Is it random? Or ash caking in the fire pot preventing the pellets from igniting? I don't clean after every cook either because I use drip pans most of the time, but I do check the fire pot occasionally to clear any possible build up in the fire pot.
In this example picture you can clearly see ash can cake up in the fire pot. That's why I check/clean the pot every few cooks or so. I've never experienced a random failure to ignite yet.
In this pic I had a flame out, due to a pellet void. The caking in the pot, while cleaning up, got my attention so I decided that was something I should keep an eye out for in the future.
I haven't figured out what causes the caking, but suspect it's pellet and/or humidity related. Most of the caking I see is close to the glow plug because it's the lowest point in the fire pot.
If I was a new SW owner this is something I would keep an eye on too.
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