Dometic RMD 8505 – help please

Discussion in 'Fridges & Ovens' started by keithchesterfield2, Nov 13, 2018.

  1. keithchesterfield2

    keithchesterfield2 Funster

    Joined:
    Oct 16, 2018
    Messages:
    61
    Location:
    CHESTERFIELD DERBYSHIRE
    Ratings:
    +257
    Sorry if this has been covered before but I can't find a link to this particular problem.

    We have a Dometic RMD 8505 Fridge /Freezer that is around 6 years old

    It worked very well from new on engine, EHU and Gas until last week – we were away in the MH about three weeks earlier and it was okay then.

    Last week it wouldn't get cool on any of the three power sources on the journey to the site (80 miles) or when we were on site parked on level ground.

    The gas pilot light was working but I couldn't hear any clicking when on EHU – I'm not sure if it should click on EHU.

    I tried it a few times the same day and the following day but still it wouldn't cool.

    On the next day I tried again and to my delight it cooled down to its correct temperatures and has worked okay since then.

    The Motorhome hadn't moved since we arrived on the first site but the Dometic continued working when we moved to another site and still seems okay.

    Any ideas of the possible causes - mains voltage unit and cooling unit have been mentioned as possible reasons when talking to local fridge/freezer engineers – but I wondered if anyone else had had the same problem with the Dometic RMD 8505 ?

    Any help appreciated.
     
  2. Robert Clark

    Robert Clark Funster Life Member

    Joined:
    Jul 12, 2014
    Messages:
    9,496
    Location:
    East Sussex
    Ratings:
    +46,157
    We've had a couple of 8505's and would make the following observations;

    There was no pilot light, there was a spark ignition.
    The spark ignition will not work when plugged into EHU, unless you have switched from auto mode to gas mode.
    The fridge takes about 5 hours to get cold, much longer than it takes to drive 80 miles.

    I'm wondering if you've switched from Auto mode to one of the manual modes?
    If you had switched it to 12v mode, this wouldn't work when on EHU as the engine needs to be running for 12V to work.

    I'd suggest checking that the unit is set to Auto mode and see what happens.

    Hope this helps?
     
  3. keithchesterfield2

    keithchesterfield2 Funster

    Joined:
    Oct 16, 2018
    Messages:
    61
    Location:
    CHESTERFIELD DERBYSHIRE
    Ratings:
    +257
    Thanks for your reply,

    I usually switch on the Dometic, press the A button, start the engine and set off.

    It normally runs off the engine until we arrive and then switches itself to Gas.

    We always run on gas when abroad as we mainly use the Aires and rarely use places with hook-up.

    It's only in this country that we use any hook-up at all as the fridge/freezer seems happier on gas and needs less 'bars' to work okay.

    When we arrived on the site in Lincolnshire last week after 2 and a half hours driving the freezer compartment was still warm with no obvious feeling of cold to the hand.

    I left it a few hours more but it still didn't cool at all.

    I tried both hook up and gas settings but there was no discernable drop in temperature.

    There was a pilot light on, the metal box surrounding it was hot, but it apparently didn't ignite whatever it's supposed to do.

    Until the third day - when it started to get as cold as it should have done earlier.

    The thermometer readings were spot on for both fridge and freezer after a few hours.

    :) :) :) :)
     
    • Like it Like it x 1
    • Thanks Thanks x 1
  4. Lenny HB

    Lenny HB Funster

    Joined:
    Oct 18, 2007
    Messages:
    15,046
    Location:
    On the coast in West Sussex
    Ratings:
    +24,652
    Acording to Keith's Profile he has a Pilote I think they use EBL's so if wired the same as German vans if switched to 12v and the engine is not running it will run off the hab batteries.

    Have you checked the flue is clean, although this normally has most effect on gas the electric elements are inside the flue and if it is well sooted up it may cause problems on all power sources.
    If the gas is lighting and it's not cooling that would look like it's the flue sooted up.
     
    • Like it Like it x 1
  5. tonyidle

    tonyidle Funster

    Joined:
    Aug 6, 2013
    Messages:
    6,547
    Location:
    Kendal, Cumbria
    Ratings:
    +8,975
    I've just had the cooling unit in mine replaced. The symptoms were that it worked perfectly for varying periods from 4 days to 2 months. When it failed all three power sources were fine and the bit of the pipework that should get hot did so. The control panel showed no fault. Leaving it off overnight would 'reset' it and it would then work for another indeterminate period. The Dometic specialist I took it to diagnosed the problem immediately as the cooling unit. His explanation is that a venturi inside the pipework blocks. Switching it off for a period allows the liquids inside to drain down clearing the venturi as they do so. He believes but has no way of proving it that poor quality tubing used in the manufacture of the cooling unit corrodes when the fridge is unused for long periods. My van had been unused for at least a couple of years prior to me purchasing it. The products of this corrosion block the venturi. Apparently Dometic now source their tubing from China.
     
    • Useful Useful x 2
    • Informative Informative x 1
  6. keithchesterfield2

    keithchesterfield2 Funster

    Joined:
    Oct 16, 2018
    Messages:
    61
    Location:
    CHESTERFIELD DERBYSHIRE
    Ratings:
    +257
    tonyidle – thanks for that.

    As I said earlier a Gas engineer I spoke to thought it might be the cooling unit.

    How much did it cost to replace and was it a job you could do yourself or did a Dometic engineer need to do it ?

    Lenny HB – the Dometic doesn't run off the leisure batteries when the ignition is off but I will see about cleaning the flue

    My worry is if the RMD 8505 is not diagnosed and repaired it may do the same thing again when we go to France later this year and it will then be even harder to get it sorted.
     
    • Like it Like it x 1

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice