Well I thought I would post the outcome of my Bluestar 22K burner adjustment exercise because it shed valuable light on the process for me and I hope it will be useful for others who may attempt this. If anyone read my other thread you will see that I had previously tried to adjust the simmer on my bluestar burners and claimed, wrongly it seems, that the lowest flame was achieved by turning the simmer set screw to the end of its travel. At least that is what I THOUGHT I was doing. In that case it seems though, as Stooxie warned, that I was actually involving the movement of the main valve shaft too. Thus CLOCKWISE was raising my flame and ANTICLOCKWISE was lowering it. However going anticlockwise I seemed to feel an "end point" which I assumed was the low point of the simmer adjustment. Yesterday I decided to have another go at one of the 22K burners to see if I could get it lower as I had never reached the point reported by others where you go so low that the flames almost go out and the ignitors click. I inserted the screwdriver and as before clockwise raised the flame and anti clockwise lowered it. After talking with Mandy at Bluestar today I realize that even though I was pretty sure the valve stem was not moving in fact I must have been moving the valve stem to get those variations. Anyway, yesterday I kept on going, with more force, in the anti clockwise direction and that is when I felt like something gave way or stripped inside the valve and the flame got higher. Then I was just not able to get the flame back down to its previous level. Mandy told me to adjust the simmer while the valve is in the off position. Sure enough now I was able to turn the screw in the proper direction: CLOCKWISE to LOWER the flame and ANITCLOCKWISE to RAISE the flame (makes a lot of mechanical sense). It turns out that this adjustment was never possible for me before, I think because the set screw just was too tight and would not budge. Evidently my extra force in the anti clockwise direction must have freed up the screw but by that point I was still not able to get adjustment because I think the valve stem was moving easier the the screw. Today with the screw loosened and the valve in the off position I was now able to turn the screw clockwise, indeed until I had no flame at all in the low position!! So now I have adjusted the flame and it is actually much lower than my other 22K burner. After talking to Mandy I decided not to try to adjust the other one because that screw is definitely stuck: with the valve in the off position it will not turn clockwise. It feels like it would be easy to actually strip the head of the screw and so I think I will leave it as it is.
To summarize:
1. Although I thought I had adjusted all my burners a while back it seems that they were in the factory set position because the screws were quite tight and unknown to me I was actually moving the main valve slightly (thanks Stooxie - that is what you said!).
2. Applying extra force to the simmer set screw loosened it in the anti clockwise direction which is actually the flame raising direction. Presumably when I felt something "give" it was actually the set screw loosening.
3. In order to get the flame back to very low I had to turn the now loosened screw in the CLOCKWISE direction (but this was only possible with the main valve/shaft in the off position).
4. My now adjusted 22K is much lower than the other one which is at the factory preset position. However I don't think I will touch that one now for fear of stripping out the set screw. It is definitely not moving too well and Mandy said I would need a whole new valve if the screw head stripped....
5. Mandy also warned NOT to hold the valve shaft with pliers or anything while you adjust the set screw because it is possible to snap the shaft off that way....thankfully I did not do that.
So now I have two kinds of 22K burners: one with factory set low and one with "bossa" low. There is definitely quite a difference: If I put my hand over each burner I can get my hand much closer to the lower one before it feels uncomfortably hot. I was never actually that unhappy with the simmer before all this but I did find I had to move things back to the smaller burners quite often to finishi off stews etc with the longer cooking times. I think this newly adjusted burner will be very useful.
Sorry this was so long winded but I wanted to post it as a guide for others. Mandy, as always, was very helpful and many thanks to all who replied with help on the other thread.
thull