Hi Mike,
I was lucky that there were two identical thermocouple amps (AD595) on the board, so I could compare working with not working.
I tried shorting the input to the amps, but the suspect one stayed at 1.9 volts output. I changed the IC with a spare - no improvement. Checked the supply at the IC pins and the 5 volts was spot on, but the ground was at +1 volt. Checked the ground "daisy-chain" wiring and found a bad connection between the good IC and the suspect one. It was best to put a new ground wire in rather than re-solder the existing one.
With the new ground wire, the ground volts at the suspect IC was practically zero and the system now gave the correct temperature. It was the first fault in the controller in the five years since it was built - I hope its not a forerunner of future problems.
The U.S. Navy Fletcher Class (
http://en.wikipedia.org/wiki/Fletcher-class_destroyer ) used separate superheater boilers, which are exhaustively described here ....
http://archive.hnsa.org/doc/destroyer/steam/sec06.htm.
If you look on page 58, Section (c) there it is described when not to use the superheat boiler, plus all the bell signals from engineering to the boiler room - it makes you appreciate the automation that we have now.
I hate to think of these poor boiler operators having to respond to the directives from engineering and remembering, under battle conditions, which valve and sequence to operate - any mistake and you could wreak the superheaters and be a sitting duck to any passing Jap sub or Kamikazi - I suppose that was the "job" incentive scheme!
The only precaution regarding high temperature steam, that I can think of, is that of maintaining steam flow through all the superheater tubes to prevent them failing under high temperature. The other problem is with the turbines - too high a temperature and rapid temperature change, you risk expansion and blade rubbing - too low a temperature and you risk water carryover and blade damage.
I've never had experience of reversing turbines apart from seeing the "tiny" one on HMS Achilles many years ago. You could see it only had a couple of stages from its length.
All the best
Ian