Morning guys. I've recently bought a Petromax 828 from Poland, lovely condition generally, but I'm having problems with the preheater. The tank holds pressure no problem, the main fuel valve and burner head seem to work fine, but I cant get the rapid preheater to light. It's blowing just air, no fuel mix/mist from it - anyone know the problem or the fix? Thanks.
The rapid preheater has a jet connected to the feeding tube that might be blocked. There is an additional connection to the air above the fuel to produce the air/fuel mixture. To clean the small orifices you will have to remove the upper cap of the jet, then you will be able to get to the fuel jet mentioned above. If it doesn't work you will have to check the fuel tube itself which might be blocked too. At the lower end there is a screen which might cause troubles. You will have to replace the lead seal that sits between preheater and tank.
OK thanks. Is cleaning the jets just a question of poking a wire down the holes? I don't have a lead seal so I'd like to try and fix it without dismantling unless I have no choice.
I've partially disassembled the lamp and can see the two tiny holes either side of the central cone, does the fuel come out of these holes? When I pump a little there is a hissing and the area does get some paraffin around it.
The small holes are the ones where the air that is in the tank comes through. When there is a little paraffin it means the feed tube might be ok. The paraffin comes out of the jet in the middle. The rapid pre heater needs a lot of pressure to work so assure that this is not the problem. During the pre heating process you will have to keep the pressure in the tank up because it uses the air from inside as described above. Edit: Corrected a wrong statement.
OK the jet in the middle is blocked then - I actually couldn't even see a hole. Air hisses plentifully from the two side holes when the tank is pumped up beyond the red line. But no fuel from the middle.
OK, try to free it with a pricker, usually they were sold together with the lamp but you still can buy these cleaning needles just in case you don't have one. I forgot to say that it might be possible to unscrew the whole pre heater because you can give the lead seal a second try. It is not as important to use a new one as it would be with the vapouriser because there the position of the wheel is adjusted by tightening until the direction is correct, the lead seal deforms accordingly and thus can only be used once.
Guys, I'm going nuts here. I dont have the best eyes in the world, but for the life of me I cannot see a central hole. I see two tiny holes either side of the central cone, but nothing in the middle. I even took a couple of macro shots... Please, just reaffirm? You are saying that at the top of that central cone there is a hole? It must be literally microscopic.
My understanding is that it's a VERY small jet. You really are just shooting vapor out with it. I have a special jet cleaning tool on the way, and the instructions are very deliberate that you should not attempt to clean the pre-heater jet with a main jet pricker.
Have a look at the photos on this website: Link In the first third of the page there is a photo of the jet. As Al said it is a special cleaning needle needed for those small holes.
I have an Optimus 1200, one of the brass ones selling on ebay right now. The preheater is not drilled-it's for looks only I guess. Maybe for the military-they usually don't want the rapid. Dan MacP
I think you're going to have to pull it out and find out where the fuel feed tube goes to. I'm pretty sure I've seen ones without a central hole (that work).
The last one I fettled had no central hole. Just he two you illustrate. Cleared them and it worked. ::Neil::
Remove the burner body as already recommended and unscrew the screen at the end. Try if air gets through, just blow in it. Clean the tube or the screen if necessary. If there is no central jet there must be a connection below the central cone where the fuel and the air get mixed. This seems odd to me because the mixing of air and fuel normally happens in the chamber that is build by the cap with the central hole that is already removed in the pictures. In my opinion the central hole in the burner body is missing due to a factory fault, sometimes there are jets found without hole too.
I took the lamp outside to try and get a better picture using sunlight... There is definitely no hole in that central cone and it is very different from the nozzle in the link. I guess I'm going to have to take it apart. BTW, the code on the base of the lamp is 0963.
The pre-heater pricker that I ordered arrived today, and BEHOLD, a hole appeared where there was none. It is a VERY FINE wire. Looking at the photo from your posting on the 4th, I'd say you have a clogged jet that would benefit from a proper poking.
