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Source for Orifice

Zman
Zman Member Posts: 7,009
Hi all,
I am having trouble with a Dometic RV fridge that runs poorly at altitude. The manufactures solution is to not to run it on propane at altitude. That simply won't work as I really only camp off grid at high altitude.

In the past, I have brazed orifices closed and then re drilled them to a smaller size. This particular orifice seems to have glass in the nozzle so I am not very optimistic about that technique. I would also like to save the original in case I take the rig to the beach.

The threads measure 8mm diameter and 10mm long. From experience and adjusting the tables to compensate for ~35% less air density, I am thinking I need one around 63 to replace the 58 it came with. I can always redrill larger if needed. I will of course be performing a combustion analysis :D .

Does anyone know of a source for random orifices like this? Other thoughts?


"If you can't explain it simply, you don't understand it well enough"
Albert Einstein

Comments

  • hot_rod
    hot_rod Member Posts: 15,066
    Can you buy a spare #53. Might try and epoxy that opening and redrill?

    Or orifices.com :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Zman
  • Zman
    Zman Member Posts: 7,009
    Hey, there's no such thing as orifices.com (there should be though) ;)
    I would think that epoxy would melt? I could try and if it did not work I could drill everything out and braze it shut that way. The OEM orifice is expensive and hard to find. I would need to find a backup before I tried anything. It is camping season after all..
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot_rod
    hot_rod Member Posts: 15,066
    Buy an 8mm brass bolt, take it and the current orifice to a local machine shop, that's and easy build on a lathe. Take a handfull of bolts and drill for various altitudes :)

    You could almost do that with a drill motor and a file :) Or drill motor and bench grinder. Chuck the bolt into the drill, file or grind away away part of the hex to get the rounded shoulder where the burner attaches.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Zman
    Zman Member Posts: 7,009
    It's funny you said that. I was just looking at my drill press and scratching my head. ;)
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    mattmia2
  • Zman
    Zman Member Posts: 7,009
    Argh!, The caliber says it is 8mm but it does not match any 8mm threads.
    I am going to buy the OEM orifice and Frankenstein it...
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • mattmia2
    mattmia2 Member Posts: 4,007
    standard 8mm bolts are 1mm pitch, right?
  • mattmia2
    mattmia2 Member Posts: 4,007
    edited July 2020
    looks like a standard m8 is 1.25mm pitch

    but look for manufacturer names on the valve and other controls, they must have bought it from someone.
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 15,445
    Tunstall has orifices.
    Retired and loving it.
    Zman
  • unclejohn
    unclejohn Member Posts: 1,751
    There is a "orifice.com" it's on the dark web. A friend told me.
    ethicalpaulZman
  • Zman
    Zman Member Posts: 7,009
    @unclejohn
    I'm not sure that is the kind of "orifice" I had in mind :/
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein