X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 30 Mar 2014 10:22:50 -0400 Message-ID: X-Original-Return-Path: Received: from vms173007pub.verizon.net ([206.46.173.7] verified) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTP id 6805625 for lml@lancaironline.net; Sat, 29 Mar 2014 16:09:00 -0400 Received-SPF: pass receiver=logan.com; client-ip=206.46.173.7; envelope-from=lancair403@verizon.net Received: from self87aab97f5d ([unknown] [71.176.58.154]) by vms173007.mailsrvcs.net (Sun Java(tm) System Messaging Server 7u2-7.02 32bit (built Apr 16 2009)) with ESMTPA id <0N3700H7WRXRBJ80@vms173007.mailsrvcs.net> for lml@lancaironline.net; Sat, 29 Mar 2014 15:08:17 -0500 (CDT) X-Original-Message-id: <75E0616A4B9A4B9C840EA80440F13BE4@self87aab97f5d> From: "William Rumburg" X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] VMS1000 pressure gauges on LNC2 X-Original-Date: Sat, 29 Mar 2014 16:08:07 -0400 MIME-version: 1.0 Content-type: multipart/alternative; boundary="----=_NextPart_000_0024_01CF4B69.12E6F950" X-Priority: 3 X-MSMail-priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 This is a multi-part message in MIME format. ------=_NextPart_000_0024_01CF4B69.12E6F950 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Nick -=20 The VMS1000 obtains oil and fuel pressure by exciting the transducers = with 5VDC and they return a 0 - 50 mVDC signal that's linearly = proportional to pressure. You almost certainly have the = originally-supplied Honeywell Media Mate transducers. Someone here on = the LML might have direct knowledge of their internal construction, but = I believe they're an older moving-bellows design. If your pressures are = otherwise functioning normally, it's difficult to image the problem as = anything other than a sticking bellows. While not really a problem -and = something you can live with- a modern, high-quality Measurement = Specialties transducer is an excellent replacement = http://www.meas-spec.com/downloads/US300.pdf Bill Rumburg N403WR (Sonic bOOm)=20 ----- Original Message -----=20 From: Nick Long=20 To: lml@lancaironline.net=20 Sent: Friday, March 28, 2014 4:02 PM Subject: [LML] VMS1000 pressure gauges on LNC2 Hello All, I=E2=80=99ve got a Lancair 320 and we=E2=80=99ve just re-installed the = engine and are in the process of the annual inspection. Both the fuel and the oil pressure readings on the VMS1000 display are = very strange. The fuel pressure gives a reading when there is no = pressure and the oil pressure reads very low. A quick check with some = old steam gauges suggests the actual pressures are about right. The = pressure sensors are both in the engine bay, fed with flexible hoses. Is this likely to be the pressure sensors? Do they tend to misbehave? = Is there an easy way to check them? Or could it be in the wiring or the = display unit itself. I can=E2=80=99t see anything in the VMS1000 manual = about calibration. Any help gratefully received. Thanks, Nick ------=_NextPart_000_0024_01CF4B69.12E6F950 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
Nick -=20
 
The VMS1000 obtains oil and fuel = pressure by=20 exciting the transducers with 5VDC and they return a 0 - 50 mVDC signal = that's=20 linearly proportional to pressure. You almost certainly have the=20 originally-supplied Honeywell Media Mate transducers. Someone here on = the LML=20 might have direct knowledge of their internal construction, but=20 I believe they're an older moving-bellows design. If your = pressures=20 are otherwise functioning normally, it's difficult to image the problem = as=20 anything other than a sticking bellows. While not really a problem -and=20 something you can live with- a modern, = high-quality Measurement=20 Specialties transducer is an excellent replacement  http://www.meas-spe= c.com/downloads/US300.pdf
 
Bill Rumburg
N403WR  (Sonic bOOm) 
----- Original Message -----
From:=20 Nick Long=20
Sent: Friday, March 28, 2014 = 4:02=20 PM
Subject: [LML] VMS1000 pressure = gauges on=20 LNC2

Hello All,
 
I=E2=80=99ve got a Lancair 320 and we=E2=80=99ve just = re-installed the engine and are in=20 the process of the annual inspection.
 
Both the fuel and the oil pressure readings on the VMS1000 = display are=20 very strange. The fuel pressure gives a reading when there is no = pressure and=20 the oil pressure reads very low. A quick check with some old steam = gauges=20 suggests the actual pressures are about right. The pressure sensors = are both=20 in the engine bay, fed with flexible hoses.
 
Is this likely to be the pressure sensors? Do they tend to = misbehave? Is=20 there an easy way to check them? Or could it be in the wiring or the = display=20 unit itself. I can=E2=80=99t see anything in the VMS1000 manual about=20 calibration.
 
Any help gratefully received.
 
Thanks,
 
Nick
 
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