Petromax 500 rapid lighter inoperative.

My Petromax rapid CP500 (from Egypt) has a malfunctioning rapid heater. When I open the cover and apply a flame, it just blows the flame out. There does not appear to be any paraffin coming out of the nozzle (which is a new one). I saw something about this in an operating instruction but I can no longer find it. Can anybody help, please?

Jim.

 

Hi Jim

Logic would say there is a problem with the rapid heaters 'draw' tube ! Maybe it's got a break in it between the top of the tank/rapid heater, and the level of paraffin

Just a thought

 

Hi,
there's not only the outer nozzle which can be screwed off like a cap. Beneath the outer nozzle there's the inner nozzle which has three orifices (or five, at the old ones): a central one which is connected to the fuel pipe, and also orifices near the rim, where air comes out. Further, there's a small mesh filter at the lower end of the fuel pipe.
To me it sounds that either the fuel pipe / filter or the central orifice are clogged, maybe by some dirt from the tank.
So remove the whole thing from the tank and clean it carefully. Don't try to remove the fuel pipe as it gets broken easily. At last you have to experiment a bit with the air pressure when lighting the rapid starter: some of them are a bit sensitive to this matter.

Regards, Martin

 

Hey! I did not know this, I had seen the 3 holes but did not know they were connected. Lunch now, then my siesta and then I'll be on it.

Thanks a million, Martin!

Jim.

 

Well done Martin

Every day's a school day here aye

 

No luck! I dismantled the preheater and cleaned everything in acetone in my ultrasound cleaner, put it all back together and- nothing. No paraffin coming up the tube. Dismantled and checked everything, filled the fuel tube and applied 1 atu pressure, paraffin squirted out in a nice straight jet. I could not find any way to dismantle the fuel tube except unscrewing the filter at the bottom, all clean, I pushed wire down the tube, it seems clean. Back in the ultrasound to make sure.

HELP!!!!!


Jim.

 

I would have thought acetone would be a bit aggressive in an ultrasound bath, particularly if there are (were!) rubber and plastic parts involved - not to mention the health and fire risks.

Just sayin'...

 

I used to work for NATO and we used acetone for many things, it never damaged anything or anyone (obviously don't deliberately breathe in the fumes, we had extractors) It cleans everything beautifully, you clearly need to remove anything it might dissolve but this does not apply to the Rapid pre-heater!

Jim.

 

Jim,

if all tubes/orifices are really free then there's no reason why it shouldn't work. After all the principle is not so complicated.

Before assembling the whole lantern (just keep the starter and the vaporizer and don't mount the globe cage) could you make sure that there's enough fuel in the tank (about 2-3cm should be there at least because the tube doesn't go down very far), and then pump it up outdoors and watch what comes out. There should be a real "spray" of fuel, not only air. Once you see the spray just try to light it, and if it gets blown out try at different pressure until it stays on.

Cleaning the whole thing in acetone wouldn't be a problem since there's no plastic. it removes old fuel residues very well. And an ultrasonic bath is what I also use to clean the parts. But I tend to use water with some citric acid, since this removes anorganic residues (such as oxides and rust) better.

When nothing else helps you could obtain a spare part e.g. from Hytta etc. (part No. 226 complete, or part No. 225 only lower part)

Good luck, Martin

 

Hi,
When you remove the filter simply blow air through the tube. Check what happens.
Btw you can unscrew the small fuel pick up tube.

 

Thanks, Wim, I'll try that and see what I find.

Jim.

 

I have checked it all again. The fuel tube is clear, there is a fine jet of paraffin when I begin to pump but it will not light?
I have cleaned all the orifices and adjusted the cover so that it will close off when I don't need to use it. I have tried to light at pressures from zero to 1.5 ATU, still nothing, I think I shall just use the alcohol burner to preheat, it works fine and the rapid is just a pain in the backside!


Jim

 

Jim,

Can you post pictures of the device ?
Are you 150% sure all the air holes are free ?
from what you write I am guessing you have no mixture only pure fuel. This means the air holes are blocked or you overfill the lantern.

The air holes take air from inside the tank so the buffer above the fuel.

 

No, Wim, I am sure the air holes are clear, I have pushed very fine wire through them , and through the fuel hole in the middle, blown compressed air (3Atu) through the whole thing, dismantled and assembled. There is air blowing through the top hole, that is what blows my lighter out!
I do not think I can take a useful macro photo which will show much!

Jim.

 

I agree, Wim!
First I thought there was too little fuel, but now it sounds opposite.
Jim, the tank takes about 1,25 litre of fuel at the max, level just below the filler cap, and never tilt the lantern at refueling. If it's filled too high then there will be no air for the rapid starter. If you open it it should look like a fine sray of paraffin. If there's only a fine jet then there's no air.
Regards, Martin

 

I have about 0.75 litres in the tank. I see a fine jet of paraffin From the centre hole with the nozzle unscrewed but not with it in place,I guess the paraffin should squirt through the two holes? At no point do I see a "fie spray" it is always a fine jet.There is a lot of air coming through, enough to blow out a cigarette lighter!
Maybe I should order the complete rapid pre-heater?


