Now that I have a five to six week wait for the chrome I need to decide how exactly I plan to control this brute. The machine originally was direct wired and the elements controlled on/off via a mercury actuated pressure switch. I have purchased a sirai pressurestat to replace the mercury switch but I am tempted to go a bit further. One option is fit a proper ON/OFF switch and also a PID controller with a SSR. If I do this I will retain the sirai for use as a overpressure shutoff prior to the pressure relief valve kicking in. Since the PID is used to control boiler steam temperature which in turns controls the boiler pressure is there any other advantage, apart from cost, in using a temperature element as opposed to a pressure transmitter. I have also seen similar machines where a level probe is fitted directly into the boiler sight glass and may go this way also.
