Extreme cold affecting fridge?

[Chip Arnold]

The Dometic fridge in my '76 Soveriegn stops cooling at times. If I turn the temp setting colder if cools again but then gets too cold after a while. I think I'm seeing a pattern wherin when the outside temp is very low, (nights have been in the teens and low twenties) it stops cooling and when it's warmer outside it works normally. Has anyone had this experience? is the outside temp fooling the fridge thremostat somehow?

[CanoeStream]

Heat pumps lose efficiency and effectiveness when outside temperatures get below 40 or so. There will be some reader who knows more specific details as it relates to fridges. Up north here we hear of issues maintaining cold on freezers kept in cold garages for instance. It's a very local word, but you might see stuff in thar 'unthaw.' No clue here whether raising the trailer interior temperature might help.

Please speak up fulltimers!

[fltlevel510]

Found this small blurb doing a google search. Hope it is helpful. I think most fulltimers are in search of a constant 72 degree locations.

Of Special Note: Your RVs Refrigerator is very vulnerable in cold weather. Your RVs refrigerator has chemicals in the cooling unit that will gel up like diesel fuel if the outside temperature gets down too far. This will stop your refer from working properly. There needs to be a certain amount of heat in the vented compartment behind the refer for it to operate as it should. For that reason, it is important to park your RV so the back of the refrigerator gets as much southern exposure as possible. While this will not guarantee that your refer will continue to work, this will help. If that is impossible to do or if it is extremely cold, you can open the access door on the outside of your RV and add a bat of UNFACED FIBERGLASS INSULATION to cover the vent holes in the lower compartment access, thereby slowing down the circulation of air through the compartment and keeping some of the heat in. A single bat of unfolded and unfaced R11 should be good enough.You are not trying to completely block off the vent... you Just want to slow down the movement of air through the compartment on the backside of your refer. NOTE: Use only UNFACED fiberglass insulation as it is not adversely affected by heat sources or open flame. AS a suggested rule, place the bat in the compartment when the outside temperature gets down to and stays below 15 degrees... just remember to pull the bat out the next spring or the refrigerator will run too hot and will stop working as well. NEVER cover or block the upper vent. In conjunction with the UNFACED fiberglass bat, I've seen the use of a small shielded 60 watt bulb in the bottom of the compartment to help further provide heat to the cooling unit in cold weather as well. Just insure if you use the bulb, place it in a drop light socket with shield and place it away from wires or anything else it may come in contact with. THE MAJOR REFRIGERATOR MANUFACTURERS FROWN ON THIS PRACTICE SO, IF YOUR REFRIGERATOR IS STILL UNDER WARRANTY, YOU MAY WANT TO FIND AN ALTERNATIVE MEANS TO KEEP YOUR FOOD COOL. The major manufacturers provide for no preventive maintenance in this area. It was explained to me that an RV refrigerator goes in an RV... Following that thought, an RV is what it is... a RECREATIONAL VEHICLE, and the use of their product was not intended for extreme cold weather operation. Thus so, the procedure for a frozen cooling unit is to remove it from the RV and let it thaw in a heated garage or room for at least 72 hours or more and then retest it for operation before re-installing it. Why wait for it to freeze in the first place? Preventive maintenance is the key.

As a note, I've also seen owners fill the outside of the refer access panel with the grey or white split styrofoam pipe wrap. They just cut them to length and fill the three vents, so commonly seen on Dometic and Norcold access panels. These syrofoam tubes fit snug and, because they are on ther outside of the access panel, they make more room for a drop light and are seen easily so, come spring... you will remember to remove them.

So ,how do you know when your refrigerator is froze up? It is a pretty good indication that the chemicals have gelled up is when:

The outside temperature has been below 15 Degrees F or less for several days
The refrigerator has stopped cooling on the inside
Touching the Chimney (Commonly a silver vertical tube on the right side of the back of the fridge behind the access panel) is warm while at the same time, the absorber vessel ( a big grey or black horizontal canister sitting the middle of all of the tubes in the back of the fridge, also behind the access panel) is cold. To prevent damage to the cooling unit, immediately TURN OFF YOUR REFRIGERATOR AND CALL A SERVICE TECHNICIAN.
NOTE: AFTER your refrigerator is froze up, the ONLY thing an RV Technician can do is remove the unit and place it in a warm place for 48 to 72 hours to let it thaw out. He must also test it for proper operation before re-installing it in your RV.

[Jammer]

Originally Posted by Chip Arnold

The Dometic fridge in my '76 Soveriegn stops cooling at times. If I turn the temp setting colder if cools again but then gets too cold after a while. I think I'm seeing a pattern wherin when the outside temp is very low, (nights have been in the teens and low twenties) it stops cooling and when it's warmer outside it works normally. Has anyone had this experience? is the outside temp fooling the fridge thremostat somehow?

Sort of. The usual problem is that the freezer warms up while the refrigerator stays cold. The reason is that thermostat for the fridge is in the refrigerator compartment. In cold weather, the refrigerator compartment will rarely if ever warm up enough for the thermostat to turn on, and so the freezer will warm up.

Some newer fridges have a "Low Ambient Control (LAC)" switch which does nothing more than keep the light on when the door is closed. This adds just enough head to the fridge section that the cooling unit will still run and keep the freezer frozen. You could add this to an existing fridge fairly easily if you wanted.

Originally Posted by CanoeStream

Heat pumps lose efficiency and effectiveness when outside temperatures get below 40 or so. There will be some reader who knows more specific details as it relates to fridges.

It's not the outside temperature per se but rather the difference between the hot and cold areas. If the "cold" area (the fridge interior) is warmer than the "hot" area (outside) then efficiency theoretically goes to infinity, because the heat will move by itself.

Up north here we hear of issues maintaining cold on freezers kept in cold garages for instance. It's a very local word, but you might see stuff in thar 'unthaw.'

Household freezers have trouble with really cold temperatures because the compressor oil becomes too thick. It's a problem of materials science, not thermodynamics.

Originally Posted by fltlevel510

Found this small blurb doing a google search. Hope it is helpful. I think most fulltimers are in search of a constant 72 degree locations.

Of Special Note: Your RVs Refrigerator is very vulnerable in cold weather. Your RVs refrigerator has chemicals in the cooling unit that will gel up like diesel fuel

Permit me to be skeptical. The mixture of water, sodium chromate, ammonia, and hydrogen isn't going to gel. If it's cold enough it will freeze. I don't know the exact ratios of water and ammonia that are used in the cooling unit, but typically the freezing point is around -100 F.

[Phoenix]

When its really cold and our propane tank(s) aren't at least half-full, we have trouble with our hot water heater not starting. If we switch to the full tank, the problem goes away. Could it be that the refrigerator isn't running because of low propane pressure, caused by the tank not being full and the cold outside temperatures? Or, does this also occur when the fridge is running on shore power?

[Chip Arnold]

Hmmm, food for thought. This afternoon I put a thin layer of fiberglass insulation over the vent which is behind the fridge in the floor. I don't think it'll be as cold tonight as it was last night but we'll see what happens.
The fridge does stay cold while the freezer warms so I'm thinking there's truth to that idea. How to fix it without putting a bulb in the fridge? The freezer refroze today when the outside temp was up to 30.

[Chip Arnold]

Oh and I'm running the fridge on shoe power. I've never tried using the gas burner.
Thanks everyone for the tips.

[Jammer]

The cooling unit cools the fridge and the freezer at the same time so the only way to get the freezer to freeze without making the fridge freeze too in really cold weather is to put some sort of heat source in the fridge, or propping the door open a little or something.

[Dwight]

Is there a nominal temp range for the frig to operate properly?