Bruce, will these guys no longer overhaul the Sundstrand?
http://www.koolairtechnology.com/
Or is it just not cost effective, in your view?
Don, you can get it overhauled, maybe, but we are seeing total pricing above $40k to fix some units and get them working. That's almost half the current cost to convert to enviro (assuming plane has freon) which eliminates the cooling turbine. On top of the expensive turbine and expensive regular filter service and unpredictable lifespan, there are other key components which are no longer serviceable. The Sundstrand works great, provides ample cooling and heating. While there was historically a case to make the two systems almost a toss up all things considered, with the current pricing and issues, it's become a real problem unfortunately. Just keep the oil up and checked, the mx done, and hopefully yours will last forever.
Oh, and if you ever get a rumble coming from the back of the plane, turn up the heat quickly! You probably already know this tip. I mention it because I believe many failures are precipitated by improperly functioning anti-ice valves or sensors and when it rumbles, it's iced up and out of balance which cannot be good for the oil seals.
