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Get the most from your RV refrigerator

March 26, 2008 by Mark Polk · 26 Comments  
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RV refrigerators, for the most part, are efficient. In many cases it is something the owner does that makes the refrigerator less efficient. For starters keep in mind that your RV refrigerator is different from the one in your house. Your RV refrigerator doesn’t use a compressor or any moving parts for that matter. It works off of the principle of absorption. Instead of applying cold directly the heat is drawn out, or absorbed. The theory is, when there is an absence of heat there is cold. Basically your RV refrigerator uses heat, either from an electric heating element or LP gas flame. The heat starts a chemical reaction and then through evaporation and condensation causes it to cool.

There are several things we can do to help the refrigerator do its job more efficiently. First and foremost the RV must be fairly level for the refrigerator to operate properly. Older RV refrigerators required more precise leveling, but even the newer models need to be close to level for optimum performance. Over time a cooling unit operated out of level will be permanently damaged. As far as the operation of the refrigerator goes, traveling with the refrigerator on will not cause problems because the liquids and gases in the cooling unit are constantly moving around. They don’t collect and stay in areas of the cooling unit like they can in a stationary, out of level refrigerator.

The initial cool down process can take four to six hours. You should turn the refrigerator on the day before you plan to leave, and before you put any food in it. When you do load the refrigerator the food you put in should already be cold, and the food put in the freezer should already be frozen. Putting cold food in the refrigerator, rather than adding warm food, lets the refrigerator work less to cool down. One common mistake made is to over pack the refrigerator. There has to be space between the foods to allow for air to circulate throughout the compartment. In most situations you will have access to a store where you can buy food. A two to three day supply should be enough.

To assist with air circulation you can purchase an inexpensive, battery operated refrigerator fan. Put the batteries in and place the fan in the front of the refrigerator compartment blowing up. The fan will improve the efficiency by circulating the air and it will reduce the initial cool down time by 50%.

The heat created by the cooling process is vented behind the refrigerator. Air enters through the outside lower refrigerator vent and helps to draft the hot air out through the roof vent. Periodically inspect the back of the refrigerator and the roof vent for any obstructions like bird nests, leaves or other debris that might prevent the heat from escaping.

Another good idea is to install a 12 volt, thermostatically controlled refrigerator vent fan at the back of the refrigerator, or at the top of the roof vent, to assist with drafting the hot air away from the refrigerator. If you are mechanically inclined these fans are fairly easy to install, or you can have your RV dealer install one for you. Either way it’s worth it. The fan removes the heat built up behind the refrigerator improving the refrigerators performance by up to 40%.

The outside temperature also affects the operation and efficiency of your RV refrigerator. When it’s cold out you can lower the temperature setting and when it’s hot out you can raise the setting. Some refrigerators are preset by the manufacturer. Extremely hot weather will directly affect the refrigerators efficiency. When it’s really hot outside try parking your RV with the side the refrigerator is on in the shade. Periodically inspect and clean the refrigerator door gaskets. Check them for a good seal. Place a dollar bill behind the seal and close the door. It should stay there and not drop. When you try to pull it out there should be some resistance felt. Do this in several different places and have any damaged seals replaced.

Try to limit the amount of times you open the refrigerator or freezer doors and the length of time you leave the doors open. Last but not least you should always have a small thermometer in the food compartment. Food can begin to spoil at temperatures above 40 degrees.

 RV absorption refrigerators do a great job for RVers. They will do an even better job, and last longer, if we apply these simple tips to make their job easier and less demanding.

Happy Camping,

Mark Polk

RV Education 101

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Comments

26 Responses to “Get the most from your RV refrigerator”

  1. Gerry Schutz on March 26th, 2008 1:03 pm

    Thank you for your helpful info. I do have a question, tho. Many of the RV Parks nowadays are charging extra for electricity. I have a 2003 four door Norcold unit in my coach. Which is more economical to operate it on – LP gas or electric? Both fuels are quite expensive when you’re full timing it.

  2. Gregg on March 26th, 2008 8:42 pm

    12 volt, thermostatically controlled refrigerator vent fan . Where do I get one of these and at what temp. do you set the therm. on ?

  3. Mark Polk on March 27th, 2008 7:40 am

    It’s probably a push either way. The refrigerator is pretty efficient in both modes. Don’t hold me to this, but it is probably in the range of 600 to 1,000 Watts (5 to 8 Amps) in the electric mode and it uses less LP gas than any of the other gas appliances in the RV.

  4. Mark Polk on March 27th, 2008 7:53 am

    The fan I used is a universal mount fridge vent fan by Valterra Products. It’s fully automatic and pre-set to come on at 110 degrees and shut off when the temperature drops to 90 degrees. Here is one link where I found it was available.

    http://www.rvshop.com/catalog/index.php/cPath/23_68

  5. Robyn Hawk on March 28th, 2008 8:34 pm

    We have an older RV and recently our fridge started building up a strong ammonia smell – aside from closing the door and getting out of the RV until we could breathe again what happened and what should we do?

