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Thread: Javelin Tank Problem (O&N/Griggs)

  1. #1

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    Javelin Tank Problem (O&N/Griggs)

    Hello,

    I have a 182B that is having some issues with the Javelin / O&N / Griggs 18 gallon aux tank on the floor of the baggage compartment.

    The pump control switch is 3 position - off, on, and a spring loaded "start" momentary action position that is supposed to be held for 10 seconds to start the pump. When released, the switch springs back to the on position and the pump should continue to run.

    Problem is, the pump only runs when held in the start position. When released, the pump on light extinguishes and the pump shuts down. It doesn't matter how long or how many times you hold it in start. I can, however, hear the pump running when the switch is held in the start position (when testing it without the engine running).

    Secondly, the fuel tank drain/sump sometimes stops draining even though fuel is in the tank. It is very strange and just depends on the day...sometimes it will drain a few cups then stop, sometimes it will work normally, other days it won't drain anything.

    Thirdly, the tank only seems to hold about 16 gallons maximum (maybe this is normal?).

    Is there anything I can do to troubleshoot this or is time to break out another thousand for an A&P?
    Last edited by Narwhal; 10-20-2020 at 12:08 PM.

  2. #2
    wireweinie's Avatar
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    You should check our standard consultation rates before asking, lol.

    Sounds like there is a pressure switch somewhere ahead of the pump. When you hold the switch 'on' it allows the pressure to build, which turns on the pressure switch, which in turn keeps the pump powered on. When you suck air, the switch opens and shuts the pump off. You'll need to find the pressure switch and troubleshoot it. Also check for the possibility of air in the lines not letting the pressure switch close.

    We take cash, checks, Visa and Mastercard . . . .

    Web
    Life's tough . . . wear a cup.
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  3. #3

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    Quote Originally Posted by wireweinie View Post
    You should check our standard consultation rates before asking, lol.

    Sounds like there is a pressure switch somewhere ahead of the pump. When you hold the switch 'on' it allows the pressure to build, which turns on the pressure switch, which in turn keeps the pump powered on. When you suck air, the switch opens and shuts the pump off. You'll need to find the pressure switch and troubleshoot it. Also check for the possibility of air in the lines not letting the pressure switch close.

    We take cash, checks, Visa and Mastercard . . . .

    Web
    Thanks, I had to have some skin work done which involved removing the javelin tank earlier this summer. Pump/tank was working fine before that. Problem started after the reinstall, but the shop is not an easy place to get to, and I foolishly did not test the tank's functionality before departing the area....
    Last edited by Narwhal; 10-20-2020 at 12:22 PM.

  4. #4
    wireweinie's Avatar
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    In that case, make sure it was wired right on re installation.

    Web
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  5. #5
    wireweinie's Avatar
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    I have the wiring diagram for this system. Let me know if you need a copy. It seems like a fairly simple set up.

    Web
    Life's tough . . . wear a cup.

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    I was with Matt Griggs today and with regard to your problem his answer mirrored what Web has already said namely pressure switch and wiring. He can be reached at 570-499-0651 or 570-836-5757 if needed.
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  7. #7

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    Wow, thanks to the both of you! I will give this info to the A&P that maintains our aircraft, at least he should have something to solid to work off of now! I would probably create more problems than I solved were I try to address this problem alone as a mere pilot. Thanks again!

  8. #8

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    Quote Originally Posted by wireweinie View Post
    You should check our standard consultation rates before asking, lol.

    Sounds like there is a pressure switch somewhere ahead of the pump. When you hold the switch 'on' it allows the pressure to build, which turns on the pressure switch, which in turn keeps the pump powered on. When you suck air, the switch opens and shuts the pump off. You'll need to find the pressure switch and troubleshoot it. Also check for the possibility of air in the lines not letting the pressure switch close.

    We take cash, checks, Visa and Mastercard . . . .

    Web
    Hey Wirewinnie, I would be interested in the part number of the pressure switch (or a similar switch for a 12V system), I have been trying to figure out a system for a cub belly pod tank that I could "switch on and forget" and this might be the best solution.

  9. #9
    wireweinie's Avatar
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    If you want the exact part number of the pressure switch in this system, you'll need to contact Griggs Aviation at the numbers in post #6. But be aware that that system also uses an orifice, downstream of the pump, in order to keep pressures higher for the pressure switch. So if you want to use a pressure switch,keep in mind, simple head pressure is extremely low (usually less than 1 psi).

    I've seen three ways to automatically control the pump; pressure sensing like the above system, flow sensing, and timers. Flow sensing uses an impeller wheel such as the transducer in a fuel flow system to monitor the movement of fuel through a line. Good system but fairly expensive. I've also set up timers that run for specific time and then shut off power to the pump. If the operator wants more fuel moved, he actuates the timer and it runs again.

