Forum Discussion

NKnowland's avatar
NKnowland
Explorer
May 09, 2021

Dometic fridge not cooling on LP. Just LP.

The fridge/freezer works great on AC and DC.
The freezer works great on LP.
The fridge sucks on LP..

So this is only an issue on the LP side that just impacts the fridge.

The burner unit was cleaned/inspected professionally. Good flame. Manometer 11.1. New baffle. Air blow to clean flue.

What else is there to try???
  • NKnowland's avatar
    NKnowland
    Explorer
    May 19, 2021
    Thank you ALL. It was the burner. One good cleaning and we are back in business. Esp thanks to the person who suggested taking a second look at the burner, which we hadn’t done since we had recently had it cleaned &inspected. Another case for doing your own work.
  • dougrainer's avatar
    dougrainer
    Nomad
    May 17, 2021
    NKnowland wrote:
    Yes! Obstructed burner was the culprit. Thanks so much.


    You stated it was professionally cleaned. ????????????????? So, Burner obstructed or the Orifice? Either way, you did not get a professional cleaning done as these items are done for a LP operational complaint. Doug
  • NKnowland's avatar
    NKnowland
    Explorer
    May 17, 2021
    NKnowland wrote:
    NRALIFR wrote:
    I’d get a second opinion on that burner, or buy a manometer and check the LP pressure myself. It should be at least 11” wc WITH the LP system loaded about 50%, which means you ought to be running the furnace and water heater while checking the pressure.

    I just noticed you said new baffle, so I removed that suggestion.

    Seriously, check the LP pressure again. The flame can LOOK good, but still be too low btu-wise.

    :):)


    We’ve got a manometer and it reads 11.2 under load,
  • NKnowland's avatar
    NKnowland
    Explorer
    May 17, 2021
    Old-Biscuit wrote:
    Freezer/Food compartment get cold on AC element and stays cold on DC element
    But freezer only gets cold (not the food compartment) when using GAS

    That means GAS is NOT generating ENOUGH hot ammonia vapor.....
    Low LP System Pressure causes cool gas flame cause insufficient boiling of ammonia into hot vapor
    *freezer is first in coolant flow......freezer gets cold cause there is enough absorption but not enough for food compartment

    LP System Pressure OR obstructed burner orifice inhibiting the gas flow to burner

    YES! Cleaned the burner yet again. And that was it. The end of a long, frustrating journey!

    Side note:
    'Fridge'----that is the whole unit Freezer AND food compartment
    'Fridge' is short for Refrigerator
  • dougrainer's avatar
    dougrainer
    Nomad
    May 10, 2021
    The LP pressure should be 11.5 no load and with just the refer running 11.5. LP pressure is CRITICAL for correct Refer LP cooling. It is also BEST to check the LP pressure at the refer tap. Doug

    LOTS OF SUGGESTIONS, BUT WITHOUT YEAR BRAND MODEL OF RV AND MODEL OF REFER AND IF IN A SLIDE OUT OR NOT, NOBODY CAN GIVE BETTER ANSWERS.

    Last, WHY was the baffle replaced????????? How do we know the CORRECT length baffle was installed????? The baffle is CRITICAL for LP cooling
  • NRALIFR's avatar
    NRALIFR
    Explorer
    May 10, 2021
    Dan, the propane regulator I have currently is adjusted by turning the adjuster under the dust cap clockwise to increase the pressure, counterclockwise to decrease. Sometimes it’s marked on the regulator or the adjuster. You shouldn’t have to turn the adjuster very much at all to see a change in pressure. Having to turn the adjuster many turns, or finding that you’ve bottomed the adjuster is a sign that you need to replace the regulator.

    There is a test port on the fridge LP valve just before the orifice where you are supposed to connect your manometer, so you should use that if at all possible. On my fridge, I can’t get that plug out for some reason, so I have to use one on the generator. Using the test port on the fridge would verify that the gas valve is opening like it should, and the LP line doesn’t have a blockage of some kind. Yes, the lines can get blocked with a thick, dark oily goo at times. You might need to check for that.

    When I’ve removed the flue baffle to check or replace it, I’ve always run a 10 gauge shotgun brush up and down the flue to clean it as well. Since your baffle was replaced, can you verify that the correct one was used, and that it’s installed correctly? The baffle has to hang in the right spot inside the flue in order to concentrate the heat in the correct area. So if the new baffle is perhaps for a different model, there’s a chance the wire isn’t the right length for your fridge, or the flat twisted metal part isn’t the right diameter to fit your flue.

    I’ve always just bought my parts from whatever parts dealer I can find on the interweb that can get me the parts quickly. Finding the part number used to be the hardest part, but many of the parts dealers now have very good parts breakdowns on their website. Once you find the part number, then you can even just go to Amazon and find the best deal that way. Seems like when I was looking for the orifice part number for my fridge, I noted that there are different sizes available. There’s the default size that is always on a new fridge, then there’s one or two other sizes for high-elevation use.

    :):)
  • NKnowland's avatar
    NKnowland
    Explorer
    May 10, 2021
    NRALIFR wrote:
    I’d get a second opinion on that burner, or buy a manometer and check the LP pressure myself. It should be at least 11” wc WITH the LP system loaded about 50%, which means you ought to be running the furnace and water heater while checking the pressure.

    I just noticed you said new baffle, so I removed that suggestion.

    Seriously, check the LP pressure again. The flame can LOOK good, but still be too low btu-wise.

    :):)


    We’ve got a manometer and it reads 11.2 under load,
  • NKnowland's avatar
    NKnowland
    Explorer
    May 10, 2021
    John Wayne wrote:
    Make sure the flame is going up the center of the tube.

    Yes, it is.
  • NKnowland's avatar
    NKnowland
    Explorer
    May 10, 2021
    NRALIFR wrote:
    Old-Biscuit wrote:
    ………
    LP System Pressure OR obstructed burner orifice inhibiting the gas flow to burner
    ……….


    That’s a good point, an obstructed orifice could result in the same symptoms as low LP pressure. Soak it in alcohol then blow it out to clean it, or just replace it.

    It’s clearly an issue of not enough heat BTU’s are going into the cooling unit when running on LP, so the cooling unit performance is degraded. On mine, the flame produced with low LP pressure looks virtually the same as the flame produced with correct pressure. The only thing that’s noticeably different to me is the SOUND the flame makes. When the pressure is low, it’s almost silent. When the pressure is correct I can hear the flame without even removing the outside panel. I didn’t even realize that until I bought a manometer and adjusted the LP pressure myself. After adjusting it and hearing the flame, it was an “Oh yeah, I remember that sound now” moment for me.

    And yes, get a wireless fridge thermometer that will let you monitor the fridge and freezer temps without opening the doors. My fridge, which is probably smaller than the average fridge because it’s in a truck camper, will cool down quite rapidly on AC or LP when it’s working right. When something is wrong, I can tell pretty quickly.

    We have a manameter and got a reading of 11.1 under loaf.

    How did you adjust the LP pressure yourself? It doesn’t seem obvious which direction to turn.
    :):)

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,228 PostsLatest Activity: Apr 04, 2025