Seneca IV Vacuum removal with deice boots

[Tokirbymd]

Vacuum/boots help- for those with boots that have removed a vacuum system for glass panel. Did you cap off the line to the AI/HSI gyro instruments(item 12 on the Piper service manual) and keep the rest of the system intact? If so, what happened to the panel vacuum gauge and the master caution panel vacuum warning light? We are looking at removal of all vacuum flight instruments but have deice boots (Seneca IV). The installer says the AI is a required instrument in the vacuum line to keep the pressures and gauge accurate. But another mechanic says with the vacuum manifold that all you have to do is cap off the lines to the old gyro instruments. I can see where capping the line to the panel instruments would keep the air pump/vacuum intact, but wouldn't you lose the panel vacuum gauge? What about the master caution panel?

 

[Bell206]

What about the master caution panel?

I've never done this mod but if using an STC for the glass panel alteration it would seem the STC would address these questions otherwise where would the approval come from to alter the boot/vac system?

 

[Tokirbymd]

I've never done this mod but if using an STC for the glass panel alteration it would seem the STC would address these questions otherwise where would the approval come from to alter the boot/vac system?

The Aspen dual Pro Max STC allows removal of the vacuum instruments but doesn't address the effects on the deice system which is also driven off the vacuum and a pressure pump. The older Aspen install kept the vacuum AI and electric TC or in my case electric AI as backup. However we switched to the Pro Max and I would like to gain the panel space from the backup vacuum AI for an engine monitor so we are looking at options to move or remove this. The service manual and IPC are not very helpful in this regard, thus hoped someone here had been down this road before.

 

[Tom J]

Just went through that with a Chieftain, PA31. Dual Aspens on the left, single on the right, only kept vacuum pumps for the boots. We wound up tying the hoses together, and putting a cap on the suction line with a hole in it as a restriction. Piper support was no help, as the avionics are not theirs. The vac gage, with the configuration we did, reads ~4 in HG at idle, and gets to about 5.5 at 2200 RPM. 5.5 @ 2200 is what the book calls for when adjusting the regulator. Again, all for the PA31.

 

[mondtster]

If you're looking for a factory installation to reference you might look at how the newer Malibu Mirages are set up. Despite being 100% glass they still have vacuum pumps to control the pressurization and deice equipment.

 

[Clip4]

Just went through that with a Chieftain, PA31. Dual Aspens on the left, single on the right, only kept vacuum pumps for the boots. We wound up tying the hoses together, and putting a cap on the suction line with a hole in it as a restriction. Piper support was no help, as the avionics are not theirs. The vac gage, with the configuration we did, reads ~4 in HG at idle, and gets to about 5.5 at 2200 RPM. 5.5 @ 2200 is what the book calls for when adjusting the regulator. Again, all for the PA31.

Sounds like you are introducing unfiltered air to the pump.

 

[3393RP]

Just went through that with a Chieftain, PA31. Dual Aspens on the left, single on the right, only kept vacuum pumps for the boots. We wound up tying the hoses together, and putting a cap on the suction line with a hole in it as a restriction. Piper support was no help, as the avionics are not theirs. The vac gage, with the configuration we did, reads ~4 in HG at idle, and gets to about 5.5 at 2200 RPM. 5.5 @ 2200 is what the book calls for when adjusting the regulator. Again, all for the PA31.

Sounds good, the proper size restriction worked well, and leaving the vacuum gauge so the system can be monitored is important.

 

[TiltOn22]

Vacuum/boots help- for those with boots that have removed a vacuum system for glass panel. Did you cap off the line to the AI/HSI gyro instruments(item 12 on the Piper service manual) and keep the rest of the system intact? If so, what happened to the panel vacuum gauge and the master caution panel vacuum warning light? We are looking at removal of all vacuum flight instruments but have deice boots (Seneca IV). The installer says the AI is a required instrument in the vacuum line to keep the pressures and gauge accurate. But another mechanic says with the vacuum manifold that all you have to do is cap off the lines to the old gyro instruments. I can see where capping the line to the panel instruments would keep the air pump/vacuum intact, but wouldn't you lose the panel vacuum gauge? What about the master caution panel?

Wondering if you found any resolution. Just installed dual GI275s on a Baron 58 with boots and the vacuum pump has sheared at the spline twice. We took the line that was going into the instruments and ran it to the suction gauge and have the other line vented to the atmosphere.

 

[Tokirbymd]

Wondering if you found any resolution. Just installed dual GI275s on a Baron 58 with boots and the vacuum pump has sheared at the spline twice. We took the line that was going into the instruments and ran it to the suction gauge and have the other line vented to the atmosphere.

We ended up keeping the vacuum ai and moving it to the copilot side so everything would still work. I read of another similar plane that eventually had to put a vacuum instrument in 6e line and leave it behind the panel to keep everything working correctly.