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Old 07-11-2013, 02:23 AM   #11
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Originally Posted by herk7769 View Post
This is because the fridge operates by boiling ammonia; not by using a compressor. Propane is more thermally efficient than the electric heater element; it can supply way more heat quickly.

Does your fridge have a thermistor in the cooling compartment or does it have a manually adjustable (but electronic) or automatic control? They all have a means of adjusting the temperature inside (provided it is working properly).
Our fridge has the first type of control panel in your post Herk.
I will see if there is a thermistor or something attached to the fins in the next day or two as we getting ready for a weekend at the beach.
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Old 07-11-2013, 09:45 AM   #12
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I figured it out. The refrig does have a heater cable to prevent icing in humid conditions - which is on automatically whenever the refrig is turned on. When dry camping (12v battery power only) the heater cable still draws about .5 Amp/hr continuously while running on propane.

I followed the wiring diagram posted on the rear of the unit and eventually found that the lamp housing inside the refrig has two 12v wires - one is for the lamp to turn on when the door opens, and the other is the power to the heater cable.

I decided to cut the heater cable wire and splice in a switch next to the lamp. The switch mounted nicely on the bottom of the lamp housing. I can now turn off the 12v heater cable while dry camping, with the refrig on propane, and turn it back on again if I wish to use the climate control feature when on AC power.
Good deal and idea!
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Old 07-19-2013, 08:46 AM   #13
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Just a quick question... we have a Dometic with a CC switch at top of freezer door.. The freezer works very well, but the refrigerator does not get cold. Milk is actually kind of 'warm' . When running on Propane... shld this switch be on or off? shld the slide on the fins be at the top for the coldest or the bottom? We have tried both and doesn't really make a diff where its positioned on fins.. Local Dealer said bottom is coldest?????? Someone help! Not very fond of Dometic.
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Old 07-19-2013, 09:01 AM   #14
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Originally Posted by rocko View Post
Just a quick question... we have a Dometic with a CC switch at top of freezer door.. The freezer works very well, but the refrigerator does not get cold. Milk is actually kind of 'warm' . When running on Propane... shld this switch be on or off? shld the slide on the fins be at the top for the coldest or the bottom? We have tried both and doesn't really make a diff where its positioned on fins.. Local Dealer said bottom is coldest?????? Someone help! Not very fond of Dometic.
Coldest position.
Also make sure probe is at the top of that slider. As sometimes it slides down to bottom.

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Old 07-19-2013, 09:58 AM   #15
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Coldest position.
Also make sure probe is at the top of that slider. As sometimes it slides down to bottom.

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Old 07-19-2013, 01:45 PM   #16
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Originally Posted by rocko
Just a quick question... we have a Dometic with a CC switch at top of freezer door.. The freezer works very well, but the refrigerator does not get cold. Milk is actually kind of 'warm' . When running on Propane... shld this switch be on or off? shld the slide on the fins be at the top for the coldest or the bottom? We have tried both and doesn't really make a diff where its positioned on fins.. Local Dealer said bottom is coldest?????? Someone help! Not very fond of Dometic.
Frame switch should be off unless you have an icing condition around the freezer frame with warm milk the heater is making it worse.
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Old 07-19-2013, 02:44 PM   #17
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Originally Posted by rocko View Post
Just a quick question... we have a Dometic with a CC switch at top of freezer door.. The freezer works very well, but the refrigerator does not get cold. Milk is actually kind of 'warm' . When running on Propane... shld this switch be on or off? shld the slide on the fins be at the top for the coldest or the bottom? We have tried both and doesn't really make a diff where its positioned on fins.. Local Dealer said bottom is coldest?????? Someone help! Not very fond of Dometic.
You (or the dealer) misunderstood the comment.

1) The cold air is denser so it goes to the bottom of the fridge.
2) The Thermistor turns the "cold maker" on when the temperature AT the level of the thermistor gets too warm.
3) The lower the Thermistor is, the less it wants to call for coldness.
4) The higher the Thermistor is, the earlier it gets warm and the sooner it calls for "coldness."

So your dealer is correct, lower in the fridge it is "more cold" than higher (but not the answer you needed); BUT:

if the fridge is not cold enough, the Thermistor needs to be higher so the cold maker comes on sooner.
if the fridge is too cold (eggs freezing), the Thermistor needs to be lower so it does not run so much.

The FREEZER section works separately than the fridge. It gets the coldest gas and chills a large plate attached to the back of the freezer. That plate's coldness is only indirectly controlled by the Thermistor. Since it gets first call on "coldness" and "full cold" is the desired state, there is no "warmer" setting.

The temperature in the freezer depends way more on the efficiency of the system and less on the setting of the Thermistor.

To keep the freezer at its coldest:

1) Never open the freezer unless you know exactly what you are going in there for; get it and close the door.
2) Run the fridge on propane and not electric as the propane is a more efficient boiler of ammonia than the AC heating element.
3) SHADE the fridge vent inlet. Cooler air entering at the bottom will cool the hot ammonia gas quicker and more completely than hotter air.
4) VOLUME - Add fans to the coil vent system to increase the volume of cooling air across the coils.
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Old 07-19-2013, 02:54 PM   #18
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I was having trouble getting the frig cool enough. It was running in the 47/52 range during vacation. I had the trailer a little high in the front to keep the Ac dripping at the rear. When we returned from vacation, we are now full timing it. I suspected the tilt was the problem. Our first setup, which I thought was level, wasn't. I releveled the trailer about a week ago using the living room floor as the level measuring location. Now I've had to slide the thermo-thingy as low as it will go. Temp hovers at 33 degrees now.
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Old 07-19-2013, 02:59 PM   #19
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I was having trouble getting the frig cool enough. It was running in the 47/52 range during vacation. I had the trailer a little high in the front to keep the Ac dripping at the rear. When we returned from vacation, we are now full timing it. I suspected the tilt was the problem. Our first setup, which I thought was level, wasn't. I releveled the trailer about a week ago using the living room floor as the level measuring location. Now I've had to slide the thermo-thingy as low as it will go. Temp hovers at 33 degrees now.
Excellent point! Efficiency is everything. If the fridge is out of level even a little bit in the direction of the coil return, ammonia liquid will slow down in the curves. As the out of levelness increases, that slow down will result in pooling of the liquid in the curves reducing the inside diameter due to the liquid.

That reduction in inside diameter will slowly reduce the return of liquid to the reservoir until you are trying to boil an "empty pot" and at that point the tubing can overheat and crack causing coolant loss and a VERY expensive repair.
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Old 07-22-2013, 10:20 AM   #20
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So... if you have added a small fan inside of the refrig (e.g., small computer twin fan), which circulates the cool air - would likely decrease any temperature gradient inside the refrig, the thermister position would be less significant?
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