Fridge Running, Burning Gas, 24/7

Discussion in 'Motorhome Chat' started by callumwa, Aug 14, 2012.

  1. callumwa

    callumwa Read Only Funster

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    Whilst at the Saltfleet Gala meet this weekend. I noticed the fridge (Dometic RML 8555) was running (burning gas) continuously. I could hear and see the burner running and feel the heat venting from the upper exhaust vent. It just never stopped.

    The fridge was cooling ok, food in the freezer compartment stayed frozen, beer was cold.
    If I adjusted the temperature setting the fridge got colder as I increased the setting (checked with a thermometer inside down to 2 deg C).

    I disconnected the thermostat from the cooling fins, gave it a clean and put it back with no difference. The fins were not iced up, and water was collecting and draining on the water trap under the fins.

    I don't remember it running, (burning gas), continuously 24/7 previously...
    There are no error warnings showing on the LCD control panel.


    Any suggestions, ideas etc welcomed.......
     
  2. JJ

    JJ Funster

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    Completely ignorant about modern fridges with their automatic power selection stuff but all my fridges, when on gas, have a flame alight all the time.

    Do the modern ones switch the gas off and then relight as it warms up a little?

    JJ
     
  3. callumwa

    callumwa Read Only Funster

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    Hi JJ, it switches over to gas as soon as the engine stops, when you pull up.

    I can see it's burning strongly through the little aperture when I remove the vent covers. I can actually hear the gas burning from inside the van and outside. But I thought that when the fridge got down to temperature, the gas burner would be regulated by the thermostat so it would be going on and off intermittently, maintaining temperature as required

    It's just that I noticed this weekend it was "burning" constantly without ever cutting off.

    Is this normal is what I'm wondering as I never noticed it before?:Eeek:
     
  4. Diabalo

    Diabalo Funster

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    I think you will find it's supposed to, mines the same.
     
  5. TheBig1

    TheBig1 Funster Life Member

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    when set to gas or if no EHU is detected, the fridge will light the flame 15minutes after the engine stops in case your at a petrol pump. the flame then stays lit all the time gas is supplied and the settings remain the same. the thermostat will control the size of the flame but will remain lit as a pilot light. you should never run a fridge on gas with winter vent covers on due to carbon monoxide entering the van
     
  6. callumwa

    callumwa Read Only Funster

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    Thanks .... I've just never noticed it before. It's was only this weekend I could hear it all the time. Maybe it's just got noisier and needs a service / cleaning.
     
  7. Terry

    Terry Funster

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    Hi,it will always be lit on gas :BigGrin:
    terry
     
  8. Terry

    Terry Funster

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    Hi big 1 you can run the fridge on gas with covers on :Smile:the right hand side has it's own vent that is always open :thumb: This is where you feel the heat :Wink: it is designed to both breath and vent through that bit :thumb: Your fridge should also be sealed off to the inside so no fumes can /should enter the living accommodation :Smile:
    terry
     
  9. callumwa

    callumwa Read Only Funster

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    That's what I thought that the flame should go up and down depending on demand and the pilot will remain light at all times. Ours is running and burning high all the time 24/7...:Eeek:
     
  10. TheBig1

    TheBig1 Funster Life Member

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    in a perfect world where the fridge is fitted to prevent leaks of air or gasses, like building the cabinet yourself, then no flue gasses vent inside the van. In reality, the fridge will work ok, but even if you get the slightest draught around the fridge, that will blow hydrocabons and carbon monoxide into the van. therefore its "best practice" and safer to always remove at least one vent cover when operating on gas and both if you can. helps the fridge work better too

    if you need to use your fridge on gas in sub zero temperatures you really need to ensure the fridge ie hermetically sealed from the burner area and that if the fridge needs to be removed and refitted, then it gets resealed. It doesnt have to be rocket science to seal it, but every euro van I have seen tends to have problems. one in particular I remember seeing there was soot staining on the wall above the fridge worktop. the family that owned the van had no idea what was causing it or why they always had "a hangover type headache" most mornings after a night in the van.
     
  11. TheBig1

    TheBig1 Funster Life Member

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    if the fridge is responding to adjusting the thermostat, it must be adjusting the flame, you maybe cant see the difference. if you can hear a light roaring noise coming from the burner, this often indicates a problem with the jet. it should be virtually inaudible in operation. it could be a build up of oily deposits in the jet or even a tiny bit of rust dropped in there
     
  12. Barclaybasher

    Barclaybasher Funster

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    Are you running the fridge too cold ?
     
