X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 23 Jan 2006 01:50:41 -0500 Message-ID: X-Original-Return-Path: Received: from [216.148.227.153] (HELO rwcrmhc12.comcast.net) by logan.com (CommuniGate Pro SMTP 5.0.7f) with ESMTP id 941575 for lml@lancaironline.net; Sun, 22 Jan 2006 23:21:47 -0500 Received-SPF: none receiver=logan.com; client-ip=216.148.227.153; envelope-from=rpastusek@htii.com Received: from boblaptop2 (pcp09273488pcs.arlngt01.va.comcast.net[69.143.137.39]) by comcast.net (rwcrmhc13) with SMTP id <2006012304204901500gsih9e>; Mon, 23 Jan 2006 04:20:49 +0000 From: "Robert R Pastusek" X-Original-To: "Lancair Mailing List" Subject: RE: [LML] X-Original-Date: Sun, 22 Jan 2006 23:22:28 -0500 X-Original-Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_005E_01C61FAA.B61CA5F0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Importance: Normal In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_005E_01C61FAA.B61CA5F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Craig Blitzer wrote:...after a few minutes at altitude, the door seal pump light comes on and stays on. I pull the breaker, light of course goes out indicating pump off now. I do not loose the door seal because there is no increase in noise at whatsoever and I can hear the door seal deflate after I land. I am assuming that the seal is staying inflated during flight because of the one way valve that is installed. Any ideas why the "little bit" of pressurization I am maintaining would cause the door deal pump to want to come on and stay on? Craig, a couple of thoughts: You should be able to hear the seal pressurization pump running--this should correspond to the light if the system is wired IAW the builder's manual (You didn't specify, so I assume you're talking about an IV-P. I don't know how the other pressurized airplanes are configured.) It's possible that the pump will continue to run even with the seal inflated if the pressure switch is defective, you have a small leak, or the switch is set to too high a pressure. This is easy to test with the plane on the ground and the engine off. If the pump won't shut down, check first for leaks, then for a defective pressure switch. The switch is actually a "differential pressure" switch, so it's at least theoretically possible for it to work "normally" on the ground, and to not shut down at altitude because it can't achieve the required differential pressure. Unlikely malfunction, but possible. It's also possible that your pump is marginal on achieving the required pressure output--again unlikely, but possible if it's been run for a long time. This can be checked by hooking it up to a direct-reading gauge. My bet is that you have a small leak in the system. If the seal stays inflated until you flip the switch to deflate it, I'd look first in the line/connections between the pump and the check valve, but the whole system needs a good leak check; that's the most likely--and easiest to find--malfunction. Hope this helps! Bob Pastusek ------=_NextPart_000_005E_01C61FAA.B61CA5F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Craig Blitzer wrote:...after a = few=20 minutes at altitude, the door seal pump light comes on and stays = on. I=20 pull the breaker, light of course goes out indicating pump off = now. I=20 do not loose the door seal because there is no increase in noise at = whatsoever=20 and I can hear the door seal deflate after I land. I am = assuming that=20 the seal is staying inflated during flight because of the one way valve = that is=20 installed. =20 Any ideas why the "little bit" of pressurization I = am=20 maintaining would cause the door deal pump to want to come on and stay = on?

Craig, a couple of thoughts: You should be able to = hear=20 the seal pressurization pump running--this should correspond to the = light=20 if the system is wired IAW the builder's manual (You didn't specify, so = I assume=20 you're talking about an IV-P. I don't know how the other pressurized = airplanes=20 are configured.)

It's possible that the pump will continue to run even = with the=20 seal inflated if the pressure switch is defective, you have a small = leak, or the=20 switch is set to too high a pressure. This is easy to test with the = plane on the=20 ground and the engine off. If the pump won't shut down, check first = for=20 leaks, then for a defective pressure switch. The switch is actually a=20 "differential pressure" switch, so it's at least theoretically possible = for it=20 to work "normally" on the ground, and to not shut down at altitude = because it=20 can't achieve the required differential pressure. Unlikely malfunction, = but=20 possible. It's also possible that your pump is marginal on achieving the = required pressure output--again unlikely, but possible if it's = been run for=20 a long time. This can be checked by hooking it up to a direct-reading = gauge.=20

My bet is that you have a small leak in the = system. If=20 the seal stays inflated until you flip the switch to deflate it, I'd = look first=20 in the line/connections between the pump and the check valve, but the = whole=20 system needs a good leak check; that's the most likely--and easiest to=20 find--malfunction.

Hope this helps!

Bob Pastusek

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