Thanks for the reply, I didnt know the symbol for a pot. Duh!
I got the controllers from Farnell online. They cost me just under $3.00 Australian each.
For my thermostat I have a 100k NTC thermistor.
Triac = BT137 500
I want a set point of 32C.
I would like a multiturn potentiometer for the set point adjustment.
Load of the heating cable is 300 Watts.
I will try to work out the values for all the other components now.
If I get stuck can I swap you some ic's for more advice?
cheers and thanks again
luke