    Fridge is a Dometic RM 2803 Gas/Electric

    Robyn

  6. Mark Polk on March 29th, 2008 7:16 am

    The refrigerator is an ammonia absorption refrigerator. Unfortunately when you smell ammonia it means the cooling unit (or coils) have a leak. The only way to fix it is to have the cooling unit replaced or to purchase a new refrigerator.

  7. Will Grenz on March 29th, 2008 11:34 am

    I am firmly convinced that the RV industry needs to emphasize more the importance of keeping the refrigirator level or near level when it is turned on. I have run into many folks that failed to turn off their frig when their rig was parked in a non level position, myself included. As a consequence the expenditures for prematurely new coils and/or new refrigirators on a nation wide basis are not trivial. A clearly visible warning label on the refrigirator or inside would be very helpful.

  8. Robyn Hawk on March 29th, 2008 9:31 pm

    So – how do you go about changing out a refrigerator? It doesn’t seem like there is room to pull it out? I assume it is pulled out from the inside – right?

    We have installed dishwashers and other built-ins during a kitchen rennovation years ago – do you think it is do-able?

    Robyn Hawk

  9. Mark Polk on March 30th, 2008 7:20 am

    Yes you remove it from inside, but it seems like not all RV manufacturers consider you might need to remove and replace the refrigerator one day. Sometimes you can pull it out and remove it without any problems, but I have also seen where the refrigerator wouldn’t fit through the entry door and a large window needed to be removed to get the refrigerator out of the RV. You might have to partially disassemble it to get it out.

  10. Robyn Hawk on April 1st, 2008 2:40 pm

    Thanks for the info Mark – I really appreciate the assist! Now to find the time!!! LOL!

    Robyn

  11. Maintenance- Cleaning a Norcold Burner on April 2nd, 2008 2:49 pm

    [...] for visiting and enjoy all the information! RV.Net Blog AdminAfter Mark Polk’s great post on getting the most from your RV refrigerator, I though I would get my hands dirty a bit, and give some fairly simple hands on instructions on [...]

  12. Ron on April 5th, 2008 7:40 pm

    Nice article. If folks want to understand better how absorption cooling works here is a good site: http://www.nh3tech.org/abs.html

    BTW, all refrigeration system work by extracting heat. You cannot “inject cold” since “cold” is merely a relative term describing a temperature lower than “hot”. The absence of heat is technically called ” Absolutely Zero” which is the point when atoms are so cold they actualy stop moving. It’s also so cold it has never been fully attained. Therefore all things have some heat heat. It’s just that some things have less heat than others and are therefore “colder”.

    the bottom line is to make your refrigerator cold you must extract heat – regardless of the mechanics used – and that heat most go somewhere else which is why it’s vented to the outside. Air conditioners work the same way. So does a “heat pump”. It’s just an air conditioner working backwards i.e. extracting heat from outside the motorhome and dissipating it inside. That’s why the heat pumps in our motorhomes down’t work too well below 40 degrees F – there is a lot less heat in the air to extract.

    Sorry if this sounds like mumbo jumbo but I thought I’d expand on the concept. Thanks for the useful article!

  13. John on April 6th, 2008 1:58 pm

    Something I did a while ago re. “venting heat from around the fridge” was to install a simple (also cheap) computer cooling fan.

    This is placed so it blows out through the fridge vents and since it’s a 12V device it was no problem tapping into the existing wiring.

    You can definitely feel the heat removed from the area on a warmer day and the fan draws zip in the way of energy.

  14. Ed Weigman on April 7th, 2008 11:44 am

    Mark I have a dometic RM2652 refrig.I have 2 red wires going to the chimney,just like in your pic.is that a fan?I also have a blue wire that isn’t connected to anything.It’s just laying there not connected to anything.It’s not even on the wiring diagram.
    Thanks
    Ed

  15. Mark Polk on April 8th, 2008 8:02 am

    Ed,

    No the red wires going to the flue are not for the fan. The pictures in this post are of a Norcold 1200 model refrigerator. If there is already an existing fan it will be wired to the 12VDC terminal block. You should be able to look in the refrigerator owners manual that came with the RV to identify the wiring for your particular refrigerator.

    The Blue wire (not connected) is more than likely a test lead.

