I have found cool mechancal pyrometer from Frank W Murphy Ltd ( http://www.fwmurphy.co.uk/ ) and it's nice there are pyro switches too available - http://www.fwmurphy.co.uk/pdf/ys6335.pdf - Elecrical switch what reads mecanical pyrometer temps and switches something
Single pyrometer and pyro-switch 030-058(-1) gives a possibility to place two control means to switch in or off something in different temps.
So - thinking abouth making a automatic, what switches in lesser temp water injection in and when temp raises then another control switches propane injection off.
Problem = Pyro switches are not adjustable (I must know what are the temps to order switch right)
Question = What is the bigger EGT what SD33T can tolerate without damage ? (long time/shortly)
And opinion on switching temps ??