Keith Freon

[MikeDelta]

Does anyone have an operation manual for the Keith Freon (690)? I can't seem to find it online and alas, in our documentation.

I am unsure of its operation and interaction with the standard ECU and electrical system. 

[donv]

It should be in the AFM supplements. If it's not, you really need to get one.

It doesn't interact with the standard ECU at all. You turn it on when you want colder air (or more cold air) than the bleed air system can provide, and you turn it off when it gets too cold. Turn it off above FL180 (not that you need it up there anyway).

As for the electrical system, you should be able to figure that out by looking at the circuit breakers, although the supplement (and the 337) should give you more information.

[MikeDelta]

Thanks. I figured as much. I took a look at the fuse box, but not yet with the circuit diagram in hand.
Was just thinking that it might be connected to the fact that I cant do series starts.

[donv]

That seems like it could be a possibility. So you don't have an AFM supplement for the Keith system? Legally, I'm pretty sure you're required to have that.

The 337 should also have some information, and once again, that should be in the AFM. Do you have that?

I might have an installation guide for the Keith system somewhere in my aircraft files-- I can take a look. But you should start with the 337 and AFM supplement. If you have neither, I would look in the logs and see who installed it, and call them (if they're still in business).

[donv]

I find that I run the fans more than the actual air conditioning compressor-- probably a function of my location.

However, flying into the sun, circulating the air a bit does seem to keep the cabin temperature a bit more even.