    These are the common choices and you'll have to decide which one is best suited for you. Let me know your thoughts about this.

    Web
    Life's tough . . . wear a cup.
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    Quote Originally Posted by wireweinie View Post
    If you want the exact part number of the pressure switch in this system, you'll need to contact Griggs Aviation at the numbers in post #6. But be aware that that system also uses an orifice, downstream of the pump, in order to keep pressures higher for the pressure switch. So if you want to use a pressure switch,keep in mind, simple head pressure is extremely low (usually less than 1 psi).

    I've seen three ways to automatically control the pump; pressure sensing like the above system, flow sensing, and timers. Flow sensing uses an impeller wheel such as the transducer in a fuel flow system to monitor the movement of fuel through a line. Good system but fairly expensive. I've also set up timers that run for specific time and then shut off power to the pump. If the operator wants more fuel moved, he actuates the timer and it runs again.

    These are the common choices and you'll have to decide which one is best suited for you. Let me know your thoughts about this.

    Web
    good point about the flow restrictor to build pressure, which also means your pump works a lot longer and harder than it needs to to get the work done.

    best system is still gravity fed, but this doesn't work with belly pods and bladders etc in high wing aircraft...

    I quite like the timer system, but here again you need a robust pump that doesn't mind running the "extra" time your timer is set for after it is emptied.

    flow transducer system sounds too complicated and expensive......

    right now I have the Manual lift system which works as follows, pilot lands and then manually lifts a fuel can onto the wing and refuels, it has its ups and downs....

    my real dream is a belly fuel pod that I can hook on and hook off easily, so fly to camp, unhook fuel pod and leave it as base camp, go explore and play, come back and refuel out of belly pod to get home...... until now I havent figured out a way that I am 100% comfortable with. recently saw a vid on the forum of a cub with a rail underneath that was used to transport a small ATV, this led me to thinking about a cargo net option to sling the fuel cans under the belly..... would be interesting to hear what the speed penalty was for that ATV under the belly.... ok finished rambling now.....

  11. #11
    wireweinie's Avatar
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    Fuel bags with an electric pump? If you have a powered camp, you could use a stand alone battery pack to run the pump, then recharge.

    Or go simple. Fuel bags with clear hose attached to the cap. Put the hose in the aircraft tank and step on the bag.

    Web
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  12. #12
    skywagon8a's Avatar
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    Quote Originally Posted by wireweinie View Post
    I've seen three ways to automatically control the pump; pressure sensing like the above system, flow sensing, and timers. ..
    Web
    Here is a fourth way. Install a sensitive ammeter in the wire to the pump. When the pump runs out of fuel the amperage draw goes down. Then manually shut off the pump. Saw this done on a Widgeon with fuel in the floats.

    Now Web, this would be up your alley. How about an amperage sensing switch? When the amperage drops, the switch opens. Something in the circuit to hold the switch closed while the pump pressure builds.

    This would help the Javelin tank installation by removing the orifice, enabling the fuel to transfer in less time.
    N1PA

  13. #13
    wireweinie's Avatar
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    It's possible. I've made warning light circuits that turned on/off a specific amp level. Might take an little experimenting to get the set point just right. I'd think that a pump that pulled a higher amount of current would be easier to set up with this system.

    Web
    Last edited by wireweinie; 10-23-2020 at 03:00 PM.
    Life's tough . . . wear a cup.

  14. #14
    skywagon8a's Avatar
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    The pumps in the Widgeon were just Facet pulse pumps. Not really high draw pumps. I believe the ammeters measured amps in fractions of an amp. The needle moved over a range of 2 or 3 inches which gave a very visible indications.
    N1PA

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    Just as an update: Took it to a local shop and they were able to identify a grounding problem. Apparently the pump used a case ground on a painted surface, they wired an additional ground to the airframe and the pump works correctly. Only a few hours of labor, not bad.
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  16. #16

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    I have located a Javelin (or O&N) fuel tank that I wish to install in my 180. I was amazed that Cessna offered it as an option in their early production 180 and 185's, so the paperwork is more straightforward, as far as the TCDS goes.
    I need to locate some pictures of the actual installation in an early 180, to determine the mounting of the baggage tank, that is, straps and location of the points for the mounting bolts. I do have the schematics from Cessna, but if anyone if the forum has pictures, I would appreciate your posting them, or sending me a PM.
    I will need to send the tank to Griggs, as it is set up for a 182, so the fuel drain points may be different to a 180. Again, pictures of the drain points in either your 180 or 182 would be of great help.
    Thank you.

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