Fuel valves

Can anyone explain what this picture is trying to convey?

Taking the fuel from the port tank and returning the unused fuel to the port tank. Which is what you want to do - return the fuel to the tank it is being drawn from.

What is missing is the ability to draw from both and return to both and the ability to transfer between both. Not necessities, just nice to have if balancing the boat.

menzies said:

Taking the fuel from the port tank and returning the unused fuel to the port tank. Which is what you want to do - return the fuel to the tank it is being drawn from.

What is missing is the ability to draw from both and return to both and the ability to transfer between both. Not necessities, just nice to have if balancing the boat.

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How can that be corrected?

If he draws from Port tank and returns to Starboard tank, that will transfer excess fuel to starboard tank... Or vice versa.

Depending on the engine, returning to the opposite tank might work well, or in the case of a Lehman 120, hardly at all.

But with Lehmans, it is easy to keep fuel loads balanced at 2 to 3 GPH as long as you fuel up with balance in mind.

Are they not both pictured in the OFF position?

-Chris

ranger42c said:

Are they not both pictured in the OFF position?

-Chris

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That's what threw me. Thought they were both off when actually they are both on to the port. Supply and return both going to port. I think we've figured it out.

It looks like originally the valves were either selecting Port or Starboard. Then someone wrote on and off with a marker. That is what is confusing to me. The valves are probably on all of the time, just either on to port or on to starboard. I don't see how they could be off in any position unless one of the tanks are disconnected.

Turner said:

That's what threw me. Thought they were both off when actually they are both on to the port. Supply and return both going to port. I think we've figured it out.

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We are all making guesses, so I will as well.

I think what happened was that when the valves were initially installed over that piece of wood or starboard, the positions for the Port and Starboard tank were written on the board. They were correct. With that type of valve handle, the direction of the pointer indicates which way it is open, not the direction of the long handle.

At some point, the PO was confused and made a guess based on his ignorance of how those valves work. In the photo you provided the fuel is drawn from the Port tank and returned to the Port tank. It appears that your setup will allow you to draw from one tank or the other and feed to one tank or the other. Normally you will draw and return to the same tank. However as Menzies mentioned, there are times when you may want to draw from one and return to the other if you need to rebalance fuel more quickly. However, this is dangerous if you happen to forget. You can end up with an expensive fuel spill.

In short, I can see where you could have been confused if you have not seen that type of valve handle before. You also assumed that the markings were correct. In this case, the initial markings were but the later On/Off markings were written by an uniformed and unfortunate PO.

Folks, both are on. The large side of the switch is the handle - there is a little arrow point on the other side showing what is on.

menzies said:

Folks, both are on. The large side of the switch is the handle - there is a little arrow point on the other side showing what is on.

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You said it clearer and with a better economy of words than I did.

dhays said:

We are all making guesses, so I will as well.

I think what happened was that when the valves were initially installed over that piece of wood or starboard, the positions for the Port and Starboard tank were written on the board. They were correct. With that type of valve handle, the direction of the pointer indicates which way it is open, not the direction of the long handle.

At some point, the PO was confused and made a guess based on his ignorance of how those valves work. In the photo you provided the fuel is drawn from the Port tank and returned to the Port tank. It appears that your setup will allow you to draw from one tank or the other and feed to one tank or the other. Normally you will draw and return to the same tank. However as Menzies mentioned, there are times when you may want to draw from one and return to the other if you need to rebalance fuel more quickly. However, this is dangerous if you happen to forget. You can end up with an expensive fuel spill.

In short, I can see where you could have been confused if you have not seen that type of valve handle before. You also assumed that the markings were correct. In this case, the initial markings were but the later On/Off markings were written by an uniformed and unfortunate PO.

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Thumbs up!!! I think you nailed it!

I think the OFF pos at 10 o'clock that's scribbled out refers to the flow path is blocked if the little pointer is in the arc from 9 to 12 o'clock. I would remove the added on off markings and restore the OFF at 10 o'clock.

