Hi all, wondering anyone has experience disassembling the preheat torch on a Primus 1321 or similar model? Mine has a packing leak but I so far have not been able to take the head off the torch nor pull the whole assembly from the fount. It's really in there and I can see the top of the fount flex when I try to turn either, even after heating. Looking for any advice so I can get it running. Thanks.
Do you mean that it is leaking in the box? In that case you don't need to remove the entire heater. You just need to remove the lever and box nut if you need to repack it. Sometimes it's enough to just tighten it up. Originally it use a graphite packing. I attach an image of one I have disassembled. It might help you to understand what you need to loosen and what you don't, and how it all work. Mind you, the cylider shaped little graphite packing is not the correct. I just placed first best there for illustration. It should in reality be about half the length of that one. As you can see, the thread into the tank is tapered, so the whole burner can be pretty tight. Especially if someone has had it all removed earlier, and then screwed it all almost a full extra turn in order to get it to seal and still align the flame tube correct. But it should come loose. Heating is seldom any good for loosening these. Unless it's the tank you heat, but I wouldn't recommend that because of all soft soldering everywhere... The two small screws on the side give you access to the air channel and the fuel channel respectively. Both end up inside the tank (the fuel pickup is of course under the fuel level, but the part for the air enter high inside the preheaters base. And here's the illustration from Primus patent. It gives a better idea of what's actually going on inside the thing...
Thank you for the diagram. I believe what you're calling the box nut I would call a packing nut and yes, it leaks out of there down the valve stem. I cannot get that box nut loose. Very tight and it seems to be deformed to a odd size where a 10mm doesn't fit but a 12mm could easily slip. It should be a simple repair if I can get it apart.
Yes, what you call packing nut is the same as the manufacturer call box nut. I can't remember which size this nut is, but why not try a 11mm if 10 doesn't fit and 12 slips? Or perhaps a 7/16 if 11 just barely doesn't fit.
Why didn't I think of that?? Kidding, I of course tried an assortment of box end wrenches without a perfect fit. The space is too tight to fit a small crescent wrench in as well. Everything felt as if a slip and rounding of the nut was immanent.
Aha. Since you specifically said that 10 didn't fit, but 12 slipped, I assumed you never tried 11. It would have been more "natural" to say that 11 didn't fit but 12 slipped... Never mind. The one that are 12 mm is the inner nut. I assume you already have removed the outer nut (the box nut)? That one is size 8 mm, and if that one isn't removed first, the inner one will of course stick. How about a picture of your preheater so we know how it looks?
Guess I'm not metric compliant. I I cannot remove the outer nut as the handle gets in the way. I do not see what to do to remove that. Away for the weekend so can look more closely Sunday.
OK. You still need to take the lever (handle) off if you are meaning to unscrew the whole thing. If you have the same kind of lever as in my picture of the disassembled torch above, you just simply remove it by firstly loosen the actual lever by turning it anti-clockwise. This is done with the aid of a spanner at the hex nut you can see just where the red bakelite ends. Once you have loosened this part, the lever is freed of the spindle, and should be easy enough to remove. Now when the spindle is exposed, it's just to firstly loosen the small packing nut, and then the larger one if you think it's needed. It shouldn't be. All you need to do after removing the packing nut, is to fill the area with a suitable packing. Originally it was a small sleeve or tube of pretty solid graphite, but you can also use any kind of graphite you got. Even crushed 'lead' from a pencil. Or perhaps Nils' trick with plumbers (PTFE) tape that you have rolled to a string, and then inserted as many loops you kan fit and still get the packing nut to enter. Here's a lever removed from the spindle to give you some idea of how it is constructed as both a lever and a lock against the spindle (which goes in the round hole of the "banjo fitting"):
Aha, there is the picture I needed. I just assumed it was all one piece. I will try that once we get home Sunday. I encountered trouble then put it on hold to avoid wrecking anything. Thanks.
Thanks for the help. I was able to get the torch valve stem assembly removed, replaced the old and damaged packing with graphite impregnated rope, and reinstalled. No leaks. Now, when I open the orifice up all the way by turning the tip cleaner full down, I get a tremendous pulsing with fireballs. I believe this is the infamous Leidenfrost Effect. I suppose I need to reassess the generator contents and add something to slow the passage of fuel. Thanks again for the help thus far.
I thought so. Just wanted to make sure. On the other hand, it's not impossible that a former owner have converted it to run on kerosene. Have you checked the jet and if the air restriction still is inside the air tube? If all still is correct, I think you are on the right track to add something inside the generator. A brass or SS mesh rolled around the cleaning needle rod is an easy fix that might do the trick.
It is behaving identically to a H.C. Lanterns burner I have. That one did not have a shred of packing in the generator when I got it. I believe it demonstrated the Leidenfrost Effect with unvaporized fuel passing rapidly through the generator and into the burner. I added some rolled brass screen to the generator and it burns beautifully now.
