Leveling & Refrigerators
- Thread starter Rodbuster
- Start date
JJOren
Well-known member
Ammonia based refrigerators don't have to be absolutely level, but they do have to be close to cool properly. Get them off level far enough and you will burn out the refrigerator all together. The difference between shore power and propane is that shore power uses a heating coil instead of a flame to provide the power for cooling.
danemayer
Well-known member
Dick,
The refrigerant is heated and rises to the top of the cooling unit and then falls through a zig zag tubing arrangement. Gravity draws the refrigerant down through the tubing. If you're not level, especially front-to-rear, the angle of the zigs and zags changes and the refrigerant doesn't fall at the correct rate, or in a severe enough situation, doesn't fall at all. If it falls at the wrong rate, cooling is compromised. If it doesn't fall at all, it pools and can gel in the tube, creating a blockage that ruins the cooling unit. You can see in this picture that the tubing is not at a very steep angle, so it wouldn't take much to screw up the rate of refrigerant descent, and resultant cooling.
The refrigerant is heated and rises to the top of the cooling unit and then falls through a zig zag tubing arrangement. Gravity draws the refrigerant down through the tubing. If you're not level, especially front-to-rear, the angle of the zigs and zags changes and the refrigerant doesn't fall at the correct rate, or in a severe enough situation, doesn't fall at all. If it falls at the wrong rate, cooling is compromised. If it doesn't fall at all, it pools and can gel in the tube, creating a blockage that ruins the cooling unit. You can see in this picture that the tubing is not at a very steep angle, so it wouldn't take much to screw up the rate of refrigerant descent, and resultant cooling.
boatto5er
Founding VA Chap Ldr (Ret)
Dick, you probably just have the same problems I do. The 1350 model just doesn't work well. I changed the angle of the baffle at top of mine and I've got two old PC cooling fans I'm going to install to get more air circulation in the back.
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sundancer87
Member
The cooling fans are a mystery to me. The perc tube utilizes either gas or electricity to heat the solution to a boil. Once boiling it perculates up through the coils and condenses and brings the heat from the inside with it to be boiled and perked all over again.
Where does a cooling fan enter into this process? Why cool something that needs to be boiled to work? Why cool the solution at all? The idea is for it to absorb the heat is it not?
The best way is to keep the ambient temperature below 80 degrees, then the thing will work like it has good sense. Muffin fans haven't proven to be beneficial for my application.
I know they work better in cooler temperatures and I have tried all kinds of things to make mine work better above 80 degrees and it just doesn't happen. The only fan solution is one inside the box to move air around but I think those are a waste of money too.
Where does a cooling fan enter into this process? Why cool something that needs to be boiled to work? Why cool the solution at all? The idea is for it to absorb the heat is it not?
The best way is to keep the ambient temperature below 80 degrees, then the thing will work like it has good sense. Muffin fans haven't proven to be beneficial for my application.
I know they work better in cooler temperatures and I have tried all kinds of things to make mine work better above 80 degrees and it just doesn't happen. The only fan solution is one inside the box to move air around but I think those are a waste of money too.
danemayer
Well-known member
The liquid is heated to cause it to rise from bottom of the frig to top. That's when the real work starts.
At the top, the ammonia is condensed and then goes through an expansion process that causes a rapid and dramatic reduction in temperature. That makes it cold so it can absorb heat from the refrigerator.
The heat lost during the expansion process and the heat absorbed from the refrigerator has to be removed from the back of the unit. The fans on the back increase airflow across the fins to remove that heat.
If you don't get rid of the heat from this process, the refrigerator's efficiency will be reduced and it will not get to the desired temp. When refrigerators are mounted in slideouts, the hot air cannot vent straight up, so after passing over the fins, it has to take a turn to vent. Baffles help direct the air through that turn.
If you let warm air into the refrigerator by way of keeping the doors open, having air leaks, or by high temps inside the coach, it won't matter how many fans you have or how well your baffle works.
sundancer87
Member
How is the heat and exhaust removed from a slideout? Having lived with a gas refrigerator for 20 years and having tried all the tricks and having actually replaced the perc tube on a few of them all I can say about the fans is this, in a slide out they may be effective if their job is to remove the excess heat and exhaust that is trapped in the slide out.If the refrigerator is out in the open then they won't be helpful unless they can drop the ambient temperature to a level that is more beneficial to the absorption process.
danemayer
Well-known member
How is the heat removed when the refrigerator is in a slideout? There's a lower vent and an upper vent. Air comes in the lower vent, blows across the fins, and exits out the upper vent.
How does this work if the refrigerator is 'out in the open'? I assume you mean it's against a wall that is not part of a slideout. In that case, the heat is vented straight up and out through the roof. I would expect there's still a lower vent on the outside for incoming air.