Comodave said:

It looks like originally the valves were either selecting Port or Starboard. Then someone wrote on and off with a marker. That is what is confusing to me. The valves are probably on all of the time, just either on to port or on to starboard. I don't see how they could be off in any position unless one of the tanks are disconnected.

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If you move the marker to the word "off" the valve takes from neither port or starboard and is in fact "off".

These are three position valves, one feeding from the port tank, one the starboard tank and the third position closed.

"At some point, the PO was confused and made a guess based on his ignorance of how those valves work."

When you get it figured out repaint the diagram so there is Never confusion , the next owner will thank you.

I would investigate further to make sure of the meaning of the handle positions. May need to disconnect lines and suck/blow through them to verify. You want to be absolutely certain how the system functions and it could be either the sharpie or the original marks that are right.

Does this help ?

Only because the only ones I have seen are 180 degree sweeps...

Are there 3-way valves that function within a 90 degree throw?

RB

Hi RB,

The valves that I posted have a 360 degree sweep. It looks like I have put you crook - sorry mate . I thought that the mounting hole location and handle looked very similar to your set up and it looked to me that the board that they are mounted on had screws protruding to act as a stop against the handle.

BJ

Turner said:

How can that be corrected?

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Of course things get even more confusing if/when you install a fuel polishing system

Take the cover off and look at the actual valves and hoses.

Is there another set of valves just like this somewhere else in the boat?

My guess is that these are simple on / off valves that control the hoses connected to the Starboard tank. When the arrow is pointed at the word “Port”, the hoses to the Starboard tank are closed and the engine is running on the port tank. If I’m right, there has to be another set of valves to control the port tank.

Possum came with four valves just like this. I could draw / return to both tanks at the same time. I could draw / return to either tank. Or I could draw from one tank and return to the other.

Reading all this; I'm reminded of the John Denver fuel valve fatality.

diver dave said:

Reading all this; I'm reminded of the John Denver fuel valve fatality.

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Having seen his actual aircraft after the accident and studying it at Monterrey Naval Post Graduate Safety training, what exactly is the point concerning his error as I know the probable answer?

psneeld said:

Having seen his actual aircraft after the accident and studying it at Monterrey Naval Post Graduate Safety training, what exactly is the point concerning his error as I know the probable answer?

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Poor human factors in the fuel management design. But, as you well know, there is usually not just one cause for these things.

yep, poor design and......

...zero familiarity with his new aircraft, lack of training, and an out of sight valve were the reasons the Navy experts summed up.


Hardly an issue for a reasonably intelligent boater hopefully.....

yep, sad. Never flown a rutan design, but these are "stall resistant". Was there research on why an engine out would head it at high descent speed? Back when I had to worry with this, all the fuel valves were in front of me and well marked;

Roamer Blue said:

Only because the only ones I have seen are 180 degree sweeps...
Are there 3-way valves that function within a 90 degree throw?

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The seachoice valve photo is a typical L ball drilling with 360 handle so 4 possible configurations. Left, right, none, or both. T drillings are also available as are 180's.

https://www.directmaterial.com/knowledge/3-way-ball-valve-work/

So, this is a shot i took from a GB42 last week. Twins plus gen and i submit even without a lot of marking its pretty clear. Of course u can add a placard or two on the hazards of pick up and return on different tanks.





But no, I can't explain the 45 deg handle. Not my boat...

diver dave said:

yep, sad. Never flown a rutan design, but these are "stall resistant". Was there research on why an engine out would head it at high descent speed? Back when I had to worry with this, all the fuel valves were in front of me and well marked;

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his fuel valve if I remember was behind his head on the left.....thus the inadvertent engine shut down because he couldnt see it and not enough experience with that particular aircraft.....

because I wasnt involved in the actual investigation ..nor did I read it....and it is third hand info from an accident investigation class...my pass alongs are just that.....not fact...

The valve folks sell dual valves that switch the supply and return at the same time.

No confusion .

KISS