problem with flame

[welshdi]

Hi, please bear with me as this is my first post. Over the past few months I have had a problem with my torch.

I have a Nortel Mega Minor with an Oxycon generator and my propane is outside the property with the pipe fed through a hole in the wall into my workshop. Recently, when my oxygen is off and I have a flame which is propane only, as I slowly turn the valve to turn the gas off, sometimes the flame gets larger before it decreases and shuts off. This has only started since I fitted a new gas bottle and we had the cold weather this winter (-10 deg C). Also, sometimes when i have had a neutral flame, the flame fluctuates up and down by itself.

My husband has watched this happen several times and checked to make sure that I'm not turning the gas up by mistake, and this is not the case. He has also checked for leaks and everything is fine. My set up is only 18 months old and I'm concerned that this is a safety risk. He thinks it may be an issue with the regulator or the flash arrestor.

Has anyone else experienced this or know what the problem is?

Cheers, hope someone can help.

Di

[flame n fuse]

I'm not sure about this, but are the valves on the torch full on when this happens, or just part on? and is the valve on the propane tank on full, or part? Does the flame get A LOT bigger, or just a bit?

[Hamilton Taylor]

Hi, welcome to the forum!
This is probably 2 separate issues.
A pure propane flame, getting larger, then smaller, as you turn it down, is usually a result of the way the valve was machined - its not a problem, as long as the valve shuts off properly (without overtightening  - this will damage the valve seating).
A fluctuating neutral flame is usually the result of a pulsing oxycon output - check that the oxycon is set to something less than max output (eg around 4 on a 5lpm unit), and the problem should go away.
In any case, unless the variations are actually scary big (trust me, you will know...), these are minor annoyances which many of us who work in the cold, with oxycons, deal with on a regular basis.


Have fun!

Sean

[welshdi]

Hi, thanks for your speedy replies. 

Sounds like it's a common problem. I was getting concerned as this has only started happening during the winter. Oxycon is set to 4 so should be ok. Am wondering if I have been a bit overzealous and over tightened the valve on the torch but it still turns off ok. Hopefully no chance of the house burning down ,

Thanks again both will let you know how I get on in the future.

cheers di.