X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 27 May 2010 06:01:15 -0400 Message-ID: X-Original-Return-Path: Received: from iron7.midco.net ([24.220.0.83] verified) by logan.com (CommuniGate Pro SMTP 5.3.7) with ESMTP id 4327509 for lml@lancaironline.net; Wed, 26 May 2010 20:37:19 -0400 Received-SPF: none receiver=logan.com; client-ip=24.220.0.83; envelope-from=zoelt@sio.midco.net X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Ai0FAJZb/UsY3KSd/2dsb2JhbACBP4cylTJywWeFEwSDQg X-IronPort-AV: E=Sophos;i="4.53,307,1272862800"; d="scan'208,217";a="491443445" Received: from host-157-164-220-24.midco.net (HELO YOUR105B4D3942) ([24.220.164.157]) by out.vip.midco.net with ESMTP; 26 May 2010 19:36:43 -0500 From: X-Original-To: "'Lancair Mailing List'" References: Subject: RE: [LML] Re: Pressurization problem X-Original-Date: Wed, 26 May 2010 19:36:42 -0500 X-Original-Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0000_01CAFD0A.C4A61740" X-Mailer: Microsoft Office Outlook 11 In-Reply-To: Thread-Index: Acr8W1Agl3aBg/oWRpGMjI+ZoR/dAQA2F8gg X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 100331-2, 03/31/2010), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0000_01CAFD0A.C4A61740 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To all who replied. =20 Problem turned out to be a loose set screw in back of the = pressure(altitude) controller. Gear and static switches were wired out of the circuit so = never would have stopped pressurization any way. Once the controller travel = was adjusted and set screw tightened we could close the valve, initiate a = =BD psi differential at 1500msl and c ontroller set to 0. Unit functioned flawlessly in flight to 220 and rapid descent (1500-1800 fps). Thanks to all who responded. Tim =20 _____ =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of zoelt@sio.midco.net Sent: Tuesday, May 25, 2010 5:41 PM To: lml@lancaironline.net Subject: [LML] Re: Pressurization problem =20 Thanks Bob and everyone who responded. I=92ll post what I find out for everyone=92s education. Tim =20 _____ =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Robert Pastusek Sent: Tuesday, May 25, 2010 7:00 AM To: lml@lancaironline.net Subject: [LML] Re: Pressurization problem =20 Tim wrote:=20 Cabin won=92t pressurize. Visitor shopping for a 4P was sitting in = cabin with a battery charger on the battery supposedly studying the cheltons but I suspect he was pushing every button and switch he could. Now pressure = valve won=92t close. I can hear the dump switch and gear handle switch both clicking in the valve but it doesn=92t move up or down. Removed the = valve and checked for travel. I can manually close it on the bench but it = immediately opens again. With pressurized air flowing in (vacume cleaner hooked up = in reverse) I can depress the valve with my fingers and almost get it to = seal but it immediately opens. Is there another safety switch in the pitot system somewhere? Any idea where? I=92d appreciate any advice. Thanks, Tim, N524JG, LNC4P, Ser# 411 =20 Tim, Are you sure you by-passed the gear-down switch? That=92s the most = likely cause of =93pressurization dump=94 when the gear is down. You can test = this by pulling the hydraulic pump circuit breaker; then [CAREFULLY and = COMPLETELY] bleeding down the hydraulic system with the flaps. (You can add a safety factor by putting a length of 2x2 wood in the nose gear scissors.) When = the hydraulic pressure is zero, by-pass the gear down-lock solenoid and = raise the gear handle. Then test the system again. In my airplane (depends on = how the system is wired, but this is =93standard=94), the switch that = controls the down-lock also controls power to the pressure controller. Could a wire = have come off one side of this switch=85it=92s behind the left side of the = center vertical console, just below the gear operating lever. Your report of =93clicking=94 above would seem to have already validated this part of = the system, but worth checking twice=85) Sorry I don=92t have another = idea=85 =20 BE SURE TO GET THE GEAR HANDLE BACK DOWN BEFORE RESTORING POWER TO THE HYDRAULIC SYSTEM. =20 Bob ------=_NextPart_000_0000_01CAFD0A.C4A61740 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

To all who = replied.

 

Problem turned out to be a loose = set screw in back of the pressure(altitude) controller.  Gear and static = switches were wired out of the circuit so never would have stopped pressurization = any way.  Once the controller travel was adjusted and set screw = tightened we could close the valve, initiate a ½ psi differential at 1500msl = and c ontroller set to 0.  Unit functioned flawlessly in flight to 220 = and rapid descent (1500-1800 fps).

Thanks to all who = responded.

Tim

 

From: = Lancair Mailing List = [mailto:lml@lancaironline.net] On Behalf Of zoelt@sio.midco.net
Sent: Tuesday, May 25, = 2010 5:41 PM
To: = lml@lancaironline.net
Subject: [LML] Re: = Pressurization problem

 

Thanks Bob and everyone who = responded.

I’ll post what I find out for everyone’s education.

Tim

 

From: = Lancair Mailing List = [mailto:lml@lancaironline.net] On Behalf Of Robert Pastusek
Sent: Tuesday, May 25, = 2010 7:00 AM
To: = lml@lancaironline.net
Subject: [LML] Re: = Pressurization problem

 

Tim wrote: =

Cabin won’t pressurize.  Visitor shopping = for a 4P was sitting in cabin with a battery charger on the battery supposedly studying the cheltons but I suspect he was pushing every button and = switch he could.  Now pressure valve won’t close.  I can hear the = dump switch and gear handle switch both clicking in the valve but it = doesn’t move up or down.  Removed the valve and checked for travel.  I = can manually close it on the bench but it immediately opens again.  = With pressurized air flowing in (vacume cleaner hooked up in reverse) I can = depress the valve with my fingers and almost get it to seal but it immediately opens.  Is there another safety switch in the pitot system somewhere?  Any idea where?

I’d appreciate any = advice.

Thanks,

Tim, N524JG,  LNC4P, Ser# = 411

 <= /o:p>

Tim,

Are you = sure you by-passed the gear-down switch? That’s the most likely cause of “pressurization dump” when the gear is down.  You can = test this by pulling the hydraulic pump circuit breaker; then =  [CAREFULLY and COMPLETELY] bleeding down the hydraulic system with the flaps. (You can = add a safety factor by putting a length of  2x2 wood in the nose gear = scissors.) When the hydraulic pressure is zero, by-pass the gear down-lock solenoid = and raise the gear handle. Then test the system again.  In my airplane (depends on how the system is wired, but this is = “standard”), the switch that controls the down-lock also controls power to the pressure controller.  Could a wire have come off one side of this switch…it’s behind the left side of the center vertical = console, just below the gear operating lever. Your report of = “clicking” above would seem to have already validated this part of the system, but = worth checking twice…) Sorry I don’t have another = idea…

 <= /o:p>

BE SURE TO = GET THE GEAR HANDLE BACK DOWN BEFORE RESTORING POWER TO THE HYDRAULIC = SYSTEM.

 <= /o:p>

Bob

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