Optimus 80 safety valve

I am refurbing an Optimus 80 gasoline stove, and while I love the utility, it's easy to see that an overpressure condition could ruin your day. So I have a few questions. 1. As a practical matter, has anyone had a bad day with this type of stove? 2. Does anybody know at what pressure (psi) the safety valve in the filler cap is supposed to let go? And lastly, before I spend an hour with the grinder, where can one obtain the valve's 5 sided wrench?

Chris

 

Odd that there are no replies. I found some information in a climber's magazine article on this site. According to the article, these stoves operate at about 7-10 psi, the safety valve is supposed to release at about 65 psi, and the pressure vessel is tested to 100 psi.
The only mention of hazard is the rare occasion when due to excessive heating of the tank, the safety valve lets go, and a plume of flame is released.

Chris

 

@Trebleplink
hi

 

I am a newbie both to the site and to pressure stoves, but I started with wicked petrol stoves and quickly faced the same question about the safety release valve. I suspect the lack of response about the SRV in your Optimus 80 is because it's a touchy subject. Quite a lot has been written on this site about them, and in these litigious days it is a brave person who offers advice about something that could maim or kill if it goes wrong.

There is the "don't touch the SRV" camp with the very good reasoning that unless you have the equipment to make sure that the valve will release at 65psi exactly you shouldn't be touching it because, as you allude, you could have a really bad day if you get it wrong wrong in either direction. Moreover, it's not just you that could have a really bad day - at some point your stove will probably pass into someone else's hands and they will be unaware that the SRV has been fettled and will be assuming it is safe and will do it's job at the right pressure, until they have that bad day...

Then there is the "we don't have any choice" camp with the very good reasoning that you can't buy new caps and there's no company refurbishing the old caps with a guarantee that the SRVs are set correctly. You can buy replacement caps but they are, at best, new old stock and there's no guarantee that the pip or the spring in the SRV are still good, and therefore still no guarantee that the SRV will release at 65psi thus preventing a really bad day. Old pips can stick to the brass where they are sealing, and require considerably more than 100psi to release them, meaning your accidentally overpressured stove could turn into a brass hand grenade. Old pips can harden and old springs can corrode and release way under 65psi, thus your correctly pressured stove could suddenly have a plume of highly volatile petrol spurting out of the valve, and over you, right next to the pretty blue flame.

People have had bad days with these stoves, there are stories here and elsewhere. That said, there are not many stories compared to the vast number of stoves that are circulating since they were manufactured, but it only takes one, personal, story to seriously injure or kill you. Reading between the lines (i.e. this is my interpretation of what I have read, not a statement of fact) most people seem to view the SRV as a last resort that may or may not work as intended and they do NOT rely on it to keep them safe. Instead they monitor their stove like a hawk, follow all the instructions to the letter (e.g. no oversize pots), and don't try to push their stove to the limit. And keep a rusty bucket and a fire extinguisher handy at all time.

 

I’ve never worried about it. Cook with it outdoors and enjoy is my humble view. Of course, this applies only to myself.

 

It is written here so much, it is most likely someone not wishing to write a reply again.

There is more of a concern for those that use a stove without bothering to learn first.
There is much written here.

 

Do a search for the same on the Svea 123. There are many threads on the topic. The design is the same.

 

My experience. Have only had one old model 8 vent out the SRV, by then the tank was too hot to touch. I was only sterilizing lake water, two small pots worth. Can always pour water over the tank. Flame was only a few inches long. So much worry about a flame, the SRV is doing its job.
Duane

 

Sound advice- an enormous amount has been written about the 123 and Optimus 8R- there is a lot of crossover with the Optimus 80. A newcomer might well not be aware of this...