The T3-BB series will be a good candidate for the project, there’s a new option which allows you to wire in 1k Pt inputs along with the usual universal input ranges.
Another option is a T3-Nano for the user programming plus a T3-12Pt expansion module which has precision electronics dedicated to 1k Pt type sensors.
For programming the system, its won’t take long to whip up a program for the heating system since you have the sequence already well defined in your existing system. It will mean porting it over to the ‘control basic’ of the T3 controllers but that should not take more than five or so minutes per control point.
The number of programs is limited to 16 @2k each, that’s a lot of program space considering the T3 maxes out at 128 outputs. If you need more you could consider adding another T3-nano which at $38 is a bargain for what it does.
There’s a en effort under way by Brent Bell to get node-red running on Temco hardware, his work is shown here.
Here’s where Brent is now, working up a user interface for several thermostat zones along with some lighting control.
It would be great to hear how you make out integrating with Open Hab, we’ll support you well.