Over the years I've had a few canisters where the lindel valve got stuck in the open position. That can be dealt with by leaving the stove on the canister. The only other obvious weak point is the o-ring gasket in the stove that seals around the valve. I actually noticed some minor wear on the o-ring of my stove over fifteen years ago. I bought a replacement o-ring and started carrying it, but never needed it.
So last weekend we're snow camping and the first canister finally runs dry. I swap in a new one and fire up the stove only to see a blue flame coming out of the side of the stove where it meets the canister. I kill the stove and douse the flame. It turns out it's the o-ring.
But the spare one isn't in the kit, it's with the other stove (we have two identical Gigapower stoves). Fortunately, when I re-mated the canister the chipped and torn o-ring squished together well enough to seal despite its rotten condition. The stove worked just fine! This saved us from either a very thirsty night or a long ski in the dark (for me) down down down to the last running water and then back up up up to our camp.
So a new o-ring for one of our twenty-something year old stoves. I'll make sure and have a spare with both in the future. And inspect critical gear more often (there's a promise I probably won't keep). In the few years I used my MSR stove I replaced numerous o-rings and gaskets and even an entire pump assembly. I don't miss it.
What else can go wrong with a canister stove?