If you want to know more about how RV refrigerators work, you can always do a Google search on RV Refrigerator Theory. Here's the first link that comes up.
I'm a little confused by your posts. On the one hand, you've said you've got 20 years experience and have tried all the tricks. On the other hand, you've said much of it is a mystery. Are you actually looking for information, or are you trying to say that RV Refrigerators don't meet your expectations? Maybe something else?
How does this work if the refrigerator is 'out in the open'? I assume you mean it's against a wall that is not part of a slideout. In that case, the heat is vented straight up and out through the roof. I would expect there's still a lower vent on the outside for incoming air.
If you want to know more about how RV refrigerators work, you can always do a Google search on RV Refrigerator Theory. Here's the first link that comes up.
I'm a little confused by your posts. On the one hand, you've said you've got 20 years experience and have tried all the tricks. On the other hand, you've said much of it is a mystery. Are you actually looking for information, or are you trying to say that RV Refrigerators don't meet your expectations? Maybe something else?
sundancer87
Member
What I'm saying is that I live in a house, not a mobile unit of any kind, that has utilized an LPG regrigerator for 20 years. I did have a small TT with a 1303 in it and I became very familiar with the exterior vent door to the burner unit and the roof vent. I installed them myself.
My questions are regarding today's mobile units with LPG refrigerators in slide out, something new for me but might be something I'll have to deal with in the next few months.
The next question, do some people with refrigerators in slide outs have them operating on gas as they travel.
I'm not sharp shooting anyone here, just trying to get a handle on what is happening in the industry since the 20 years ago that I moved out of my modified TT. It is a little different living with a gas refrigerator full time as opposed to firing one up for a long weekend or a little trip.
I have a 16 cu.ft. gas refrigerator in the house now. I've replace the unit twice so far and I am very familiar with how it operates. If my questions bother you or confuse you mr. moderator I can take my questions elsewhere if you so desire.
My questions are regarding today's mobile units with LPG refrigerators in slide out, something new for me but might be something I'll have to deal with in the next few months.
The next question, do some people with refrigerators in slide outs have them operating on gas as they travel.
I'm not sharp shooting anyone here, just trying to get a handle on what is happening in the industry since the 20 years ago that I moved out of my modified TT. It is a little different living with a gas refrigerator full time as opposed to firing one up for a long weekend or a little trip.
I have a 16 cu.ft. gas refrigerator in the house now. I've replace the unit twice so far and I am very familiar with how it operates. If my questions bother you or confuse you mr. moderator I can take my questions elsewhere if you so desire.
danemayer
Well-known member
Thanks for explaining. It's not uncommon for people to jump into the middle of a thread and take it to a new discussion, but it can be confusing if the new questions are in a different context.
In answer to your question, yes many people run on LP while towing. Others do not. I think the ones who do not are mostly concerned about having LP tanks open in the event of a collision. Some safety experts say that's dangerous. In addition, the manufacturers warn in particular against having the refrigerator running on LP while refueling, because of the danger of having an open flame near fuel vapor.
In answer to your question, yes many people run on LP while towing. Others do not. I think the ones who do not are mostly concerned about having LP tanks open in the event of a collision. Some safety experts say that's dangerous. In addition, the manufacturers warn in particular against having the refrigerator running on LP while refueling, because of the danger of having an open flame near fuel vapor.
Dan
I too have a 2012 rushmore and having cooling problems with refer, dometic told me to carry it to camping world for repair under warrenty. the freezer works just fine bottom want get below 43.I have checked the seals and center door piece and did not find any leakage. what can I expect from camping world on repair? refer is 1350 w/ice maker. bought new oct 2011.
hot summer in arkansas
Wife not happy
I too have a 2012 rushmore and having cooling problems with refer, dometic told me to carry it to camping world for repair under warrenty. the freezer works just fine bottom want get below 43.I have checked the seals and center door piece and did not find any leakage. what can I expect from camping world on repair? refer is 1350 w/ice maker. bought new oct 2011.
hot summer in arkansas
Wife not happy
danemayer
Well-known member
I think there's a lot of variability in how well the service techs deal with 1350 issues. If they call Dometic for guidance, they'll probably be directed to test the cooling unit by running in bypass mode for 24 hours with a thermometer in a gallon of water to see if it reaches a target temperature of 43 or less. They may also test for proper resistance of the thermistor by placing it in cold water.
If you can check your freezer and refrigerator actual temps with a thermometer, that may be of help to direct the diagnosis a bit. If the freezer is working well, there's a lot of stuff that is working correctly, so knowing that, you should ask them to check for air infiltration into the cabinet space. The drain tube also needs to be checked for loss of the end cap or other air leaks. (Before taking it in, you can check the drain hose at the lower vent on the outside.) They should be checking these things anyway, but if you discuss it with the service tech, he might look a bit harder.
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