From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [LML] IV-P Cabin Air System
To: lml
Date: Mon, 02 Dec 2002 23:13:32 -0500
Message-ID: <web-1893260@logan.com>
In-Reply-To: <NCBBKKMDBDCIKLFDJIOOMEJIDPAA.rpastusek@htii.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Content-Transfer-Encoding: 8bit

Posted for "Bob Pastusek" <rpastusek@htii.com>:

I have not researched this as fully as I should, but I understand that the
Dukes Controller works just fine in normal mode without a vacuum source;
that the vacuum source is only used to fully open the control valve during
"emergency pressure dump." I initially intended to install the suction port
of a door seal type pump to the Dukes controller and run it only when the
emergency dump switch is activiated, but have since elected to vent this
vacuum port to the external (unpressurized) air and not install a vacuum
source at all. My rationale is that the cabin pressure will bleed off very
quickly even without opening this valve. The only disadvantage I could
determine is that you lose the ability to vent significant air through the
dump valve. I thought that depressurizing the door seal would achieve the
same or better venting capability. As this is mostly speculation on my part,
I'd really appreciate any words of wisdom on the subject.
Thanks,
Bob Pastusek

>>>I am building a IV-P with an all electric panel. The Dukes cabin pressure
control valve requires vacuum to operate, as I understand it, during at
least any low differential cabin to outside air pressure periods.<<<