gas soot clogged

Discussion in 'Tech/Mech General' started by Microchip, Aug 30, 2015.

  1. Microchip

    Microchip Funster

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    Dometic fridge will soot up the exhaust every 3 or 4 days.
    I've stripped it down cleaned and reassembled and all ok for another couple of days, including the small jet.
    Also recently replaced the thermal coupler.
    Any ideas or clues greatly appreciated
    Keith..
    .
     
  2. old-mo

    old-mo Funster Extra Special Life Member

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    Make sure the rig is 100% level... when running on gas..

    A soot ball will build up if the little flame touches the side of the chimney and eventually build up so big it will fall off and may block the jet..
     
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  3. Microchip

    Microchip Funster

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  4. Microchip

    Microchip Funster

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    Thanks old mo I'll level the van a bit better to see if gets better...
     
  5. funflair

    funflair Funster Life Member

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    Clean the airways to the burner but after the jet, I poked a drill through all the holes by hand and then blew it all with a can of compressed air, I had cleaned the flue twice before this action and both times it sooted in about a week.

    Ps we are always level thanks to E&P.

    Martin
     
  6. Microchip

    Microchip Funster

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    Thanks Martin, I'll strip it down again and give the air ways a good clean.
    Keith..
     
  7. Traveller_HA5_3DOM

    Traveller_HA5_3DOM Read Only Funster

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    Soot is a sign of poor combustion of the gas. It should burn with an electric blue flame when pressure and air mixture is correct. It could be down to someone cleaning the jet and using something that has enlarged the orfice. Never use anything other than an air line or a bike pump. It can also be that if you have filled up or used continental gas bottles you get various mixtures of propane/butane mixture according to seasonal adjustments that some countries make to cope with cold weather. Try a new jet 1st and make sure that the jet assembly lines up correctly with the heat exchanger block.
     
  8. funflair

    funflair Funster Life Member

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    Hi Keith

    And the chimney as well (I imagine you would) I pushed a bit of scothchbrite through our with some old flat twin and earth cable.

    Martin
     
  9. Microchip

    Microchip Funster

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    Well, I've cleaned everything, but not enlarged the jet size, made sure all assembled level and correct and it's still the same problem, it does stop if I leave the baffle out.
    So being here in cognac France there's not much more I can do other than as said by Traveller replace the jet assembly when I get home in 3 weeks time.
    Thanks for all the help given..
    Keith...
     
  10. tonyidle

    tonyidle Funster

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    Check the air intake hole in the diffuser (the hole or holes close to the jet outlet) is/are clean.
     
  11. TheBig1

    TheBig1 Funster Life Member

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    autogas and propane in some countries contain some other contaminants which leave a greasy black deposit in the flue. if you sniff the flue outlet, it shouldn't smell like burning plastic. with some propane sources it does and thats when you see rapid sooting of the flue
     
  12. Microchip

    Microchip Funster

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    I've got Gaslow fitted so you could be right Thebig1. But a new jet needed first to prove it is the gas.
    Keith.
     
  13. Microchip

    Microchip Funster

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    Not been able to get spare jet, I've had to adjust size my self.
    So, dismantle the jet assembly from the flue stack and then strike up gas, to see size of flame, it was way too big, so dismantle the jet to find it was out of shape, using an Allen key flat end placed inside of the small jet and gently hit with small hammer which put the jet back into its correct shape, reassembled and test the flame, now it's a nice small bluflame put it all back together and bingo still OK 4 days later. But will buy a new jet on when home
    Keith
     
  14. Traveller_HA5_3DOM

    Traveller_HA5_3DOM Read Only Funster

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    Well done for sorting it out whilst away particularly in foreign country. Could well have been the previous person who 'serviced' it that enlarged and then damaged the jet on reassembly. In the good old days the jets were brass with a thread that fitted a bike pump for cleaning it. There was a number stamped on the side to indicate the jet size. Now a feeble bit of ally that they tell you to change every time you bring a spanner within a few centimetres of it. Progress:- it is just the opposite.
     
  15. Microchip

    Microchip Funster

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    Thanks Traveller, I carry a few spares, water pump, gas regulator etc. But a spare gas jet is one a bit ott.
    As you say the modern stuff is made on the cheap hence my problems I guess.
    Still 3 more weeks to go, hope it lasts
    Keith..
     
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