lunch on that parking lot that is not level.. and you leave the refig runn'n on propane etc... you check level.. or else things get nasty shortly before you finish you lunch.

Better to have it off than damage it... i.e that is what the frozen bottles of water are for... when your traveling...

Hope this helps ya to keep yours for a long long time...

the adventure contenues...
G.M>

[OTRA15]

Originally Posted by GM Airstream

Hmmm.. well first... we put a gallon of water in the refrig section and 3 of the smaller water bottles in the freezer.. and turn 'er on... wait till the water in the freezer gets to ice and the gallon of water in the ref get to about 38 deg... remove water and replace with items already cold from home refrig...
. . .

Why do you put warm items in the fridge/freezer and get them colder? Isn't that a waste of energy, either propane or electric?

Why not put something already frozen in each compartment, and wait about an hour until each compartment registers the correct temp on a thermostat inside?

Seems simpler, less time-consuming and more energy efficient IMO.

Cheers,

Peter

[GM Airstream]

Originally Posted by OTRA15

Why do you put warm items in the fridge/freezer and get them colder? Isn't that a waste of energy, either propane or electric?

Why not put something already frozen in each compartment, and wait about an hour until each compartment registers the correct temp on a thermostat inside?

Seems simpler, less time-consuming and more energy efficient IMO.

Cheers,

Peter

Well...
if you put frozen things in the freezer... not much happens because the freezer doesn't have a thermostat...

so once the freezing section gets cold... the fluid pass by gravity to the lower compartment...and starts drawing heat out of it...

by putting frozen things in the freezer... you don't save much of any time or energy...

however,
PUtting frozen items in the refrig section would send a message to the theromostat that is located in the refrig section.... that the whole refrig is cold and so will shut down/cycle the refrig cooling unit...

and may not cool the whole refrig.. which is not what your wanting....

Thus you want to keep the refrig section above the thermostat setting so that the refrig won't cycle on and off... without touching the thermostat setting...

once the freezer section is frozen.. the fluid then absorbs no more heat... and stays about -5 or so... the fluid then moves down into the refrig section by gravity... and starts absorbing the heat their... once it gets to the 38 deg (about setting 3-4 on the thermostat) it will shut down the refrig.

You dont want to pre cool the refrig... section first... as the refrig doesn't work that way... if your going to get the max cooling effect and effecency..

so instead of just cooling the interior of the ref section.. and having it cycle down... you add a gallon water container... (drinkable when it cools down) and use it to keep the cycle going until the heat in the water is all absorbed...

if you put a frozen item... in the refrig... then the thermostat could shut down... and could leave the freezer section warmer.... because it thinks the freezer is as cold as its going to get and now the refrig section is cool enough...

So by using the water jug.... then it will stay on until the whole refrig now gets to the thermostat setting... with the freezer section as cold as its going to get...

So nope you want to put a jug of water in.. and allow it to keep the refrig from cycling while it cools down...

[OTRA15]

IMO you are way overthinking this. Please consider . . .

Forget about my suggestion to pre-chill things. Get the system up to speed using your approach.

Then fast forward to a time when the freezer and fridge are both at the correct operating temperatures . . . perhaps a day or two later, after things have stabilized.

Each space is exactly the right temp, and all the food is safe.

OK?

Now turn the unit off, wait one hour, and turn it on again.

Isn't this the same as the suggestion to fill the freezer and fridge with frozen items until both spaces reach the correct temps?

The unit does not know the difference between your frozen water, or the blue ice I want to add at the very beginning, does it? The forums are full of posts in which many experienced AS users pre-chill the fridge/freezer with great results!

Simpler, more energy-efficient, and much faster IMO, although each step may not fit precisely into little pre-conceived conceptual boxes . . .



Over and out -- good luck!

[OTRA15]

PS -- Protagonist nailed it earlier in this thread. Well said, sir!

Originally Posted by Protagonist

As long as the fridge and freezer get cold, the source of the cooling makes no difference. Blue ice, real ice, cold food, beer, or the fridge's cycles. Cold is cold is cold.

The only "fooling" that is taking place is that cold contents may already be colder than the thermostat setting, so that the fridge can't keep the food as cold as it was when the food was first put in. But a bit of experimentation and experience should show you the thermostat setting you need in order to keep the food as cold as it was when you first put it in the fridge.
. . .

[Mollysdad]

Then there's this option. I used this because I'd be exhausted packing the car, driving to the storage lot, and transferring everything to the RV. By the time I could drive away, I didn't feel like it.
So, I'd drive to a campground locally. Park, get everything going, wash the RV (Phew!), and make sure all systems were "go". Then I'd jump in the pool, cool off and relax until the next morning when I was fresh to drive and had a clean RV with a cold fridge.