fed up of the sundstrand!!

[Jacsac]

Hi everyone I have a recently bought tc840 and have had to replace my sundstrand 2 times in 100hrs and Im fed up. Ive herd that the schiff system is even worse and the only real option is the Enviro system. I wanted to know if anybody knows of a used Enviro system that I could buy, or hear some of your experiences
thanks
jack

[donv]

Personally, I like the Sundstrand. Mine has been great, but I realize that I have been both lucky and maybe well suited for it. I live in a fairly cool climate (Pacific Northwest) without a lot of humidity, and I have a Keith Freon system in my airplane. So my Sundstrand has a pretty easy life compared to one, say, based in Florida or Louisiana or somewhere.

I am also religious about adding oil at 25 hours (per the AFM) and never, ever, ever, ever, ever using Max Flo.

Have you gotten yours overhauled, or did you buy a used one? If it was overhauled, who did it?

If you want to give up on the Sundstrand then Enviro is the only real choice.

[Jacsac]

 I got it overhauled by Sundstrand twice, and have been checking the oil rigorously and having read the posts never used the Max Flo.  But yes my airplane is usually in California / Mexico or near the beach. I do use the Keith ac and it works ok. Im really happy with everything else and Love the performance !!!  Do you know of any used Enviro systems, since a new one is totally out of my budget!!

[Jacsac]

pic of the sundstrand

[Adam Frisch]

How much is overhaul, if you don't mind me asking?

[Jacsac]

Don’t know if I got ripped off but 25k

[donv]

Who really overhauled it? I don't think Sundstrand supports these any more, so it wasn't them. Maybe these guys?

http://www.koolairtechnology.com

They look like they know what they are doing.

[donv]

Also, how much was the Enviro to install? I think much of the cost is labor, so I'm not sure that used parts would make much of a difference. You already have the freon, so that's a big cost saving.

Schiff is not an option, do not even go there.

[Bruce Byerly]

The ACM failure is often just a symptom of other issues, which, if left unaddressed, lead to imminent failure of the fresh overhaul. CCU isn’t an option. I have an enviro in stock. Actually 2 of them.

[Adam Frisch]

I think the Enviro is $120K to install. Numbers from a  few years back, so might be even more today.

I have heard the Sundstrand performs OK, when its oil is changed every 25hrs, like Don said. But maybe that's just hearsay.

Aviation, sigh.

[donv]

What are the other issues? I assume in the overhaul the anti-ice valve is looked at and cleaned? And of course the filters are changed?

The ACM failure is often just a symptom of other issues, which, if left unaddressed, lead to imminent failure of the fresh overhaul. CCU isn’t an option. I have an enviro in stock. Actually 2 of them.

[Bruce Byerly]

From a plugged up heat exchanger to intermittent regulation and temp control, those things will eat themselves.  And if you’re climbing out in full cold and feel/hear it vibrate, don’t be surprised when it shucks an oil seal.  Take the plane to a service center who knows about them and go through it all.

[donv]

In addition to the heat exchanger, there were also some service bulletins in the 1980s for improved cooling of the unit where they added an additional air scoop on the fuselage. But I would assume any airplane still flying with a Sundstrand for this long would have that bulletin installed.

I couldn't agree more with your recommendation of taking it to a service center that knows about this stuff and getting it gone through. Much cheaper in the long run.

[Bruce Byerly]

I was just a kid but I remember putting scoops on and then taking them off. It didn’t fix the problem. Enviro has always been the best answer and the factory knew it, that’s why a large number were converted under warranty/factory support.  Unfortunately a few planes have been cobbled up by that other system. I just received a call from the FAA about that.  Sounds like a mess.

[donv]

The Schiff thing is definitely a mess. I know Aero Air has removed at least two Schiff systems.