A German-made heat and refrig. system outboard of a large 6-color sheet-fed press controls the temp of the h20/glycol coolant circulated in the press.
The PLC that controls all this has gone brain-dead and is quoted at ~10K to replace. Owner simply wants cooling function (it's N. California, so no sub-0 temps to worry about) and the simpler the better. A simple thermostat with remote sensor would do the job.
Contactors for compressor & fans are standard 24vac or 120vac stuff. Refrig circuit has lo- and hi-press switches which can be incorporated to shut everything down if need be. Coolant (glycol) circuit has flow sensor switch so to protect pumps if level goes to zero. All this "safety" stuff can be incorporated with little trouble. Regarding temp control, I've looked in Grainger's catalog but everything I see is ambient air type thermostat or remote-bulb type sensor. Are there controllers that use electrical (ie, 2-wire) sensors that can be bolted in place of the existing ones in the coolant plumbing (the existing ones are of unknown origin and will probably be incompatible with any aftermarket controller)?
Any suggestions helping me find a thermostatic controller for this application would be greatly appreciated.
Thanks, Sparky