Another Primus 535

Discussion in 'Stove Forum' started by Snaf, Feb 25, 2020.

  1. Snaf United Kingdom

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    Hi all
    I've come across this forum whilst looking for info on the following stove. I live in Devon, UK.
    It's been in the family for decades but not used for maybe 15 years, it has run on meths in the past but I'm hoping to be able to restore it and use it with UK heating oil as I have a large reserve of it.
    Looking forward to reading through the forum and finding more info.
     

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  2. Afterburner

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    Looks that stove has 207 burners that can be converted to Meths and for Kerosene. I think that heating oil is (in UK is also) lower quality fuel than kerosene so it won't burn perfectly clean on those burners.

    Stove is easy to restore. Just clean it and then start to test various parts. First thing to check are the seals in tank cap and in NRV that is on bottom of the pump. Also check and oil the leather cup that is on pump piston. Once those are checked you can try if you get pressure into tank. Then you can test how burners work.
     
  3. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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  4. Simes

    Simes Subscriber

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    I'm on the way....
    28 sec kerosene (aka heating oil) is perfectly fine in stoves.

    Guide to Heating Oil - Understand Heating Fuels | Crown Oil

    There are slightly more refined versions available but at a cost.

    If your home heating is oil then once the stove is running you'll not be short of a cuppa in a power cut. :thumbup:

    Some of my neighbours here in Wiltshire say they have actually been to Devon. ;)
     
  5. Snaf United Kingdom

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    Thanks for input, I've ordered some new parts. Looks like I have a new hobby :-)
     
  6. Snaf United Kingdom

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    It lives, a quick clean up, new pump seal, unblock fuel tube on left hand burner fill with UK heating oil and fired it up. Left hand burner burned yellow for a while right hand seemed ok.

    I'll take some flame pictures when it's dark as todays bright sun seems to hide it in my pictures (any tips on flame pics?)
    IMG_20200229_1042403.jpg IMG_20200229_1042459.jpg IMG_20200229_1042485.jpg IMG_20200229_1045558.jpg
     
  7. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Is the Left-hand burner cap glowing red, or the burner “roaring”?

    If so it is just possible that your burner is suffering from “under-burn”, where the fuel mixture has been ignited and is burning under the burner cap.

    Under burn can soon melt and destroy an outer cap unless the burner is quickly extinguished.


    The way to avoid underburn is to never allow ignition of the flammable mixture under the outer cap.

    First, make sure the inner and outer burner caps are clean with no adherent rust or carbon flakes on their surface. If residues are on these surfaces they can glow once hot and cause early ignition of the air/fuel mixture. You should also check that the caps are properly seated on the burner so that no flame can slip under an edge.

    1. Pre-heat the burner with absolutely no fuel feeding to the burner.

    2. Allow the pre-heat flame to totally extinguish.

    3. Quickly open the fuel regulator valve a small amount.

    4. You should get clouds of white paraffin vapour/air mixture exit the many holes in the outer cap.

    5. Only now should you light this mixture with a match or flame applied above the outer cap.

    6. After 2-3 minutes of successful burn the burner will be hotter and you can increase fuel feed gradually until full power is achieved.

    7. If, on lighting, the burner immediately reverts to under-burn, Close the regulator valve, and start the whole process again.

    Best Regards,
    Kerophile.
     
    Last edited: Feb 29, 2020
  8. Snaf United Kingdom

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    Thanks, great info I was unaware of the possibility of under burning. I think it was just burning off some residual oil as I was over keen to open the taps, in the end it cleared itself and clean burned for 15 minutes with out the cap melting.
     
  9. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi @Snaf it is good that you have an innocent explanation for the difference in flame behaviour of your two silent burners and it has now corrected itself.
    Your stove has not experienced the dreaded under-burn this time. However, you now know about it and will be able to diagnose it and correct it in the future....

    You also asked about taking photos of burner flames:

    1. Use a tripod stand or stable surface to support the camera.

    2. Turn off the auto flash on your camera before taking any such photos,

    is the best advice I can offer

    Best Regards,
    Kerophile.
     
  10. Tony Press

    Tony Press Australia Subscriber

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    The result of underburn (Radius silent outer cap):

    5F47877F-5C43-461A-8F62-0FE10FA6D64E.jpeg


    Cheers

    Tony