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Author Topic: APU won't stay lit  (Read 654 times)

Offline airupthere

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APU won't stay lit
« on: March 16, 2017, 11:05:34 AM »
I've got my overhead partially wired, and I'm just tinkering, trying to light the APU. I hold the start switch down for about 5 secs, see the EGT coming up, and then when I let go of the start switch, the APU levels off, and then shuts off.

I don't have a left-Aft fuel pump running (but that's optional right).
I cant imagine it's fuel exhaustion because i wouldn't see the EGT go up if there was no fuel

I'm using prosim, and SIOC. The switch is the honeywell switch, and the guage is the Flight Illusion APU EGT.

Any thoughts about why the APU won't stay lit?

Thanks for the help in advance!!

Randy

Offline Trevor Hale

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Re: APU won't stay lit
« Reply #1 on: March 16, 2017, 11:23:38 AM »
I could be wrong here because I don't use prosim or SIOC.

However, in FSUIPC Land the switch has 3 positions

OFF, ON, Start

Pushing the start switch sets the bit to a 2.

Releasing the start switch sets it to a 1

turning it off sets it to a 0

you may be doing " Start 2 then stop 0"  (Needs to go to a 1)

May not be explaining it well, but this is what I am wondering..  If you hold the start switch on start forever will it stay running?

Also.. your right, Turning the Left Fuel Switch on, only makes it easier on the fuel pump in the APU.  Saves Maintenance, but not required.
« Last Edit: March 16, 2017, 11:25:42 AM by Trevor Hale »
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Offline KyleH

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Re: APU won't stay lit
« Reply #2 on: March 16, 2017, 11:31:03 AM »
Well there are a couple of things. Make sure you switch is wired and programed correctly. Use the ProSim Panel to see what is happening with the APU switch when you release it. You may have accidentally wired the center position to shut if off.

Offline Trevor Hale

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Re: APU won't stay lit
« Reply #3 on: March 16, 2017, 11:32:57 AM »
Yeah, what Kyle said ha ha ha.
Trevor Hale

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Offline airupthere

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Re: APU won't stay lit
« Reply #4 on: March 16, 2017, 12:51:10 PM »
haha thanks guys!! I'll check it out.. Mostly likely cause is just wired the switch wrong.. it does stay lit as long as I hold the switch in the start position. I'll keep the group posted.

Offline airupthere

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Re: APU won't stay lit
« Reply #5 on: March 21, 2017, 01:15:49 PM »
So I've checked my switch and it's properly wired.
I am using Prosim, and there are 3 switch inputs in prosim for the APU..

APU off
APU on
APU start

My switch in IOC is wired up for APU off, and APU start. There is no wired state for "on".

I have the variable definition set for APU off and APU start..
There is an option for APU on to be "system" but it has to be always on, or always off.. if it's always on, start doesn't work at all.

I'm also experiencing this with the ground power switch. when I switch to ON, and then it goes back to center, the ground power is cut off.

Thoughts? Is this just a prosim configuration problem? It acts like it doesn't interpret the momentary switch.

 

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