X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 29 Sep 2008 13:13:47 -0400 Message-ID: X-Original-Return-Path: Received: from smtp-ext-01.mx.pitdc1.expedient.net ([206.210.69.141] verified) by logan.com (CommuniGate Pro SMTP 5.2.8) with ESMTPS id 3190802 for lml@lancaironline.net; Mon, 29 Sep 2008 00:18:18 -0400 Received-SPF: none receiver=logan.com; client-ip=206.210.69.141; envelope-from=rpastusek@htii.com Received: from dlhtpax009 (static-71-178-198-10.washdc.fios.verizon.net [71.178.198.10]) by smtp-ext-01.mx.pitdc1.expedient.net (Postfix) with ESMTPSA id EE87F7C090 for ; Mon, 29 Sep 2008 00:17:41 -0400 (EDT) Reply-To: From: "Robert Pastusek" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: RE: [LML] Door seal 4P X-Original-Date: Mon, 29 Sep 2008 00:17:38 -0400 Organization: Holmes-Tucker International, Inc. X-Original-Message-ID: <042501c921ea$4ff57500$efe05f00$@com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0426_01C921C8.C8E3D500" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AckhjetiFRUSL1uNQgSXUZLkooiHSwAV4b+A Content-Language: en-us This is a multipart message in MIME format. ------=_NextPart_000_0426_01C921C8.C8E3D500 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Ralf asked: I am wondering if I should move my pump and the pressure switch for the door seal in the door (Lancair IV-P). What would be the best way to get the electric power in the door - should I run a cable from the door to the fuselage or should I go with this switch that makes contact when the door closes. I would need 4 wires (2 for the pump and 2 for the switch). My door seal pump is mounted on the door, and I recommend this method for several reasons. Lancair now sells a small, high quality (and priced accordingly) pressure pump that fits much better than the old-style pump. Consider investing in the new pump if you use this. Mount the manual seal control valve in the door as well, and use an SUV sliding door-type pair of contact buttons to transfer power/ground to the door. I actually used three-button units on my IV-P so I could also operate a "DOOR UNLOCKED" warning light via a third lead that is closed to the common ground when either door latch is open. Whether you use the warning light circuit or not, install a fuse or CB in a lead from your primary/main power buss and then directly to one contact button. Run this lead through your door seal pressure switch and then to the pump. Run a ground to the other button and then from the button to the pump. Theory of operation: When the door is open, no power can be applied to the pump in the door (contacts open). Any time the door is closed AND the power buss is hot, the pump can be energized. If the door seal control valve (toggle switch) is in the off/vent position, the pump stops as soon as it builds pressure in the short piece of line between the pump and the control valve (assuming you have correctly installed the pressure switch between the pump outlet and the seal control valve). When the door seal pressure switch is on, air is diverted into the door seal until the set pressure is reached, and then the pump turns off. My system works well and provides a "built in" test of the pump/circuit each time I close the door, as the pump runs for a couple of seconds (unless it's been closed too recently for the pressure to leak down). Not necessary, but installing a one-way check valve between the pump outlet and the pressure switch allows the pump to "unload" between periodic starts to maintain seal pressure-if you have any leakage in the system. Hope this helps. BOB ------=_NextPart_000_0426_01C921C8.C8E3D500 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Ralf asked:

 

I am wondering if I should move my pump and the pressure switch for the = door seal in the door (Lancair IV-P). What = would be the best way to get the electric power in the door – should I run = a cable from the door to the fuselage or should I go with this switch that makes contact when the door closes. I would need 4 wires (2 for the pump and 2 = for the switch).

 

My door seal pump is mounted on the door, and I recommend = this method for several reasons. Lancair now sells a small, high quality (and priced accordingly) pressure pump that fits much better than the old-style = pump. Consider investing in the new pump if you use this. =

 

Mount the manual seal control valve in the door as well, = and use an SUV sliding door-type pair of contact buttons to transfer = power/ground to the door. I actually used three-button units on my IV-P so I could also = operate a “DOOR UNLOCKED” warning light via a third lead that is = closed to the common ground when either door latch is open. Whether you use the = warning light circuit or not, install a fuse or CB in a lead from your primary/main = power buss and then directly to one contact button. Run this lead through your = door seal pressure switch and then to the pump. Run a ground to the other = button and then from the button to the pump.

 

Theory of operation: When the door is open, no power can = be applied to the pump in the door (contacts open). Any time the door is = closed AND the power buss is hot, the pump can be energized. If the door seal = control valve (toggle switch) is in the off/vent position, the pump stops as = soon as it builds pressure in the short piece of line between the pump and the = control valve (assuming you have correctly installed the pressure switch between = the pump outlet and the seal control valve). When the door seal pressure = switch is on, air is diverted into the door seal until the set pressure is = reached, and then the pump turns off. My system works well and provides a = “built in” test of the pump/circuit each time I close the door, as the pump runs = for a couple of seconds (unless it’s been closed too recently for the = pressure to leak down).  Not necessary, but installing a one-way check valve between the pump outlet and the pressure switch allows the pump to = “unload” between periodic starts to maintain seal pressure—if you have any = leakage in the system.

 

Hope this helps.


BOB

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