Vacuum Warning System

[Loogie]

Well, in my M20J my hi/lo vacuum warning system is still acting up, the lo vacuum flashed intermittently through the flight today, I finally pulled the warning system CB, and reset it, which made it go away for a while. We just changed the pump to a new one so I know it's not the pump.

I am planning on installing a vacuum gauge and disconnecting the hi/lo warning system. Anyone else gone through this? Seems just having a vacuum gauge will show you exactly what you are getting instead of a dummy light.

[N201MKTurbo]

I would check for leaks in your vacuum system. You could have a chafed hose with a hole in it.

[Loogie]

Yup will do that as well; good suggestion, my suspicion that it is the signal and not the vacuum, is because it is so intermitent, also if it was leaking when I reset the caution light it should have come back but it didn't, just a supposition though.

[Marauder]

My original was attached to the back of the DG. When it broke, I replaced it with a Precise Flight vacuum warning light.

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[carusoam]

The dummy light was a standard solution from the factory in the early 90s...

Adding a gauge is minor surgery. Not very costly.

From experience...

Don't try troubleshooting while flying. The leaking tube may turn into broken fittings.

I think my M20C MAP line broke that way...

If you go with a JPI, you can get a vac sensor. That's on my ten year goal list...

Best regards,

-a-

[RussG]

Just went through this same issue. The mechanic went through and it was a problem with the switch on the back of the HSI. He disconnected the high vacuum warning and calibrated the low vacuum side. Works perfect now. He said the high vacuum warning is ridiculous as the vacuum going low is the problem.

[Loogie]

Any suggestions of where to put the vacuum gauge on the panel?

[RussG]

Mine is down low by the flaps and cowl flap switches above the fuel tank selector. Flew this weekend and his fix worked. Now it flashes for low vacuum and the flickering annunciator is all gone.

[Hank]

Mine is up top, just above the gear switch. Let's see if I have a picture on the iPad.

[Marauder]

Mine is up top, just above the gear switch. Let's see if I have a picture on the iPad.

What is the gizmo attached to the gear wheel knob?

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[TTaylor]

I installed the 1" gauge in the upper left corner above the airspeed and left of the gauge cluster.  Easy to see and much better than Idiot lights.

[Marauder]

Now that I look at your panel some more... What the heck is the red button for? Also, it looks like your vacuum is running on the high side. Or is that parallax thing?

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[Hank]

What is the gizmo attached to the gear wheel knob?

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That's a thingy the factory was installing in 1970 to make it hard to "accidentally" move the gear. It must be pushed to the right before pulling the gear switch out a little and moving it up or down. It took several years before I could move the gear in either direction and not have this thing rock sideways and turn off the landing light. Very irritating coming into nontowered fields at night . . .

Now that I look at your panel some more... What the heck is the red button for? Also, it looks like your vacuum is running on the high side. Or is that parallax thing?

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That there red button in the glare down low is the push-to-talk button mounted on my yoke. And yes, vacuum has always been right at the high limit, which is good because in this photo it's running both an AccuTrac and AccuFlight system in addition to some gyros.

This is the only panel picture I have on my iThingy. I'll attach a yoke photo tomorrow; the button is in a metal plate sticking up off the lower left yoke arm, just right to press with my thumb.

[Marauder]

That's a thingy the factory was installing in 1970 to make it hard to "accidentally" move the gear. It must be pushed to the right before pulling the gear switch out a little and moving it up or down. It took several years before I could move the gear in either direction and not have this thing rock sideways and turn off the landing light. Very irritating coming into nontowered fields at night . . .

That there red button in the glare down low is the push-to-talk button mounted on my yoke. And yes, vacuum has always been right at the high limit, which is good because in this photo it's running both an AccuTrac and AccuFlight system in addition to some gyros.

This is the only panel picture I have on my iThingy. I'll attach a yoke photo tomorrow; the button is in a metal plate sticking up off the lower left yoke arm, just right to press with my thumb.

I thought I had seen everything Mooney put in a plane. That gear handle protector is a new one for me.

I recognized the PC button but couldn't tell from the picture what the red button did.

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[Hank]

Hah! Found the picture! It is a clear shot of the red PTT and the mysterious gear switch, in the Down position [the previous picture was with the gear Up]. This is my first Mooney, the only one I fly regularly, and the switch was like this before I bought her.

 

Does anyone else have this type of thing on their gear switch?

 

Apparently no one else has a permanently mounted PTT, either, preferring the wrap-around Velcro that gets in the way? I thought it was pretty clean, much better than the similar but different PTT mount on the right yoke [see tiny black button in second photo].

[Marauder]

Hah! Found the picture! It is a clear shot of the red PTT and the mysterious gear switch, in the Down position [the previous picture was with the gear Up]. This is my first Mooney, the only one I fly regularly, and the switch was like this before I bought her.

Does anyone else have this type of thing on their gear switch?

Apparently no one else has a permanently mounted PTT, either, preferring the wrap-around Velcro that gets in the way? I thought it was pretty clean, much better than the similar but different PTT mount on the right yoke [see tiny black button in second photo].

Very interesting... Wonder if others have that gear guard gizmo. Don't you need to pull out on the gear handle to move it?

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[Hank]

Very interesting... Wonder if others have that gear guard gizmo. Don't you need to pull out on the gear handle to move it?

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Finger the switch guard to the right (click! Off goes the landing light . . . Made a few dark landings before I caught on to that . . . ), pull the wheel-shaped knob out, then move it up or down. Remove hand, knob goes in and guard rotates left into place. Compare the two photos side by side; the Up position should be obvious (it's the one at 9500'; the one with zero airspeed is gear Down ).