Question on the Hybernite Rainout control tube

[runcyclexcski]

Hi all --

In case anyone here uses the Hybernite Rainout control system (a standalone tube with a heater in it), do you happen to know if it runs a feedback loop that maintains the tube at a setpoint (e.g. 37C), or is it an "always on" heater? It is not clear from pictures online whether the ACDC brick just has 2 leads for 12V/2A, or if it has an additional lead for a sensor (the latter would indicate that is runs a feedback loop). If the Hybernite Rainout does not have thermostat, are there standalone tubes on the market that do?

Thank you in advance!

[big_dave]

I used to use the Hybernite years ago, when I was using the Resmed S8 Autoset II. It is either on or off, with no temperature control. I only used it the cold half of the year, and switched to standard tubing the warm half of the year. I've read reports of people connecting it to a rheostat to lower the heat, but I never tried it.

[runcyclexcski]

Many thanks, big_dave! I also found from a blogpost that the ResMed heated tube has 4 pins two of which are for a 10kOhm thermistor and the other two are for power. Thus, it should be possible to make a PID loop with that one, in principle.