Jim

 

Is the outer nozzel fitted?

 

Outer nozzle needs adjusting relative to the inner until atomisation happens. Then it should deliver a fine mist.

Too far either way delivers excess air or fuel. I seem to recall it's a sensitive setting.

This assumes that the inner & outer cones are in good shape. Any burrs or scratches stop it working.

My original didn't work and the flip lid was missing so it was impossible to shut off.
It got a nitrile washer fitted between inner & outer nozzles until it could be replaced with a new assembly. New one works perfectly.

 

A simple picture of the device is enough. No macro or othe thingy.
I get the idea we miss something due to translation or missing parts.
Otherwise take a lokk here : http://www.petromax.nl/PX_datum.html , scroll down a little and see the different designs of the rapid.

 

Yes, I have fitted a new outer nozzle but it is screwed down tight onto the lower main body, I did not try to adjust it, I had to bend the piece which holds the pip in order that it closed the hole! This is probably the problem, I did not know that it had to be adjusted!

Jim.

 

I'm getting there! I dismantled the upper part of the lamp and unscrewed the upper nozzle, then screwed it down slowly while pumping (very fiddly!), At a certain point i had a mist of paraffin which I could light and produce the familiar pre-heat flame. The trouble was that the upper nozzle did not stay where I put it and screwed up or down, displacing the flip lid locating hole. The whole thing is unstable and cannot be set to a position where the mist is produced at all times. I looked at the diagrams but there is nothing there to lock the upper nozzle except when it is locked against the lower nozzle!
I'll try again tomorrow.

JIm.

 

To my knowledge there's no way to adjust the outer nozzle. It has to be screwed down until it sits snugly on the rim of the inner nozzle.

Should there be a gap it will cause an (air) leak when the lamp is in operation because the flip lid shuts only the central hole. Look at the pictures/drawings to see what I mean. The only way I could think of to get that sorted would be to use some PTFE-tape to seal the thread. But that's surely not what it was designed for.

So I can only repeat my suggestion to replace the whole thing (or at least parts of it), since it could be that there was a maintenance or production fault which now prevents it from correct operation.

Regards, Martin

 

Hello, Martin,
JonD says it needs to be adjusted and when I unscrew the top nozzle off the bnottom one, I get as fine spray, but it won't stay in the correct position. Looks a if I will have to buy a complete assembly to get a working one.

Jim

 

I'm glad you finally got some magic mist Jim!
As you say - getting there - but a shame you can't maintain the position of the parts. I see no reason why PTFE tape wouldn't work.

I wondered if there could be a fine O ring missing between the two but the Petromax exploded diagram does not show one...

The only preheater I have seen completely apart was "got at" so I wouldn't trust it to have correct components. On the new one I have never separated these parts so I don't know what is inside.

If I can get down the shed I might inspect it today to see.

 

As Martin says: there is no adjustment.

I get the idea that something is basically wrong. Therefore pictures ! please.

And since your lamp is from Egypt where they have almost the same repair skills as in India, there is also a possibility that you have a repaired/modified flame thrower.

 

Apologies Jim I haven't had a look at my working one yet and and it's pouring down here now. Really not the time to go looking in the shed.

I have looked inside the old one recently replaced as that is readily to hand. The outer nozzle is a loose fit over the inner. It would leak unless tightened right down. Any fine adjustment would be quickly lost, even if it didn't happen to leak.

This means the inner and outer cones must be machined to tight tolerances. Could it be mismatched parts in your case? I still suspect a shim washer of just the right thickness would allow it to atomise and spray a mist.

If a nitrile or viton washer of the right thickness could be inserted between the two it would become adjustable for optimum mixture.

In your shoes I would still try PTFE tape to see if this has any merit before buying a new one.
Sounds like fun!

If I had a tank that would mate with my scrap torch that could be tried - only in better weather than today!

 

I think you're right, Jon, a shim would do the trick, I have some brass shim material, maybe 2 thou, I'll try cutting some rings from it and fitting them (one?) between the nozzles, I think I could adjust the spacing by screwing them down tighter. It doesn't need a lot, I get the mist when it is just loose.
Thanks for the help, It is appreciated!

Jim

 

I am sure he is wrong. Sorry.
Why ? Well since taking pictures is hard I made some of a spare set with my phone.

You can clearly see the two air holes at the left, main body part. What you also can see or better imagine is that when screwing together the flat ring of the (right) cap will seal on the rim of the body part. This creates a chamber between the two and makes it possible to mix air and fuel by the venturi principle.

 

We'll see because there is nothing to lose.
A new one is Eur25 or so.

 

10,90 euro by Hytta...

(225) Anschlußkörper, komplett - 500 HK P-12409 7,40
(221) Düse, Rapid-Vorwärmer - 500 HKP-12400 3,50