  16. RL Anderson on April 8th, 2008 11:18 am

    We had an opposite problem with our fridge … one that most folks don’t experience … as a matter of fact , over 100 of us had the same problem in our court and the surrounding courts …
    Talking to a fella at work , as we work construction and most of us live in RVs , he told me what he did to cure the problem …
    We tend to work in areas that hit 10 below to 50 below zero in the wintertime … and the liquid in the fridge can freeze in the tubes , before the burner … that said , it will create a bubble after the burner … much like when your fridge is not level .. and it will not cool …
    This particular winter , most of us didn’t have a fridge for over a month due to this … some bought new units …
    Sonny , said that for years he has put a heating pad over that area , not the burner , but the tank to the left … also , not the coils on top and never block the vent …
    we have been doing this for years and many we of us now do this … when the temps climb to zero and above , we remove this … our areas we work in never get too hot where we need a fan , so that is not a problem … ours is freezing …
    One guy claimed he bought a fridge with a built in heater that was computer controled that eliminated the freezing probem … don’t know how that worked …
    Oh , if the fridge ever does freeze up before the burner , of course the fridge quits working … and to remove the air bubble after you get it thawed out , well , you can either drive down a road sloshing the fluids . or remove the fridge and lay it down sideways or upside down … and it will gurgle … then reinstall it …
    After ours froze initially , and quit , we have run a heater on it for several years and never lost refridgeration since …
    OH , and by the way … one of the guys talked to an RV dealer and he said that the fridge couldn’t freeze up … dunno , it happened to an awful lot of us , and every winter , a lot of my neighbors freeze up … and we get a lot of them thawed out …
    did I mention that we RV full time ???
    RL Anderson
    no7j@yahoo.com

  17. Pat on May 4th, 2008 9:58 pm

    I was wondering if it is normal for the freezer to stay cool long after it has been shut off? The bottom of our freezer compartment was still freezing cold weeks after the fridge was shut down.

  18. Bill Lawson on May 8th, 2008 4:10 pm

    i was wondering if my fridge coil is getting hot but my fridge does not cool down do i need to buy a new one or do you think something else is wrong

  19. Elise on May 29th, 2008 7:38 pm

    Now, Mark, what can you tell me about washer/dryer combo units? Best brand? Good place to look for a deal? Things I should watch out for if I’m buying a used one? How to install?

  20. April Richardson on August 5th, 2008 6:54 am

    I followed your instructions for cleaning a norcold burner. It definitely made a difference but the fridge is still not cooling as good as it should on propane. Works great on AC when generator is running. Any suggestions?

  21. Rhena Morris on August 5th, 2008 10:30 am

    What kind of heating pad did you use and where exacting did you place it in the back of the fridge? I had purchased a battery heater pad but it was too large to place in the back of the fridge therefore I used a trouble lamp instead and also placed insulation in the outside vent area. This worked great until it got to -45 for 2 weeks. The fridge froze up but when it got warmer came back to life. I found it also helps to park your RV so that the fridge is on the east side and then the sun helps keep it warm durning the day. We are also full timers and pipeline workers.

  22. Pat on January 7th, 2010 2:07 pm

    So where do you level from for the refrigerator? The trailer Frame? The floor? The floor of the frig?

  23. Brian on October 12th, 2010 10:15 am

    I saw some posts about getting your gas absorption RV refrigerator to work well in sub zero temperatures and thought I’d pass on some advice. The problem is not that the Ammonia solution freezes and thickens at all. The only problem is that your flu tube is getting too cold and causing the ammonia solution to condensate in the wrong spot. When the flu gets too cold (ambient temperature below 20 degrees F) the ammonia solution will condensate right in the flu and then simply fall right back down and repeat the process. Some people have solved the problem by hanging lightbulbs and heat lamps in the rear of the refrigerator but that is clearly a fire hazard. My recommendation, and something that I’ve been doing for years and years with NO problems at all, is simply block the upper vent. You need to MAKE SURE that when it warms up above freezing, you unblock that vent or else you have another fire hazard but so long as you remember that it is blocked off this will help keep your flu tube warm enough to allow the condensation to start at the condenser fins at the top (where it should be) and start the flow of ammonia through the cooling unit like it was designed. If you have any questions feel free to give me a call. I am a Technician at RV Vacation Nation (www.RVVacationNation.com) and would be happy to assist you in any way that I can.

    ~Brian

  24. Glenn on November 20th, 2011 2:27 pm

    Thanks to Brian from RV Vacation Nation. We’re building a house in Alaska right now and its been subzero temps for the last couple of days, and of course our RV’s fridge stopped working efficiently. Being new RVers, I assumed that Dometic would have something in their manual, website, etc. as to what ambient temperature range their units work in. Bad assumption.

    Simple solution; going to do it today. Once again, Thanks Brian.

  25. Glenn on November 20th, 2011 2:56 pm

    Hopefully Brian with RV Vacation Nation still looks at this blog. My question to him, or anyone else, is that if I completely block off the upper vent aren’t there going to be issues with the exhaust gas backing up when the refrigerator is operating in the LG mode?

  26. solar tracker on June 22nd, 2012 12:12 am

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