My rcp20 had a temp dial, for the common heater circuit, as sensed in the developer tank. There were two switches. One turned the whole unit on. The other you depressed, and the light in it came on if the heater was either on, or up to temp. I don't remeber which, but it was a way of not leaving any lights glowing all the time.
I now run a fujimoto CP-31. I empty it of chems and rinse it after every printing session, unless it is late and I know that I will be printing the very next morning. It goes into standby, and only turns the rollers one revolution every minute or so. This cuts aerial oxidation, and prevents crusties from forming on the rollers.
I use kodat RA-RT for ra-4 printing, and have had success if the chems have been lightly used, and replensihed appropriately running the chems for periods as long as 6 weeks if actully just running 5-6 sessions in those 6 weeks. That is with keeping the chems in glass when not in use in the machine.