  13. callumwa

    callumwa Read Only Funster

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    When on gas I normally run the fridge on 2..... (1 = minimum cooling, 5 = coldest setting).

    Over the course of the weekend I ran the fridge on various settings from 1 to 4 and back to 1.

    On all settings it just kept "burning" strongly, strong enough that I could hear the burner from the overcab bunk... Sounds a bit like a mini hot air balloon burner......:Eek!:
     
  14. andyman

    andyman Read Only Funster

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    We have a Dometic fridge freezer, if it is very quite you can here the igniter spark. So clearly on my unit there is only on when required.
     
  15. scotjimland

    scotjimland Funster Life Member

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    This is the same method as employed by the Dometic / Norcold fridge/freezers fitted to USRVs ..

    the temperature is controlled by switching the gas off/on as required, rather than by adjusting the flame size ..
     
  16. keith

    keith Funster

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    If it's that noisy I would suggest you get it checked, maybe the burner is not burning correctly.

    We don't get ANY noise when ours is on, other than the click click when it starts, as Jim said.
     
  17. callumwa

    callumwa Read Only Funster

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    That's what I had been thinking, as I don't remember hearing it running like this any time before, only the occasional "click click click" of the piezo ignition from time to time.

    I will get it checked / serviced.

    Thanks all......:thumb:
     
  18. scotjimland

    scotjimland Funster Life Member

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    To expand on what I said earlier, and to perhaps shed some light on the problem, there are two types of temperature control systems ..

    Type 'b' will be found on larger fridges and those with a separate freezer box..

    Type (a) The gas is always on, it is lit by a piezo igniter, the flame is varied by a gas valve which is adjusted manually by setting the knob on the fridge panel , usually marked 1 -5 , this is a manual system and has no thermostat in the fridge cabinet.

    Type (b) Electronic system .
    The gas is switched on and off electronically and the temperature is maintained by a thermostat.. the heart of this system is an electronic board, usually referred to as the 'igniter' board , it has four functions

    1. Ignite the gas, (it has an HT coil and lead which creates a spark in the burner).
    2. Open and close a gas solenoid valve to maintain the pre set temperature.
    3. Monitor the flame using thermocouple (flame failure will shut off the gas)
    4. Monitor the fridge cabinet temperature using a thermostat.



    If yours is 'on' all the time and you recall hearing the igniter sparking periodically, it sounds like you have type 'b'

    so, either

    a) the gas solenoid valve is stuck open
    b) the igniter board is faulty
    c) thermostat faulty

    I would check the solenoid valve first, it may well be dirty and stuck open... but if unsure about how to proceed, as you have said, a visit to the dealer is advised..
     
    Last edited: Aug 16, 2012
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  19. callumwa

    callumwa Read Only Funster

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    Hi Jim,

    Thanks for that.. we do indeed have the second type, (b).

    Yesterday I checked the burner was clean, no rust, nothing clogging it, etc.
    I also checked the thermostat (thermocouple) with a meter and it is functioning ok.

    So I guess I need to take a look at the solenoid valve next. otherwise it is off to a dealer.

    We are off up to Scotland today with the boys, so we will be mostly on hook up where it is working without problem. When on gas it is still functioning, just burning gas all the time. We will have some ice packs in the freezer, which I can put in the fridge to help keep the fridge cool so I can turn the gas off for a few hours at a time overnight when we are not hooked up..

    Thanks again Jim.....:thumb:
     
  20. Heyupluv

    Heyupluv Read Only Funster

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    I agree with you callumwa.....yes the pilot will be lit all the time while the engine is not running or when you are not on EHU.....pilot flame is small flame like on a cigarette lighter and should not be noisy or give off any real heat ..or unless it is lit a piezo-electric ignition without a pilot light!! ...it is only when the fridge/freezer drop's below the temperature set you will get a BUFF sound as the burners re-light....it should NOT be on 24/7 unless you in climate of a very high Temperature....and then it will be on and off most of the time..:Doh:
    But I could be wrong BUT that is how ours seems to be working...on and off keeping the fridge cold
     
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